SA1 Revision 2 2012 Answer Notes

SA1 REVISION 2 2012

P6 Science

Booklet A

What to do

Understand the concept for each

question.

Underline the key words (question).

Understand the explanations for each

question.

Write down the correct answer as

correction.

Question 1 – Answer (1)

Concept:

Classification of plants

Key words (Question)

classify

Explanation

Tomato and love grass are dispersed by animals.

Coconut and pong pong are dispersed by water.

Pong pong and love grass are inedible plants.

Tomato and coconut are edible plants.


Concept:

Classification of materials

Explanation


Concept:

Life cycle of butterfly


Stage X, Stage Y

Explanation

Caterpillar moults a

number of times

Pupa is the stage where

it does not eat at all


Concept:

Seed dispersal


most likely

Explanation

Plant S – found near the sea, so most likely

dispersed by water.

Plant T – found near each other, so most likely

dispersed by splitting.

Plant U – found scattered all over the island, so

most likely dispersed by animals.


Concept:

Hereditary (passing down of characteristic traits)


adopted, most likely

Explanation

Since both Mr and Mrs Tng have double eyelids,

it is not likely for their children to have single

eyelid. Thus, Arnold is most likely the adopted

child.


Concept:

Reproduction of plants


most likely

Explanation

W – ferns reproduce from spores

X – Bryophyllum is able to

reproduce from leaves

Y – Water chestnut is an

underground stem

Z – Heliconia reproduce from

suckers

bryophyllum

Water chestnut

heliconia


Concept:

Water cycle


Water cycle

Explanation


Concept:

Environment


same amount, same amount, different, find out

Explanation

The water level drops because water is able to

flow and occupy the air spaces.


Concept:

Water boiling


Most likely, true

Explanation

A is false – different amount of water means the water will

boil at different times since the amount of heat supplied is

the same.

B is false – both have 2 burners, thus heat energy is the

same.

C is true – boiling temperature is always 100oC no matter

the amount of water.

D is false – same reason as C


Concept:

Function of the stomata in plants


Layer of cooking oil on both surfaces, died

Explanation

Since the stomata is blocked by the oil, it cannot

take in carbon dioxide (for photosynthesis) and

oxygen (for respiration).

Since oil is transparent, light can still pass

through.

Since oil is not an insulator of heat, warmth can

still pass through.


Concept:

Carbon dioxide is taken in during photosynthesis and

given out during respiration.


Amount of carbon dioxide, 12 midnight to 12 noon

Explanation

At night, photosynthesis does not occur (due to the

lack of light), therefore carbon dioxide level will be

high.

In the daytime, photosynthesis occurs, thus carbon

dioxide level will drop.


Concept:

Blood in humans


Blood, helps

Explanation

One of the function of blood is to transport

nutrients from the small intestine to all parts of the

body as well as to carry waste to the rectum.

Blood also carries oxygen (from lungs) and carbon

dioxide (to lungs).


Concept:

Heart rate


heartbeat

Explanation

Playing soccer will cause his heart rate to

increase the most.

Resting will lower his heart rate

Walking will increase his heart rate again but not

as high as playing soccer.


Concept:

Plant cells and its parts


Structures, all

Explanation

All plant cells have cell wall, cytoplasm and cell

membrane.

Not all plant cells have chloroplasts (e.g. root

cells) since only the leaves make food.


Concept:

Cell division (every cell divides itself into 2)


Every 15 seconds, 128

Explanation

Cell Count Time (seconds)

8 45

16 60

32 75

64 90

128 105


Concept:

Cell parts and function


true

Explanation

A is true – cell Z cannot make food as it does not have

chloroplast.

B is false – all cells can reproduce (all living things can

reproduce)

C is true – Cell Z does not have cell wall

D is true – Since cell Z does not have cell wall it must be an

animal cell.


Concept:

Electricity


X, blow

Explanation

when a bulb

blows, it forms

an open circuit


Concept:

Electricity conductors


Conductors of electricity

Explanation

Pencil lead is a conductor of electricity but not a

good one (thus the light produced is dim)

Plastic ruler and glass fibre is not a conductor of

electricity (thus no light produced)

Steel nail is a good conductor of electricity (thus

very bright light produced by bulb)


Concept:

Electrical circuit


false

Explanation

A is false – Set up Y is a series circuit

B is false – When batteries are arranged in series, it will

have more electrical energy as compared to a parallel

circuit, thus Y will be brighter.

C is true – When a bulb in series blows, the whole circuit

will fail to work.

D is false – When a bulb in parallel blows, the other bulbs

will continue to light up.


Concept:

Interaction of organisms (how one affect the other)


rapidly

Explanation

A will happen – Water hyacinth is a floating plant, if there are too

many, they will cover the surface of the river and block sunlight

from reaching the submerged plants (thus these submerged

plants cannot photosynthesize and produce oxygen.)

B will happen – The water hyacinth will create obstacles for the

boats to travel.

C will happen – Sunlight blocked preventing submerged plants

from making food (same reason as A)


Concept:

Photosynthesis of plants


Most adapted, hot and dry

Explanation

P is more adapted to survive in hot and dry

space as it is able to retain the most amount of

water.


Concept:

Food web (how change in one organism affects the

others)


Changes, D increases

Explanation

more predators

more foodmore predators

less

organisms

eating


Concept:

Environment – overcrowding, fair test


overcrowding

Explanation

Variable to change – size of pot

Variable to keep the same – Number of seeds

and type of soil


Concept:

Forces


true

Explanation

A is true – Gravitational force acts from a distance

B is true – Magnets only exert magnetic force on magnetic

objects

C is true – Weight is due to gravitational force acting on it

D is false – (common misconception) An object remains

stationary because frictional force is acting on it, otherwise

it will start moving.


Concept:

Magnets with stronger magnetic force is able to attract pins from a

longer distance


Strings of different length, true

Explanation

1. False – Although B attracted the most pins, it is also the nearest to

the pins

2. False – Although C attracted the least number of pins, it is the

furthest away from the pins, thus its magnetic force is not the

weakest

3. True – D and A attracted the same number of pins, but since D is

nearer to the pins, D’s magnetic force is weaker than A’s

4. False – same reason as (3)


Concept:

Extension of the spring is proportional to the mass of

the load


Original length, 8 cm, extension, 90g

Explanation

Every 10 g causes the length of spring to increase by 2

cm

Therefore, 90 g 26 cm (length of spring)

Thus extention 26 – 8 = 18


Concept:

Hardness of metals


Descending order of hardness

Explanation

A material is hard if it is able to scratch another

material

Y is hardest can scratch W, X and Z

W is 2nd hardest can scratch X and Z

Z is 3rd hardest can scratch X

X is softest cannot scratch any of the 3


Concept:

Light and shadow


Smaller shadow

Explanation

The nearer an object to the screen the smaller the

shadow

When you move the light source away from the

object, the shadow becomes smaller as well


Concept:

Heat gain, heat loss – Heat travels from hot to cold


Cold milk, hot water, correct

Explanation

A is incorrect – cold milk gains heat from the hot

water

B is correct – the hot water loses heat to the cold

milk, thus the temperature will drop

C is correct – the mug is cooler than the hot water,

thus it gains heat

D is incorrect – the hot water loses heat to the cold


Concept: Heat travels

Key words (Question) Irrelevant

Explanation1. A is relevant – this experiment shows that heat travels

through matter

2. B is irrelevant – whether matter expends when heated does not affect the outcome of this experiment

3. C is irrelevant – this experiment is to investigate whether air, water or metal is a better conductor of heat

4. D is relevant - this experiment is to investigate whether air, water or metal is a better conductor of heat

Booklet B

What to do

Understand the concept for each

question.

Underline the key words (question).

Write down the key words (answer) for

each question (that you did not get full

marks) as correction.

Question 31

Key Concept:

Classification of materials

Key Words or Phrases

Question Answer

a) Suggest,

heading

Natural Materials

b) Wrongly

classfied, explain

Silk, silkworm

Silk comes from an animal (0m) (not specific enough)

Question 32

Key Concept:

(a) Seed germination, (b) life cycle of animal


Question Answer

a) Tick T, NPTT, F, F

b) How many

stages

4 stages

c) How many days,

adult

11 days

Question 33

Key Concept:

Water does not have definite shape


Question Answer

a) Reason, overflow Gaps in sand, water can

occupy the space

b) Property Does not have definite

shape

Question 34a

Key Concept:

Testing for presence of starch


Question Answer

i) Which, dark

blue

Cell B

ii) Reason Chloroplast, make food

Question 34b

Key Concept:

Cell division (we grow because our cells are

dividing)

Key Words or PhrasesQuestion Answer

i) Size, explain,

wrong

Cell division cause increase in

height

ii) State, wrong Replacement of damaged cells

Question 35

Key Concept:

Factors that affect the survival of an organism


Question Answer

a) Complete, graphSee next slide

b) State 2 factors,

increase, deaths,

September

1. Sudden change in

temperature

2. Predators introduced

3. Adult guppy ate smaller

guppy

4. Water pollution

Question 36

Key Concept:

Environment – soil erosion (Plants hold the soil

together to prevent soil erosion)


Question Answer

a) Observed More soil in drain Y than X

b) Reason No grass (prevent soil

erosion)

c) Hill resort, apply Grow grasshttp://youtu.be/1D1V-t3UTHA

http://youtu.be/1D1V-t3UTHA




Question 37

Key Concept:

Forces – Gravitational force


Question Answer

a) What, force Gravitational force

b) Who, easier Ben

c) Explain Moving load downwards, same

direction as gravity

Question 38

Key Concept:

Extension of spring


Question Answer

a) Line graph

See next slide

b) Relationship The greater the mass of the weights

hung on the spring balance, the

greater the extension of the spring

Question 39

Key Concept:

Electromagnet


Question Answer

a) value of x, reason 0o,, no battery to turn rod into

electromagnet.

b) Explain, moved

away

Steel rod is now electromagnet,

iron thumbtack attracted to steel rod

Question 40

Key Concept:

Light and shadow


Question Answer

a) Light can pass

through

Identify, suggest

Soya Sause – Q (translucent)

Cooking oil – R

Mineral water – S (transparent)

Black coffee / dark ink – T

(opaque)

b) bases, aligned,

draw, shadow

Question 41

Key Concept:

Water - boiling


Question Answer

a) How, boiling

point

Temperature reach 100oC

b) Right, white

cloud, steam,

explain

No. Steam is gaseous state,

cannot be seen

Question 42

Key Concept:

Heat transfer | Cold contracts

Important – Coldness cannot travel. Heat

travels from hot to cold. Heat from rod travels

to ice.

Key Words or PhrasesQuestion Answer

a) Explain, cool end S Rod is good conductor of heat,

coldness transferred

b) Another change Contracts

c) Increased gradually

to 20oC, explain

Gain heat from surroundings

Question 43

Key Concept:

Heat expands


Question Answer

a) Why, open Lid expanded

b) Explain Gain heat from warm water

Question 44

Key Concept:

Heat expands


Question Answer

a) What, after

some time

Stopper pop out

b) Explain Air in flask expanded when

heated, force stopper out

Technology

SA1 Revision 2 2012 Answer Notes