Tools

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h i

HOW TO MAKE TOOLS

by

PER CHRISTIANSEN

and

BERNARD ZUBROWSKP

This publication was prepared in conjunction with Preserving Food by Drytng, Manual Nl0,and has been designed to assist you in producing tools and equipment that can be used by both yourself and members of your community. Some of the items in this publication were published originally as rfTools for the Class- roomu by Per Christiansen, Bernard Zubrowski and others through the Education Development Center of Newton, Massachusetts under US/AID contract csd-772.

Peace Corps

Information Collection and Exchange d

Reprint R 41

July 1980

September 1981

CONTRIBUTORS

Per Christiansen served as a Peace Corps Volunteer ia the Philippines, 1963-1966 after several years in engineering. Later, he was involved with the science education program for Africa (SEPA) in rural Kenya. He has worked in Peace Corps training programs for countries on every continent. In the U.S., he k . 3 ~ taught science education both in public schools and at the college level.

Bernard Zubrcswski was a Peace Corps Volunteer in Bangladesh, 1962-1964. Later, he worked as a curriculum developer in rural Kenya for SEPA. Since then he has been involved in community and non-formal education in the Boston area.

'--- -I Thanks to Sally Barb Landry, Arnulfo Barayuga and Lance FJellman for photography and art work.

TABLE OF CONTENTS

Section

A . A Temporary Hammer

Paue

1

A C h i s e l

A D r i l l

Saw Made w i t h Two P i e c e s o f Wood

Saw Made w i t h Four S t r a i g h t P i e c e s o f Wood and st ; ; ing

Permanent Hammer w i t h Bamboo Handle

Permaxi.ent Hamtier w i t h Wood Handle

T i n Can D r i l l

Ho ld ing t h e Wood w i t h a Bench Hook

Another Wood Ho lde r

' ~ n i f e f rom Meta l Pack ing M t r i p

Combinat ion Saw and Kni fe

M. A S c r e w d r i v e r

N . Tongs

Tweezers

C u t t i n g T i n Using t h e C h i s e l o r a T in C u t t e r

A H e a t i n g S t a n d Made from a T i n

How t o Make a Round Hole i n a T in

Making an Equa l A r m Balance

D e t e c t i n g Changes i n Tempera tu re Wi thout a Thermometer

Making a S e t o f Weights

V . Conve r s ions Between M e t r i c , B r i t i s h and American Weights and Measures

Section A. A TEMPORARY HAMMER

One tool which you w i l l need i n making almost all the other tools mentioned i n the following pages is a hammer. If you can borrow one o r a sui table subst i tute for a day or so, you can move on to the next sect ion. If not , you can make a temporary hammer quickly.

You w i l l need the f o l l o w i ~ g materials:

One large nut and bo l t t o the dimensions shown

One piece of wood, such as a th ick branch of a tree Length: Not less than 35 crn (cm = centimeter) Circrmference : Between 21 c m and 23 crn

One n a i l , 7% c m long

Three n a i l s , 5 cm long

To measure the circumference of the wood, wrap a piece of string around the wood as shown and mark the s t r i n g . The measure the distance between the mSkXsT- This distance should. be between 21 crn and 23 cm.

With a l a r g e k n i f e , s l ice t h e piece of wood down t h e middle to a d i s t a n c e of 16 cen t imeters . Force t h e b o l t i n t o t h e s l i t and down f o u r

cen t imeters from t h e top. P lace t h e n u t on t h e b o l t .

To keep t h e b o l t i n p l a c e and t h e wood from s p l i t t i n g further, you w i l l need to hammer a f e w n a i l s as shown i n the diagram. A heavy s t o n e can be used t o drive i n t h e n a i l s .

Sect ion B. A CHZSEL

s YOU w i l l o f ten need t o cut off small pieces of wood from I a l a r g e piece, o r cut a t i n . The chisel will heip you do

, t h e s e th ings , as we l l as w n y other kinds of cutting work,

- To make a c h i s e l you w i l l need:

One n a i l , 15 crn long *

Hammer

You w i l l a l s o need a very hard surface t o work on. You could use a piece of i ron from an old automobile, or any other kind of sc rap i ron . Sometimes a heavy piece of inetal i s around t h e school compound, such as metal t h a t i s banged t o make a sound c a l l i n g the pup i l s together for assembly.

put the n a i l on &e piece of iron, arid, with t h e hammer, hit t h e pointed end o f the n a i l until it is flattened. The following t h r e e diagrams show (A) a 15 c m n a i l before hammering, (B) t h e hamered n a i l f r o m a top view and (C) t h e hammered n a i l from a side view, showing how it has been f l a t t e n e d .

Diagram C

The n a i l is then c u t with a hacksaw blads t o g e t a f l a t edge. The fol lowing diagrams show t h e angle of c u t t o be made. ,--'I .

-.-' I

A f t e r c u t t i n g , t h e edge needs t o be sharpened by r u b b i ~ g it a g a i n s t a ha rd rock. I f a hard rock canrlot be found, you can buy a small f i l e . After sharpening t h e edge should look l i k e t h e one i n t h e following diagram.

Remember t h a t f i l e s a r e made of metal which w i l l rust e a s i l y . Rust destroys t h e sharp edges an t h e t e e t h of t h e f i l e . A small amount of cooking o i l o r . f a t can be put on t h e f i l e after it is used each t i m e and t h i s w i l l prevent r u s t .

Mosc n a i l s you buy w i l l probably be made of s o f t metal. When you use t h e c h i s e l it w i l l become damaged o r blunted quickly. You can harden t h e t i p by t h e following procedure. Make a (fire and p lace t h e end of She n a i l i n t h e f i r e , keeping it t h e r e u n t i l it is glowing red. Then drop it quickly i n t o a t i n of cold w a t e r . Repeat t h i s procedure s e v e r a l t i m e s .

U s i n g the C h i s e l

The c h i s e l is very useful i n shaping wood o r c u t t i n g holes i n wood. When pup i l s make holes i n wood, they usual ly t r y t o c h i p out b ig p ieces of wood. It w i l l be easier i f they cu t only small p ieces a t a t i m e . This p r a c t i c e w i l l a l s o preserve t h e c h i s e l . There w i l l be occasions when you o r your pup i l s w i l l want to c h i p away p a r t of a p iece of wood t o g e t a cer- t a i n width. Again, chip o f f small s l i c e s a t a time u n t i l t h e d e s i r e d th ickness i s reached.

I

Ancther use f o r t h e c h i s e l i s the cutting of t i n s . --

Cut t ing on a hard surface w i l l d a ~ a g e t h e point 02 t h e c h i s e l . Be su re t o place the tiL G ; ~ a wooden sarface such as a th ick tree branch. When you cu t through the t i n , the point w i l l go i n t o the wood and t h e c h i s e l w i l l need to be pu l l ed o u t before making t h e next c u t .

R e m e m b e r t h a t the c h i s e l cu t s best when it is sharp. Keep a hard s tone o r file around t h e classroom and encourage t h e pup i l s t o use these sharpening t o o l s of ten .

Sect ion C. A DRILL

Sometimes you may need t o make a s m a l l hole through a p iece of wood. The following t o o l w i l l help you do th i s .

You w i l l need t h e s e materials t o make t h e d r i l l :

One n a i l , 8 cm long

One piece of wood such as a branch of a t r e e k ! The wood should be very hard

~ e n g t h : about 1 2 c m Thickness: between 10 and 1 2 cm (See page 1 f o r i n s t r u c t i o n s on measuring t h e thickness . )

Hammer

%'he first step i s t o f l a t t e n t h e po in t of t h e n a i l as you did when making t h e c h i s e l . Hammer t h e p o i n t u n t i l flattened as shown i n t h e diagram. _ __ --- - -- -

The f l a t t e n e d p o i n t is then hammered i n t o t h e cen te r of t h e end of t h e p iece of wood as shown i n t h e following diagram. Cut t h e head off t h e n a i l w i t h a hacksaw blade. T h i s exposed end of t h e n a i l is hammered u n t i l it is f l a t t ened .

N a i l with head o f f before being f l a t t e n e d :

N a i l after being hammered:

F ina l ly , sharpen t h e end us ing a hard s tone , o r by rubbing it on a hard cement f l o o r until t7 - ?o in t looks l i k e this:

The same procedure can be used t o make drills of various s i z e s , using d i f f e r e n t s i zed nails. When using large n a i l s , make su re t h e wood f o r the handle i s t h i c k enough i n diameter s o t h a t it w i l l not crack or split when t h e d r i l l is being used.

TO use t h e d r i l l , grasp t h e butt OF t h e handle w i t h t h e palm of t h e hand as shown i n the diagram. Press down as you twist t h e n a i l back and forth through t h e wood.

The d r i l l a l s o can be used t o prepare a piece of wood f o r a n a i l . I f a hole is made i n a piece of woed before a n a i l i s pounded i n t o it, t h e wood wzll be l e s s l i k e l y t o s p l i t . Choose a d r i l l which w i l l make a hole t h a t is s l i g h t l y smaller i n diameter than t h e n a i l that you want t o use. D r i l l t h e hole no t q u i t e through t h e o t h e r end. When jo in ing two pieces of wood, do t h i s f o r both pieces . Then bang t h e n a i l through t h e holes i n t h e two pieces.

Sect ion D. SAW &ADE WITH TWO P I E C E S OF WOOD

You w i l l need t h e fol lowing mate r i a l s :

.one hacksaw blade which can be of e i t h e r of t h e two types shown i n the diagram. The length can be 25 o r 30 cm.

One small tree branch A branch which divides i n t o two branches of about equal th icknesses s h l d be found. The blade can be used to c u t it from t h e t r e e .

The t h i n n e s t part of t h i s p iece of wood should be measured t o make s u r e it is t h i c k enough. It should be a t least 8 c m around. The wood must be s t r o n g enough s o t h a t t h e hacksaw blade remains tight. If t h e wood is t o o thin, it w i l l bend when t h e s a w is being used, and t h e blade w i l l a l s o bend. The blade w i l l las t longer t h e less it bends.

YOU w i l l a l s o need:

One s t r a i g h t - p l % c e x w x - a b o u t 18 cm long

Four N a i l s For most p ieces of wood, it i s b e s t t o use t h r e e n a i l s t h a t have a length of 4 c m and one n a i l t h a t has a length of 2 t o 3 cm. For p ieces of wood t h a t are much t h i c k e r than t h e measurements shown above, n a i l s t h a t have a length of 5 c m are needed.

Hammer

D r i l l

Making t h e Saw

~f necessary, cu t off t h e t w o bottom ends of t h e piece of wood so that the distance between the two ends i s the same as t h e length of t h e hacksaw blade.

1 The hacksaw blade is used to make a cut i n each end of t h e piece of wood. These c u t s should be a l igned with each o the r

t so t h a t t h e blade can be placed i n t o t h e c u t s without be- coming bent . The c u t s should be about as deep as the width of the blade.

Before p u t t i n g t h e blade i n t o the cuts, use t h e d r i l l to make a hole at each end where t h e n a i l s w i l l be placed. Now the blade can be put i n t o each slot and a 4 cm n a i l put through each hole i n t h e wood and each hole i n the blade. The n a i l s are then bent over with a hammer. Tine s t r a i g h t p iece of wood should now be cut so t h a t it f i t s i n t o t h e saw as shown i n the diagram.

d i s t a n c e be 10-12

ent n a i l s

Next, hammer a 4 c m n a i l through one s ide of t he piece of wood and i n t o t he end of the s t r a i g h t piece of wood as shown i n the diagram a t A. Pu l l the shor t piece of wood upwards t o tighten t he blade and hammer the smaller n a i l (2 or" 3 cm) j u s t below the end of t h e sho r t piece as shown i n the diagram a t B.

The s a w is now ready t o use. Caution. the pupi ls not t o bend the blade while sawing f o r i f it i s bent a t t o o much of an angle, it may break.

You should check the t ightness of t h e blade i n t h i s kind of s a w every few weeks. If you f ind a saw with a loose blade, ask t h e pup i l who owns t h e s a w t o p u r l - t5e movable -end of - the s h o r t piece upwards and hammer the shor t n a i l i n a new place. By reposi t ioning the brace i n t h i s way, the blade w i l l be tightened. Have the pupil ask a f r i end t o help since one person must usually hold the shor t piece while another hammrs.

i . - - o l e ~ w i t h

&e 1 0 - 1 2 cm e n t n a i l s

Section E. SAW NAEE WrTB F O U R STRAIGHT PIECES OF WOOD AND STRING

The materials you w i l l need are :

One hacksaw blade which can be e i t h e r of t h e two types shown i n Section D The length can be 25 o r 30 cm.

Four s t r a i g h t pieces of wood from tree branches. Length: larger than 36 c m but less than 38 cm Circumference: between 8 and 10 c m One of these pieces i s s p l i t along i ts length i n t o two equal pieces.

One piece of s t r i n g which measures more than 200 cm but less than 250 c m

Two n a i l s , 4 cm long '

Two n a i l s , - 6 % c m long

Hammer

D r i l l

Chisel

heavy knife can g l so be used. (Sometimes c a l l e d a machete, panga, bolo i n various countr ies .)

~ a k i n q the Saw

F i r s t , a hole i s made nea r each end of t h e two s p l i t p ieces of wood using t h e d r i l l . D r i l l t he ho les wide enough f o r a 6% cm n a i l t o be hammered through without s p l i t t i n g t h e wood. The holes should be 3 t o 5 cm from t h e ends of t h e s t i c k s . his procedure is shown i n Diagram A. Next, drill one hole i n each of two of t h e o t h e r p ieces of wood. Each hole i s 1 2 t o 15 cm from one end 0'5 t h e wood. This procedure i s shown i n Diagram B.

*% (. Diagram A . Diagram B

The four pieces of wood are then joined together us ing 6% c m n a i l s as shown i n D i a g r a m C. The ends of t h e r a i l s a r e bent us ing a hammer. D o t h i s c a r e f u l l y s o t h a t t h e p ieces of wood do no t s p l i t .

Diagram C . . ,

A c u t is now xade i n t h e ends of t h e two p ieces of wood where t h e blade i s t o be a t tached. The blade should be a b l e t o f i t i n t o t h e two c u t s without it becoring bent.

A hole is now made near each end of t h e p ieces of wood t where t h e c u t s have j u s t been made. Each hole i s placed so

t h a t t h e n a i l w i l l go through both t h e hole i n t h e wood and t h e hole i n t h e end of the b l a d e , Use a hammer t o bend t h e n a i l s which hold t h e blade. D o t h i s carefully t o avoid damaging t h e wood o r t h e blade.

a A here

Cpptf are 'b . . . I . , . . , '. .. . ~ ma&e

here

Notches are then made between 3 and 5 cm from t h e ends of t he p ieces of wood where t h e s t r i n g i s t o be a t tached.

Attach t h e s t r i n g by wrapping it around t h e two p ieces of wood a t t h e notches. The s t r i n g should be wrapped 2 o r 3 times and then t i e d together . Put t h e l a s t piece of ~ o o d through t h e s t r i n g and t u r n u n t i l t h e s t r i n g t w i s t s enough t o t i g h t e n t h e blade.

The s a w i s now ready to use.

YOU can check the t i g h t n e s s of t h e blade i n t h i s kind of s a w by t h e t i g h t n e s s o r looseness of t h e s t r i n g s . If a pup i l has t i gh tened h i s o r h e r saw too much and t h e s t r i n g has broken so t h a t most of it i s l o s t , it may no longer be poss ib le t o t i g h t e n t h e blade properly. Sometimes p u p i l s w i l l a t tempt t o use t h e i r s a w s with no s t r i n g , or with a broken p iece of wood. If you find a saw t h a t needs a p a r t replaced, ask t h e pupil who owns the saw t o replace t h e broken s t r i n g or p iece of wood before using t h e s a w again. Remind t h e pup i l s t h a t i f they do no t do t h i s , t h e i r blade w i l l soon become broken and it is expensive t o replace a blade.

Sect ion F. PERMANENT HAMMER W I T H BAMBOO HANDLE -

Bamboo can be used to make a handle for a permanent hammer. It is a good material f o r making the handle i f a s t rong type is ava i l ab le . It is a l s o very easy t o make a handle using t h i s ma te r i a l .

You w i l l need the following mater ia ls :

One p iece of bamboo which i s between 30 and 40 crn long and with a circumference between 1 2 and 16 cm,

One large nut and b o l t (see Temporary Hammer for dimensions)

Saw

Temporary Hammer

Chisel

Making t h e H a m m e r

Saw t h e bamboo as shown i n Diagram A. Make two small cu t s i n the bamboo 2 c m a p a r t as shown on diagram. These two cuts should be near t h e end which includes the j o i n t [where t h e branches once grew) . U s e t h e chisel, and h a m m e r . t o remove t h e piece of bamboo s o t h a t t h e r e i s a h ~ l e . Now do t h e s a m e t h i n g on t h e o t h e r s i d e of t h e bamboo s o t h a t t h e b o l t can be put through t h e opening and t h e nu t t ightened.

ch i se l o u t t h i s a r e a

Diagram A

, I

After t h e bolt has been put through t h e bamboo handle, and the n u t screwed on unt i l , t b e b o l t is no t l oose , t h e hammer i s ready f o r use.

M z k i n g t h e H a m m e r into a Nail Remover - Sometimes when hammering n a i l s i n t o wood, it is necessary t o s t o p and remove t h e n a i l because it is ben t o r w i l l n o t go

' i n t o t h a t p a r t i c u l a r spot. You can cu t a s l o t i n your b o l t ', ,! . ..

. , ; I - , . which w i l l enab le you t o use it as a n a i l remover. You can e . only .make the n a i l remover i f the b o l t i s s t i c k i n g ou t about

. 1 cm or more from t h e nu t .

I n c u t t i n g t h e b o l t w i t h t h e hacksaw, first make a v e r t i c a l c u t about 1 c m deep. Then c u t between 2 and 3 ~XIJ away from the first c u t . (mrn = m i l l i m e t e r ; a millimeter is one t e n t h of a cen t imeter . This second c u t s l ~ o u l d be a d iagona l one. It is important t h a t t h e cut be made no l a r g e r than 3 mrn. If t h e c u t i s w i d e r , it w i l l be d i f f e c u l t to remove any n a i l s .

The s l o t shou ld be w i d e enough s o t h a t a 6% c m n a i l can f i t i n t o it, b u t n o t w i d e enough f o r a 7% c m n a i l t o f i t . If t h e s l o t i s w i d e r t han t h i s , t h e heads of smaller n a i l s w i l l n o t be caught by t h e s lo t . Since t h e p u p i l s work mostly wi th 4 and 5 c m n a i l s , t h i s i s very important .

I f t h e p i ece o f metal does not come ou t after you have made t h e c u t s , move it back and f o r t h u n t i l you can force it o u t w i t h a n a i l or o t h e r s m a l l po in t ed o b j e c t .

make 1 vertical cut I

1 cm deep !

--.

I cut :, I

daqonal~y; h: !

Sect ion G. PERMANENT HAMMER WITH WOOD HANDLE

If bamboo i s no t a v a i l a b l e i n your a rea , you can make a permanent hammer using a t h i c k branch from a tree.

You w i l l need t h e fol lowing mater ia ls : 1

One p iece of wood, 30 cm long and 1 2 t o 16 c m around I ,

One l a r g e rut and b o l t

Chisel

Temporary hammer

Heavy k n i f e

Making the Hammer

with a heavy kn i fe , such as a panga o r machete, shape t h e lower part of t h e branch s o t h a t it has t h e form shown i n t h e fol lowing diagram.

pencil mark - _ -.--

ham handis so it is csmfot?ab!e Chisel out to hold. this area.

Mark of f t h e area a t t h e t h i c k end of t h e handle where t h e b o l t w i l l go. With a c h i s e l and a hammer, c u t through t h e wood i n s i d e t h e penc i l mark u n t i l you have made a hole com- p l e t e l y through t h e th ickness of the wood. Remember t o c u t away s m a l l p i e c e s a t a t i m e . When you t h i n k t h e hole looks b i g enough, t ry fo rc ing t h e bolt through. If it does not f i t , keep c u t t i n g with t h e c h i s e l u n t i l it does. Try t o cut the hole s o t h a t t h e b o l t w i l l f i t t i g h t l y . F ina l ly , push the b o l t through, and p lace t h e nut t i g h t l y on the end of t h e b o l t . A n a i l remover can alsc. be added t o t h i s type of hammer (See Section F>.

Sect ion H. TIN .CAN D R I L L

The t i n can d r i l l i s a t o o l which i s r e l a t i v e l y easy t o make D r i l l i n g holes with t h i s tool i s quicker and takes l e s s e f f o than d r i l l i n g ho les with the manual d r i l l descr ibed earlier.

n a i 1

DIAGRAM A

You w i l l need t h e fol lowing mater ia ls :

~ n e ' l a r g e coffee t i n with f i t t i n g l i d

Pcle (dowel or p iece of branch) 1 m e t e r long, 6-8 cm around

Two blocks of wood 3 cm wide, 10 c m long and about as th ick as t h e rod

Leather s t t a p o r s t r o n g twine which i s approximately 7 decimeters long

One piece of wire approximately the same thickness a s a coathanger, a l i t t l e b i t longer than t h e diameter

E igh t n a i l s , 4 cm long

Nine n a i l s , 2% cm long

One nail,, 5 c m long / i

s a w

D r i l l

Method for Making the D r i l l

C u t a rod which i s approximately 1 meter long and 6-8 c m around. Cut t h i s r a d i n h a l f t o form two pieces which are 5 decimeters each. One of t h e s e forms t h e cen te r pole (A) and the o the r p iece needs t o be cut i n half again t o form pieces B and C.

Diagram B

Now cut two blocks of wood (D and E) which a r e approximately 10 c m long, 3 c m wlde, and about as t h i c k as t h e rod. These blocks w i l l secure B and C i n p lace t o form t h e handle. B and C should be j u s t f a r enough a p a r t t o allow t h e c e n t e r pole (A) t o s l i d e e a s i l y through a s shown i n Diagram C.

Diagram C

c u t holes i n t h e t o p and bottom of* t h e 1 kilogram coffee can which are j u s t b i g enough f o r the pole (A) t o f i t snugly through. These holes need t o be i n t h e very c e n t e r of each end.

The next s t e p is t o w i r e t he rod t o t h e can near t h e t o p of t h e can. Punch two holes i n oppos i te s ides of t h e can near t h e t o p using a n a i l . Now d r i l l a hole through t h e pole . To determine where you want t h e hole, hold t h e pole next t o t h e can w i t h t h e bottom end sf t h e pole extending approximately 3 cm below t h e bottuir: edge of the can. Mark t h e p o i n t on t h e rod which is between t h e two ssna19 holes i n t h e can. A t t h i s p o i n t d r i l l your hole . Now pass a w i r e through t h e hole i n t h e pole and bath holes i n the t i n . Bend each end of t h e wire where it comes out of t h e can. The c e n t e r of t h e w i r e passes through t h e hole i n t h e pole.

Nail t h e middle of t h e l e a t h e r s t r a p t o t h e top of pole A. N a i l t h e ends of t h e s t r a p ( o r twine) t o t h e ends of blocks D and E as shown i n Diagram A. The s t r a p (twine) should be j u s t long enough t o hana t h e handle approximately 3 cm - from t h e t o p of t h e can a t i ts lowest poin t . Secure t h e s t r a p , by lash ing , t ap ing o r t ack l ing , t o t h e t o p of t h e pole.

The next s t e p is t o a t t a c h t h e po in t of t h e d r i l l . F l a t t e n t h e end of a 5 cm n a i l . Pound t h e 5 c m n a i l i n t o the bottom of pole A. A t l e a s t 3 cm of t h e n a i l should be showing. Cut of f t h e head of t h e n a i l (as descr ibed i n s e c t i o n C). F i l e t h e end of t h e n a i l t o a po in t . The n a i l w i l l t need t o be resharpened from t i m e t o t i m e . The s i z e of t h e n a i l .

w i l l determine t h e s i z e of t h e hole t h a t can be d r i l l e d . You may want t o make d i f f e r e n t d r i l l s with d i f f e r e n t s i zed po in t s . F i l l t h e can with rocks, sand, o r some o t h e r heavy material. Your d r i l l i s now ready t o use.

To use t h e d r i l l , f i r s t t w i s t t h e handle s o t h a t t h e s t r a p is would up a l l t h e way, then pump t h e handle up and down giving t h e can a back and f o r t h r o t a r y motion.

'P

I. H o l d i n q t h e Wood w i t h a Bench Hook

When sawing or d r i l l i n g wood it i s often a problem t o hold the p iece o f wood s o that it does not move. This i s e s p e c i a l l y true when a person i s working without another person t o he lp . A simple piece of equipment to hold a branch i s shown i n the diagram above. The folloxiing diagram shows t h i s support being used. This i s c a l l e d a bench hook.

you w i l l need t h e followlnf GteFXalg:

Three p ieces of wood more than 30 c m bu t less than 36 c m long and between 6 and 8 an around

TWO p ieces of wood which are between 113 and 13 cm long and are between 6 and 8 un around

Six n a i l s , 5 cm long

Saw

Hammer

D r i l l

Chisel

The t h r e e longer pieces of wood a r e used as they are. The two smaller pieces of wood are ch i se led so t h a t they have t h e shape shown i n t h e diagram below.

_ --.- _2__

. . D r i l l t h r e e holes i n each ~f t h e t w o smaller pieces of wood, i n t h e p laces shown i n t h e diagrsm below.

Attach one s-mll piece of wood t o t h e t o p of one end of t h e three longer pieces, and t h e semmJ small piece under- nea th t h e o t h e r end of t h e t h r e e longer p ieces . This can be done by p u t t i n g a n a i l i n t o each hole i n t h e s h o r t p ieces and hammering each n a i l through and i n t o a long piece. To secure, h-r t h e p o i n t s of tZle n a i l s s o they are bent back. The bench hook is then ready f o r use; it looks l i k e t h e one shown i n the diagram at t h e beginning of t h i s sec t ion .

Section J. ANOTHER WOOD HOLDER

Four wood holders a r e usually needed t o hold a piece of wood v e r t i c a l l y f o r sawing. See Diagram B on .page 25.

To make the wood holders you w i l l need the following materials:

Four pieces of wood Length: more than 8 cm but less than 10 cm Circumference: If a s t r i n g is pu t around t h e wood and marked, the marks on the s t r i n g should be between 6 and 8 cm apa r t

1

Four n a i l s , 5 cm long

Hammer

Saw

D r i l l

Bench Hook

Making a Wood H o l d e r

U s e a drill t o make a hole i n the center of a piece of wood. Choose a d r i l l which w i l l make a hole t h a t i s s l i g h t l y smaller than the n a i l t h a t wi l l f i t i n t o it. D r i l l t he hole almost through the o ther s ide of the wood. Diagram A shows the wood supported by a bench hook while being d r i l l e d . Then h w r t h e n a i l through the hole u n t i l the head of the n a i l reaches the wood. The bes t place t o do t h i s is on s o f t ground from which the n a i l , attached now t o the wood, can e a s i l y be removed.

..,. - - - - .

DIAGRAM A

Four of these wood holders can be used to hold what you are sawing securely against a Tog o r large piece o f wood as shown

. . DIAGRAM B -.

Section K. K N I F E FROM .METAL P A C K I N G S T R I P

Materials f o r t h e kn i fe :

One piece of metal s t r app ing Erom an o l d packing c r a t e . me m e t a l s t r i p should be of a kind t h a t i s thick and does n o t bend e a s i l y .

Length: about 10 c m Width: about 2 cm

Two n a i l s , 4 an long

One n a i l , 15 c m long

One piece of wood 1 2 cm long and 10 cm around

Saw

Making the K n i f e

Put ho les i n one end of t h e m e t a l s t r i p . U s e the 15 c m n a i l to make the holes. The holes should be placed i n t h e m e t a l strip as shown i n t h e diagram.

~ n o t a l strip

~f the pkece of wood is a branch of a tree, cut o u t one part as shown i n t h e diagram.

Hammer the two n a i l s through t h e holes i n the metal and through the wood. Use a s a w to c u t ~ f f the ends of t h e n a i l s . Sharpen one edge of the metal on a hard stone or with a file. The kni fe i s now ready t o use.

Caution your pupils about using these knives. Some child- ren w i l l use t h e kn i fe s o that the sharp edge is coming towards them. T h i ~ is dangerous. Tell them t o carve away froa themselves. They can a l s o carve an a table.

Sect ion L. COMBINATION SAW dld K N I F E

Materials you w i l l need t o make t he combination s a w and k n i f e are:

One broken hacksaw blade betwszc 12 and 1 4 c m long

One piece sf wood Length: b e t w e n 10 and 1 2 an Circumference; between 9 and 10 c m (as measured by s t r i n g )

One nai l , 5 cm long

Saw

D r i l l

Making the C o m b i n a t i o n Saw and Knife

The p iece of wood i s c u t along t h e length of t h e s t i c k as shown i n t h e fol lowing diagram. The depth of t h e c u t should be equal t o t h e width of t h e blade.

- -- _ _-CC_ - hole drilled throuqh--

D r i l l a hole with a small diameter i n t h e middle of t h e stick as shown. The broken hacksaw blade i s i n s e r t e d i n t o t h e s l o t u n t i l the hole i n t h e blade is l i n e d up with t h e hole i n t h e woc;P. The n a i l is then i n se r t ed . Bend over t h e nail. which s t icl~s out of t h e o the r side.

The edge of t h e blade_ t h a t does no t have t e e t h should be sharp- e n e d o n - a hard s tone o r with a f i le . You now have a t o o l which can be used as a k n i f e o r a s a small saw.

Sect ion M. A SCREWDRIVER

I n c e r t a i n schools, ch i ldren may be a b l e t o use screws, i n s t e a d of n a i l s , f o r jo in ing p ieces of wood. If screws are a v a i l a b l e i n your school, your pup i l s w i l l f i n d t h i s screwdriver usefu l .

YOU w i l l need t h e fol lowing mater ia ls :

me p iece of wood Length: more than 9 cm but less than 1 4 c m Circumference: If a s t r i n g i s put around t h e wood and marked t h e marks should be more than 1 2 c m but less than 15 cm


Saw

Hammer

Chisel

Bench Hook

D r i l l

Making t h e S c r e w d r i v e r

U s e t h e bench hook as a support . Then, with a c h i s e l and hammer o r a heavy kn i fe , shape t h e p iece of wood s o t h a t it looks l i k e t h e handle shown i n t h e diagram.

U s e a d r i l l t h a t w i l l make a hole a l i t t l e smaller than t h e n a i l . Make a hole i n t h e end o f t h e handle as deep as it i s poss ib le t o make with t h e d r i l l . U s e t h e s a w t o c u t t h e n a i l near t h e head of t h e n a i l , a s shown i n t h e diagram.

-------- cut off head b. ------.

F l a t t e n t h e part of t h e n a i l where you have cu-c it u n t i l it looks l i k e t h i s :

I End A End 6 . - .

This end w i l l be t h e one which is banged into t h e wooden handle. F l a t t e n t h e o t h e r end of t h e n a i l (End B) u n t i l it looks l i k e this:

Decide how t h i c k t h e poin t of t h e screwdriver w i l l be. This c o n t r o l s where you w i l l cu t o f f t h e f l a t t e n e d p a r t of t h e n a i l . Use a saw t o cut off t h e end of t h e . n a i l .

-__ - -- - -- -- . cut - -

D A l i t t l e rubbing on a piece of s tone , or some f i3 ing , may be needed'to remove sha rp p ieces of metal. -

- - -- before rubbina

. . - - . - - - - - --- -

When t h e p o i n t of t h e screwdriver i s complete, it should look l i k e t h i s :

Too much rubbing-on a s tone can destroy t h e usefulness as a screwdriver; i f t h e po in t looks l i k e t h i s , it is n o t good.

~ o s t n a i l s t h a t you w i l l buy are probably of a s o f t metal . When you use t h e screwdriver, t h e p o i n t of it w i l l become damaged o r twis t ed quickly. You can harden t h e po in t by using t h e method which is descr ibed in making t h e c h i s e l p o i n t hard ( Section B ) .

~t i s only necessary t o harden t h e end of t h e n a i l which w i l l be t h e blade of the screwdriver. The o t h e r end, which has been roughly f l a t t e n e d , does n o t need hardening.

NOW put t h e blade of t h e screwdriver on a l a rge p iece of s o f t wood and hold t h e handle s o t h a t t h e f l a t t e n e d part of t h e n a i l ( ~ n d A) is i n t h e hole i n t h e handle. TJse a hammer t o h i t t h e o t h e r end of t h e handle s o t h a t t h e f l a t t e n e d end of t h e n a i l goes i n t o t h e hole i n t h e handle. When the

- - A - - -- - n a i l seems f i rmly-a t t ach=d i n t h e handle, s t o p hammering. T w i s t t h e screwdriver gen t ly t o remove t h e blade from t h e l a r g e p iece of s o f t wood. ~ h e - s c r e w d r i v e r is now ready t o use.

Sect ion N. TONGS

There may be occasions when you need t o remove h o t o b j e c t s from a fire such as a h o t n a i l o r pot . A use fu l t o o l f o r t h i s purpose is a p a i r o f tongs. These can be made e a s i l y f r o m a tree branch.

Y o u w i l l need t h e fol lowing materials:

One s t r a i g h t branch Length: Not less than 17 c m Circumference: Between 8 and 9 c m


Saw

Hammer

Chisel

Four wood holders

Bench Hook

Making the T o n g s

Secure t h e branch t o a tree o r log with wood holders . Make a cut 13 c m i n length i n t h e branch, as shown.

1, Now remove t h e branch from t h e wood holders . Cut off t h e e x t r a wood a t t h e o t h e r end, s o your p iece i s 1 7 c m long. Again, hold ghe branch with wood holders t h i s time with t h e end with the 13 c m c u t down. The end t h a t is up should now be cut t o a depth of 4 m a t r i g h t a n g l e s t o t h e 13 c m c u t . Thediagrams i l l u s t r a t e t h e s e c u t s .

Actmi Size .-. . _ _ -_ - - --- -- ._ .- ___ _ _ . . . _ _ _ .

Use your chisel and hammer t o chip away a t point "A" as shown i n t h e diagram. Chisel a l i t t l e away at G time. D o this u n t i l the cuts are connected. Turn the branch over and do the same thing to connect t h e two cuts on the other side.

At this po in t you should be able t o pul l the branch apart i n t o two p i e c e s a s shown i n the diagram.

h o l e \

hole \

With a d r i l l , make a hole t h r o u ~ h both pieces. Put a n a i l through these t w o ho les . Bend the pointed end of the n a i l . Your tongs are now completed.

Sect ion 0. TWEEZERS

There w i l l be some occasions when you w i l l be working with small ob jec t s . It may be d i f f i c u l e t o handle these ob jec t s . There may a l s o be t i m e s when you want t o pull out some s m a l l ob jec t which i s i n s i d e a c e r t a i n device, and you cannot get a t . i t with your f inge r s . In these s i t u a t i o n s you can use tweezers.

Tweezers from a Branch

Find a s m a l l branch af a tree which i s "Y" shaped. Cut off t h e bigger branch so that it i s of a s i z e which, w i l l f i t n i ce ly i n t h e palm of your hand. Make s u r e it is f l e x i b l e . That is , squeeze t h e two arms u n t i l they touch each otner . When you l e t go, t hey will spr ing back t o t h e i r o r i g i n a l pos i t ion .

With a sharp knife, tapered. Any small picked up.

cu t t h e ends so that they are th in and o b j e c t , such as a nail o r p in , can be

Metal Strapping Tweezers

Use a piece of metal s t rapping from an o l d packing c r a t e t o make t h e s e tweezers. Try t o ge t a s t r i p t h i c k enough t o be a bit rigid but s t i l l somewhat f l e x i b l e . Its length can be between 20 and 24 an. ~ o u n d o f f t h e two ends by rubbing t h e metal on a hard s tone. Bend t h i s piece i n h a l f .

The two a r m s should spr ing back t o t h e i r o r i g i n a l p o s i t i o n when your f i n g e r s are n o t pushing them together .

Bamboo S t r i p Tweezers

Find a piece of bamboo t h a t i s about 28 t o 30 crn i n length . With a heavy kni fe , cu t a 1 c m wide p iece from t h e l a r g e bamboo. If t h e s t r i p is very t h i c k , cut some of t h e i n s i d e away with a k n i f e u n t i l it i s about % c m i n thickness . With t h e shiny s i d e down, make two s m a l l cuts on t h e rough side.

-_ ----c cuts

Careful ly bend the- s t r i p a t t h e two c u t s s o t h a t t h e shiny s i d e i s i n s i d e . With a knife ,shave t h e two ends so t h a t they are t h i n and come t o a point.

Sect ion P. TIN CUTTING U S I N G THE C H I S E L OR A T I N CUTTER

A convenient way t o c u t t i n s i s t o na lJ -a-pole i n t o t h e t o p of a work table. The board shown i n Diagram A has been rounded n e a r i t s end and has been n a i l e d i n t o t h e table. bout 15 cm of the-i50aTaa-are beyond .tl%e-edge of t h e table. A t i n can be pu t on this p a r t of t h e pole , and then c u t w i t h . a c h i s e l and a hammer as shown i?, Diagram B. I n t h i s way, a u s e f u l square o r rec tangu la r p iece of metal can be cut out of each t i n . The remaining t i n i s a l s o use fu l as a s t a n d for hea t ing th ings .

DIAGRAM A- .. .

~t is a l s o poss ib le t o cu t a piece of metal from a t i n without n a i l i n g a pole onto a t a b l e . This method, shown below, is much more &iff i c u l t .

A special t o o l f o r c u t t i n g t h e top out o f a t i n can be made w i t h a 15 cm n a i l . Rub t h e head of t h e n a i l on a rough s tone o r rough cement f l o o r u n t i l it has t h e s h w e shown i n Diagram ,l

Wan nail OTtcrmbbii u- /

- . DIAGRAM C

The sharpened edge of t h e n a i l i s now placed a t t h e edge of t h e t i n , and t h e o t h e r p a r t of t h e head i s h i t with a hammer as shown i n Diagram D.

. .., - - . - -. -- DIAGRAM D

Each t i m e t h e hammer h i t s t h e n a i l , a small p a r t of t h e t i n is c u t . Move t h e n a i l and h i t it again. DQ this unfiil t h e t o p of t h e t i n i s lemoved.

section Q. A H E A T I N G STAND MADE FROM A T I N

using one of the inethods of cu t t ing a t i n shown previously, you can make heating stands: while you obtair. rectangular p ieces of metal t o use for other purposes.

The stand is used l i k e t h i s :

It has the advantages that 1 . a breeze w i l l not disturb

the flame, and 2 . heat can be prevented

from r i s i n g a l l around what i s being heated, which might contain something that could

/ burn or melt.

40

sec t ion R. H O P TO MAKE A ROUND HOLE I N A TIN --

I n cases where one wants t o i n s e r t a tube i n t o a t i n t i g h t l y s o t h a t there i s no leakage between t h e tube and t h e hole it f i t s i n t o , i t is necessary t o make a round hole i n t h e t i n . If t h e h o l e i s l a r g e enough t o be a b l e t o f i t t h e case of a Bic pen i n t o (or a very small hollow bamboo branch) use t h e following method. F i r s t , make a t i n y hole with a n a i l having a l eng th of 5 centimeters. Then en la rge t h e hole with a 6% c m n a i l , followed by a 10 cm n a i l , and l a s t l y by a 15 cm n a i l . rt 1s important t h a t t h e s e four n a i l s be used i n t h i s way. If only t h e largest n a i l i s used, it w i l l make a square hole because t h e po in t of t h e n a i l has four s ides .

Section S. MAKING AN E Q U A L ARM BALANCE

Many sc ience l e s sons can be improved by having weighing equipment a v a i l a b l e f o r t h e s t u d e n t s t o use. @ t e n t h e r e is only one tr iple arm balance o r weighing s c a l e i n t h e sc ience room, and the t eacher i s apprehensive t h a t it may become broken i f s tudents are allowed t o use it.

Simple des igns f o r equa l arm balances t h a t can be made from e a s i l y a v a i l a b l j m a t e r i a l s are shown he re .

Several d e t a i l s of design affect how s e n s i t i v e a balance is:

1. F r i c t i o n a t t h e c e n t e r p o i n t . 2. Whether t h e c e n t e r ho le i s p laced above o r below t h e

end holes . 3. The weight of t h e beam and where t h e c e n t e r of g r a v i t y

o f t h e beam is l o c a t e d compared t o t h e c e n t e r hole .

Friction a t t h e c e n t e r p o i n t can be k e p t very low as long as t h e p ivo t u s e s r o l l i n g i n s t q a d of s l i d i n g f r i c t i o n . Using a n a i l t h a t rolls on t h e edcjes of t i n s i s one e f f e c t i v e way t o keep f r i c t i o n a t t h e p i v o t from being a problem, and is t h e method used i n . t h e . diagrams t h a t follow.

To investigate the effect of having the end holes a . below the center hale , and b. in line with the center hole,

make the holes shown i n the follcwing diagram in a wooden ruler.

- - .

put a n a i l i n t h e c e n t e r ho le , which is approximately a t t h e c e n t e r of g r a v i t y of t h e r u l e r . Then hang a hook o r l ight-weight con ta ine r f r o m t h e lower h o l e s a t each end of t h e r u l e r . G e t many small o b j e c t s t h a t a l l have t h e same weight. These could be Common pins , Paper c l i p s o r s t a p l e s . me of t h e s e objects should be enough t o unbalance t h e r u l e r . ( ~ f t h e r u l e r does n o t hang l e v e l a t first, . p u t an e l a s t i c band around t h e por t ion of it t h a t i s higher , and use i t s p o s i t i o n t o a d j u s t t h e r u l e r s o it is l eve l , )

Then p u t f i v e p i n s on each s i d e . Add a s i x t h t o one side. Does t h e r u l e r move? Add f i v e more p i n s t o each side, SO

you have t e n on each s i d e . Add an e leven th t o one side. Does t h e r u l e r move? Continue t h i s procedure for fifteen and twenty p ins . j - - - Now hang your hook o r l i g h t weight c o n t a i n e r from t h e upper holes st each end of t h e r u l e r . Do the same thing, t e s t i n g t h e s e n s i t i v i t y t o d e t e c t t h e weight o f one p i n when these are zero, f i v e , t e n , f i f t e e n and twenty o t h e r p i n s already i n each con ta ine r .

You w i l l find t h a t i n one case, t h e s e n s i t i v i t y decreased g r e a t l y when many p i n s w e r e a l r eady on each con ta ine r . This

-- c h a r a c t e r i s t i c is use fu l when you want s t u d e n t s t o quickly compare o b j e c t s that are s p p r c x i ~ z t e l y the same weight wi th o t h e r objects t h a t are very d i f f e r e n t i n weigh<, such as being only h a l f as heavy. Too much s e n s i t i v i t y might make e v e r y o b j e c t seem d i f f e r e n t i n weight from every o t h e r object, and t h e students would get bogged down. Measuring t h e pota to cubes i n Part I of Preserving Food b y Drying is an a c t i v i t y bhere t h e balances purposeful ly should n o t be very s e n s i t i v e .

Now make one more ho le i n t h e c e n t e r of t h e r u l e r , s o it looks as follows:

I n t h i s explanat ion , t h e weight o f t h e beam i s s t a y i n g t h e same - it is t h e weight of a r u l e r . I f you need t o make an extremely s e n s i t i v e balance, t h e same p r i n c i p l e s descr ibed here can be used with a l i g h t weight beam made from t h i n cardboard. Simi- l a r l y , if a more rugged balance is needed f o r heav ie r weights, a design us ing p a r t s of a tree could be made, similar t o t h e diagram a t t h e end of t h i s explanat ion .

NOW p u t t h e n a i l i n t h e new ho le you have made n e a r t h e edge of t h e r u l e r . F i r s t put it on the p i v o t with t h e ho le nea r t h e lower edge of t h e r u l e r . You w i l l s e e t h a t it does n o t balance when it is used t h i s way. This i s because t h e c e n t e r of g r a v i t y of t h e r u l e r i s above t h e p i v o t . The r u l e r tr ies t o f a l l t o a p o s i t i o n where i t s c e n t e r of g r a v i t y i s below t h e p ivo t .

Now p u t t h e r u l e r on t h e p i v o t s o t h e new hole (with a n a i l through it that rests on the edges of the tins) i s near t h e t o p edge of t h e r u l e r . Repeat t h e same procedure of t e s t i n g t h e s e n s i t i v i t y of t h e balance by p u t t i n g one p in on one side, when you have zero, f i v e , t en , f i f t e e n and twenty p i n s a l ready i n t h e con ta ine r s a t each end o f t h e beam.

You now have seen how t h e s e n s i t i v i t y v a r i e s according t o where you make the ho les a t each end, and the hole i n t h e c e n t e r that t h e p ivo t ing n a i l goes iz. Nc;x ysu will be ab le t o make a balance where you can des ign what t h e s e n s i t i v i t y w i l l be, even i f you use materials such a s shown i n t h e fol lowing diagram:

Sec t ion T. D E T E C T I N G CHANGES I N T E M P E R A T U R E W I T H OUT A THERMOMETER

* I n a number of t h e a c t i v i t i e s where an i n c r e a s e of tempera- t u r e t a k e s p lace , it can be f e l t with your hand. These are A c t i v i t i e s I-3B, I-4C, I - 4 C Fur ther S t u d y , I-5A and 1-10.

In s e v e r a l o t h e r a c t i v i t i e s , t h e i n c r e a s e s i n temperature can be noted t h e same way, b u t it would be d e s i r a b l e t o improve both measuring s k i l l s and understanding of t h e s i t u a t i o n s by making a somewhat more q u a n t i t a t i v e measurement. The approaches suggested here apply t o t h e s e a c t i v i t i e s : I-5B, 1-7, 1-7 F u r t h e r S t u d y , I - 8 B , I - 1 1 A , I - 1 1 B and 11-2.

I n t h e F u r t h e r S t u d y fo l lawing A c t i v i t y I - 3 A , a laboratory thermometer which can measure temperatures up t o 100' c is needed. This is a d i f f i c u l t requirement t o meet with i m - p rovised temperature measuring devices , b u t perhaps you can inven t one or l o c a t e an e x i s t i n g design t h a t i s easy t o make and works w e l l . I f you do, p l e a s e communicate it t o t h e Information Col lec t ion and Exchange o f f i c e . Also, p lease l e t us know about your s u c c e s s f u l o r unsuccessful a t tempts t o measure temperature i n any of t h e l e s s o n s .

I n many i n d u s t r i a l a p p l i c a t i o n s , temperatures are measured us ing p ieces o f m a t e r i a l t h a t m e l t a t known temperatures. Eor example, i n A c t i v i t y 1-7, t h r e e t i l e s a r e p laced i n t h e sun. They are a l l h o r i z o n t a l . One i s b lack , one i s e a r t h colored , and t h e o t h e r one i s white. On each t i l e , you could p u t a p i e c e of margarine and a p i e c e of wax. Whether both of t h e s e m e l t on each t i l e , and how long it t a k e s cou ld be noted. Maybe i n your l o c a l i t y , both of t h e s e m e l t t o o e a s i l y . Can you f i n d another m a t e r i a l t h a t melts a t a h i g h e r temperature?

*Th.e classroom a c t i v i t i e s r e f e r r e d t o here a r e those described i n Peace Corps ICE manual M10, Preserving Food by Dryinq: A Math-Science Teaching Manual.

The fol lowing device can measure smal l and medium changes of temperature.

a i r space Transparent i n k tube from Bic pen. Wash

ball n o t i n s p i r i t (alcohol) to remove a l l old ink.

Water w i t h a little coloring i n it. This part mus t

a l l be i n the place where temperature is being measured.

The air t r apped i n t h e tube expands as the temperature rises. Experiment with t h e s i z e of t h e a i r space. A small a i r space gives less s e n s i t i v i t y , b u t a h i g h e r temperature can be measured without the w a t e r s p i l l i n g o u t t h e end o f t h e tube. ~ h e ' r a n ~ e has an upper l i m i t near t h e b o i l i n g p o i n t of water because too much w a t e r vapor forms i n t h e a i r space. P o s i t i o n s along t h e tube can be marked, o r it can be glued t o a piece of paper, pasteboard, p l a s t i c o r wood, and t h a t can be marked.

The fo l lowing device is u s e f u l f o r measuring r e l a t i v e l y small changes in temperature. A i r i n t h e body of t h e pen expands t o move t h e co lo red water. A i r must be free t o leave or enter t h e tip. Water g e t t i n g i n it w i l l impair i t s opera t ion .

colored /* wa t ex \e -

Complete transparent B i c pen, except ball has been removed from the tip.

~ l l connections must be sea led , inc lud ing t h e s m a l l h o l e on the side of the pen. When the a i r i s warmed and expands, it pushes t h e co lo red w a t e r . It must n o t escape elsewhere. The whole device is s e n d i t i v e t o change o f temperature. E i t h e r t h e whole t h i n g should be put i n t h e p l a c e where temperature i s being measured, o r t h e same leng th must be used f o r a l l measurements which are t o be compared. I t a l s o responds t o your w a r m f ingers , and t h u s must be h e l d some other way.

h s you can see, t h e s e dev ices have some m e r i t , and w e a r e anxious t o h e a r o f your e f f o r t s t o use them. However, t hey also have l i m i t a t i o n s . Perhaps t h e y can be adapted i n some way t o become b e t t e r . - The cond i t ions of measurement i n t h e var ious a c t i v i t i e s a r e ,as follows:

--_ Activity Wet Amount of Temperature Calibration Temperature

or temperature present over of device too ho t to Dry change a large or needs numbered touch by hand

small area uniform for very long intervals

I-5b wet s l ight can be either no no

1-7 dry moderate to large large area no maybe

- -- - ~ - -

1-7 wet sncder ate large area Yes no

1-7 Further dry moderate large area Yes maybe Study to large

rr8b dry moderate large area no maybe to large

171 1 a depends on moderato size of

equipment

depends on Further very size of Study large equipment ---

Sect ion U. M A K I N G A SET OF W E I G H T S

Without a set of weights, an e q u a l a r m balance can be used t o s e e whether var ious o b j e c t s are equal i n weight o r not . This is done i n A c t i v i t y 1-6: where t h e equal arm balance shows t h a t i f one of t h e cubes is c u t i n t o s e v e r a l p ieces , t h e p i e c e s s t i l l weigh t h e same as t h e o t h e r cube t h a t was not c u t .

~f t h e o b j e c t s a r e t o be weighed with t h e equal arm balance, a s e t of weights i s needed. This i s necessary where t h e weight of a p i e c e of f r e s h food i s t o be compared wi th t h e weight of t h e s a m e p iece of food a f t e r it has been d r i e d . The equal a m balance can be used f o r weighing by p u t t i n g t h e p iece of food on one s i d e of t h e balance and by p u t t i n g enough weights on t h e o t h e r s i d e t o balance t h e food.

The set of weights should be based on some e a s i l y a v a i l a b l e o b j e c t s t h a t a l l weigh about t h e same. I n Section S, t h ings l i k e s t a p l e s , common p ins , and paper c l i p s a r e suggested f o r t e s t i n g t h e s e n s i t i v i t y of t h e balance. However, t h e s e a r e t o o l i g h t t o be use fu l f o r weighing t h e food p ieces . They a l s o have t h e disadvantage t h a t un less they a r e a l l bought from t h e same source, they may no t a l l have t h e same weight. Washers a l s o do no t make s u i t a b l e weights, because they a r e made f r o m s c r a p p i e c e s of s h e e t m e t a l , and al though the diameter may be t h e same, t h e th ickness v a r i e s tremendously.

Bo t t l e tops from Coca-Cola, Fanta and beer b o t t l e s are q u i t e uniform i n weight. These are probably t h e b e s t t h i n g s on which t o base your set a f weights. They have t h e added advan- t a g e of being ob ta inab le f o r f r e e .

The set of weights can c o n s i s t on ly of b o t t l e t o p s . For example, a piece of food might weigh 130 b o t t l e t o p s f r e s h and 47 b o t t l e - tops after being d r i e d . This g e t s t o be a l o t o f b o t t l e t o p s t o p i l e on t h e balance, however.

Somewhat heavier o b j e c t s t h a t are q u i t e uniform a r e b a t t e r i e s o f the kind used i n f l a s h l i g h t s and r ad ios . TQe weights may vary between b a t t e r i e s from d i f f e r e n t makers, b u t a l l b a t t e r i e s of a c e r t a i n type made by t h e same company should weigh about t h e same. Consider t h a t you have some small b a t t e r i e s t h a t each weigh 14 b o t t l e t o p s , and some l a r g e b a t t e r i e s t h a t each weigh 55 b o t t l e t o p s . To weigh t h e f r e s h food i n t h e example, t w o l a r g e b a t t e r i e s would equa l 110 b o t t l e t o p s , one small b a t t e r y would add 1 4 , and 6 b o t t l e t o p s would add t h e rest, t o reach t h e t o t a l o f 130 b o t t l e t o p s o f weight. To deigh t h e d r i e d fruit, t h r e e small b a t t e r i e s would equal 4 2 b o t t l e t o p s , and 5 b o t t l e t o p s would be added t o balance t h e f o o d ' s weight of 47 b o t t l e t o p s .

* Peace Corps ICE Mamal M10, Preserving Food by D r y i n 9 , p. 51

Objects such a s these can be used to make sets -of weights suitable for all the food drying activities in t h i s book.

-

Larqe Battery

small ~attery

Bottletops

Total wr;i<ht_ ) (bnttletops)

-----.-----

Fresh ? o ~ d Objects on Object - - Equivalent balance weight weight

2 X 5 5 = 110

1 X 14 = 14

6 X 1 = 6

130

- Dried Food Objects on Object - Equivalent - balance weight weight

0 X 55 = 0

3 X 14 = 4 2

5 X 1 - - 5

-- - - - .- -- - -

Section V. CONVERSIONS BETWEEN METRIC, BRITISH AND AMERICAN WEIGETI'S AND MEASURES

These conversions have been rounded t o produce values that are easy t o work with and t o remember. However, they are a l l within ' 2 percent of the exact values .

LENGTH

Metric

1 centimeter =

1 decimeter - -

1 meter - - 1 kilometer - -

British and American

1 inch - - 1 foot =

1 yard =

AREA - i4etric --

1 square decimeter =

1 square meter - - 1 square meter - -

1 hectare


1 square inch - -

1 square foot =

1 square yard - -

1 acre - -


41 10 inch

4 inches

40 inches

518 mile

Metric

2.5 centimeters

3 decimeters

9/10 meter

1.6 kilometer

British and American - 15.5 square inches

10.8 square feet

1.2 square yards

2.5 acres

Metric

6.5 square centimeters

9.3 square decimeters

516 square meter

4/ 10 hectare

VOLUME

Metric Br i t i sh American

100 m i l l i l i t e r s - - 3.5 ounces - - 3.4 ounces

500 m i l l i l i t e r s - - 17.5 ounces - - 17.0 ounces

1 l i t e r = 0.88 quart - 1.06 quart -

5 l i t e r s - - 1.1 gallons - - 1 .3 gallons

Br i t i sh Metric Arne r i can Metric

1 cubic inch = 16.4 m i l l i l i t e r s 1 cu6ic inch I = 16.4 m l

1 ounce = 28.0 m i l l i l i t e r s 1 ounce I = 30.0 m l

5 ounces (k p i n t ) = 140.0 m i l l i l i t e r s 4 ounces (k cup) =120.0 ml I 10 ounces (k p in t ) = 280.0 m i l l i l i t e r s 8 ounces (1 cup) ~ 2 4 0 . 0 m l

1 p in t (20 ounces) = 550.3 m i l l i l i t e r s 1 pint (16 ounces) ~ 4 8 0 . 0 m l I 1 quart (40 ounces = 1.1 l i t e r s I 1 quart (32 ounces) -960.0 m l

1 gallon (4 quar ts) = 4 . 5 Liters I 1 gallon ( 4 quar ts) = 3.8 1

Miscellaneous Metric

1 bo t t l e top (Coca-Cola, e t c . ) = 3.5 m i l l i l i t e r s

1 usual teaspoon = 4 t o 5 m i l l i l i ~ e r s

1 measuring teaspoon = 5 m i l l i l i t e r s

1 tablespoon, ea t ing = 8 t o 10 m i l l i l i t e r s

1 tablespoon, se rv ins = 14 t o 16 m i l l i l i t e r s

1 measuring tablespoon = 15 m i l l i l i t e r s

Note: 40 Bri t ish omces - I British (ImperiaZ) quart, and 32 American ounces = 1 American quart. Amhe ounces are ailmost the same s i z e but t h i s r ek t iansh ip creates a difference of about 20 percent i n the s i z e of pints, quarts and gattorts betaeen Brit ish and Americarc measurement of uoZwne.

Metric

10 'grams

100 grams

1 kilogram


1 ounce

1 pound

10 pounds

WEIGHT


- - 7 /20 ounce

3.5 ounces

2.2 pounds

Metric

- - 2 8 grams

- - 450 grams

= 4.5 kilograms

Note: The Brit-ish and American tozits of wweight sllown &ova are the ones in common use, the "Avoirdupois system, which has 16 ounces i n a pomd. Another system e&sts in both Britain and America, the rtapothecaryrr or "troy system. Its pound, which equuts about 370 grams, contains 12 omces, Ifhis system is onZy used i n certain spec ia l t i es .

I n c e 1961 when the Peace Corps vas created, more than 80,000 U.S, c i t i r ens have served 40 Volunteerr i n developirrg countries, l iv ing and working among the people of the ahfrd N r l d a8 colleague8 and c o - ~ r l r s . Today 6000 PCVe are involved i n progrme derigned t o h e l p rtrengthcn local capecity t o address much fundmental concern8 sa food production, water Supply, energy developnent, aut r i t ion and health education and reforemtation.

I a r e t M l l e r Ihrppe. Director Everett Alvrrez, Jr. Deputy Director R lchrd B. Abell, Inrector, OEfice of Programming and h'aining Coordination

Peace ODrps averserr offlceo:

BELIZE - P.0. &X 487 Belize U t y

M L A Y S I A BFXCKEUES 177 Jalan &_la Uuda B x 564

Suva Kuala ~unr~ur - Victoria

GABON - BP 2098 Librevil le

SIERRA LEONe R i v a t e Hail 818 Freetown Co tonou

DOTSUANA P.O. b x 93 Gaborone

GAMBIA, The P.0. &X 582 llrnjul

GHANA - P.0. BOX 5796 Accra (North) Snipan, k r h n a #Pabane

Irlandr

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BONDIJRAS REPAL - Apartado Portal P.O. Ibx 613

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I[ENYA - #))ZINICAN REPUBLIC P.0. b~ 30518 o w - &artado Portal Nairobi P.O. sox 966

1414 h r c a t

PNUA nu GUINEA m s u -- C/O h e r i c a n 5 b & r r y 6, h e . IPuir Port Moreaby Era i l l e

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