Sa1 revision 1 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 (2)

Concept:

Food web

Key words (Question)

removed, most negative impact

Explanation

Plants provide food for all living thing, thus they

will have the most negative impact when

removed.


Concept:

Food chain


NOT true

Explanation

1. True – grass gets energy from Sun to make food

2. True – Mynah gets energy from grasshopper when the mynah eats the grasshopper

3. True – Energy is passed from one organism to another in the food chain

4. NOT true – grasshopper does not make food


Concept:

Energy forms and Uses


incorrect

Explanation

1. Incorrect – energy is not created

2. Correct – solar means light

3. Correct – fossil fuels are organisms that was once

alive

4. Correct – Every organism gets its energy directly or

indrectly from the Sun.


Concept:

Friction


surface, distance travelled, true

Explanation

The greater the friction, the lesser the distance

travelled by the box.


Concept:

Force


NOT

Explanation

Mass is the amount of matter in an object. Weight

is the force acting on an object due to gravity.


Concept:

Photosynthesis


Successful production of oxygen

Explanation

Photosynthesis occurs only in the presence of

light.


Concept:

Energy conversion


Temperature rises considerably at point Z

Explanation

The kinetic energy (when the wire is bending

back and forth) is converted to heat energy.


Concept:

Elastic potential energy


5 turns, 10 turns, 15 turns, 20 turns

Explanation

The only variable that is changed is the number of

turns.


Concept:

Elastic spring force


Forces acting on the spring

Explanation

When you stretch a spring, the spring will exert a

force to try and pull it back to its original length.

When you compress a spring, the spring will

exert a force to try and push it back to its original

length.


Concept:

Volume and weight (matter)


Equal volume, different weights

Explanation

Volume is the amount of space an object takes

up.

Mass is the amount of matter in an object.

Therefore, although all 4 cubes have the same

volume, it does not mean they have the same

mass.


Concept:

Environment


Fungi

Explanation

Fungi grow in damp and warm places.


Concept:

Food web


Increase,

mynah population

Explanation

When mynah’s population increase, they will eat more ladybird and spider. Therefore if ladybird and spider’s population decreases, their prey (which are aphid and whitefly) will have less predator and thus increase in number.


Concept:

Adaptation


Function, drip tip

Explanation

The drip tip allows raindrops to run off quickly so

that it doesn’t collect on the leaves which will

block the stomata.


Concept:

Forces


Correct forces

Explanation

A – gravity acts from a distance and is always a pull

B – magnetic force acts from a distance and can be a pull (attraction) or a push (replusion)

C – friction acts only on contact and opposes the motion

D – push only acts when you are touching the object and it follows the motion


Concept:

Elastic potential energy


Number of turns, distance moved

Explanation

1 – true, based on graph

2 – false, 120 turns is needed to move 8 cm

3 – true, more number of turns, more energy stored, thus greater distance moved

4 – true, based on graph


Concept:

friction


Coated with liquid D, lubricating

Explanation

The aim of lubricating the moving parts of a

machine is to reduce friction to prevent wear and

tear. Thus, the liquid used must be able to reduce

friction the best.

The greater the distance moved by the wooden

block, the lesser the friction (or reduce the friction

the best).


Concept:

Environment – conditions for survival


Kill, more quickly

Explanation

Fair test – only the variable tested must change.

In this case, the variable that is changed is the

type of pesticide. All other variables must be kept

the same.


Concept:

Environment – interaction of organisms


Effectively remove the caterpillars

Explanation

Bird Q eats the most caterpillars (as number of

caterpillars left is the least) thus the most effective

to remove the caterpillars.


Concept:

Decomposers


decomposers

Explanation

Decomposers (e.g. bacteria) act on dead

organisms and animal waste to break them down

into simpler substances (e.g. nutrients) which is

absorbed by the plants.


Concept:

Environment – factors affecting survival


disease

Explanation

A disease will cause the drop in the number of

rabbits.


Concept: Environment – factors affecting survival

Key words (Question) Supported by the above data

Explanation1. Wrong – The presence of some earthworms indicate

earthworms can still survive in clayey soil.

2. Correct – The number of earthworms in garden soil is the greatest.

3. Wrong – there is not much moisture in sand and clayey soil.

4. Wrong – Since the numbers are all different, the earthworms do not thrive equally well.


Concept:

Matter – good conductor of heat and electricity


Good conductor, heat, electricity

Explanation

1. Book is a poor conductor of heat and electricity

2. Iron nail and key are made of metal which are good conductors of heat and electricity

3. Plastic comb is a poor conductor of heat and electricity

4. Rubber phone cover is a poor conductor of heat and electricity


Concept:

Water - Condensation


Cold room, tiny droplets

Explanation

Warm water vapour from the surrounding air

touches the cooler surface of the window, loses

heat and changes to water droplets.


Concept:

Cells


Does not belong

Explanation

Option 1 – 3 are animal cells, option 4 is a plant

cell since only plant cells have cell wall.


Concept:

Materials


Different materials

Explanation

Foam is the worst conductor of heat thus heat

from the cup will take the longest to escape to the

surrounding air, thus will contain the highest water

temperature after 1 hour.


Concept:

Human digestive system


Produce digestive juices

Explanation

Mouth, stomach and small intestines contains

digestive juices. Large intestines only absorbs

water, so no digestion takes place there.


Concept:

Plant parts


Plant parts

Explanation

They are all stems that store food.


Concept:

Electricity


Diagram 1, only bulb B lit up

Diagram 2, bulb A lit up but bulb B did not

Explanation

Since only the right bulb lights up, Y is the

conductor of electricity but X is not.


Concept:

Seed dispersal


hooks

Explanation

Seeds / fruits with hooks will be dispersed by

clinging onto the fur of animals.


Concept:

Reproduction


Reproduction, plants, animals

Explanation

1. Not true for animals

2. True for both

3. Not true for both

4. Animals does not have pollen grains

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:

Living things need air, food and water to survive.

Key Words or Phrases

Question Answer

a) Name, gas Oxygen

b) Explain,

dependent

Plants give out oxygen

during photosynthesis

c) Explain, dark room Lizard die because no

oxygen

Question 32

Key Concept:

Living things need air, food and water to survive.


Question Answer

a) Explain, survive Snails give carbon dioxide for

plants to make food

b) Explain, survive Plants give out oxygen during

photosynthesis needed by

snails

c) Explain, amount

of oxygen

Less oxygen as more snails

taking in oxygen

Question 33

Key Concept:

Photosynthesis requires sunlight, water and

carbon dioxide.


Question Answer

a) True, False, NPTT F, F, NPTT, NPTT

b) Suggest why,

unfavourable

Plants cannot receive

enough sunlight to make

foodNo sunlight Wrong concept as sheltered areas will still

get sunlight. It’s just not enough.

Question 34

Key Concept:

Different factors affect the local environment


Question Answer

a) Explain, Most loss

in massQ. Strong wind, evaporate

faster (Q does not have most exposed

surface area so large exposed surface area is

correct but not larger/largest exposed surface

area)

b) What, P dry faster Bigger (comparison) surfaced area

c) Suggest, dry

faster without

additional tools

Sunny place / less humid

Question 35

Key Concept:

Adaptations serve to enhance survival


Question Answer

a) Explain, change

colour, survive

Hide / blend with

surroundings to escape

predators

b) Which feature,

explain

Large ears. Large surface

area to allow animal to cool

down

Question 36

Key Concept:

A force can move a stationary object


Question Answer

a) State, change in

energy

GPE KE

b) State, which balls 3, 4, 5

c) Ball 1 heavier,

what change

Ball 5 – move further /

higher

http://www.walter-fendt.de/ph14e/ncradle.htm




Question 37

Key Concept:

Friction is an opposing force relative to the motion

of objects.

Test is on the size of wheel


Question Answer

a) Describe,

correct (fair

test)

Same plank

b) List, 2 mistakes Did not change size of wheel

Did not use same number of wooden

blocks

Question 38

Key Concept:

Forces causes the extension of springs

Compare mass of …


Question Answer

a) List, 2

variables

Same spring / Same scale pan

b) What,

measure,

greatest mass

Length of spring / Extension of

the spring

c) Explain, different extension / length /

Question 39

Key Concept:

Environmental conditions affects the habitat of

decomposers


Question Answer

a) What, min temp 25oC

b) State, conclusion The lower the temperature, the

slower the rate of decomposition

c) Suggest, one way,

Explain

Cold place / refrigerator

slow down the rate of

decomposition.

Question 40

Key Concept:

Plants, animals, fungi and microorganism forms

the 4 major groups in classification of living things

.

Key Words or PhrasesQuestion Answer

a) Explain, cake P not enough water / little water /

moisture

b) How, mould get

food

break down the cake into simpler

substances and absorb nutrients

c) Another similarity,

fungi, plants

respond to changes OR

grow and reproduce OR

cannot move freely from place to

place

Question 41

Key Concept:

Use of magnets to separate magnetic objects


Question Answer

a) Suggest,

separate

Use magnet to attract steel ball

bearings

b) Suggest,

another,

separate

Pour contents slowly into the

bucket of water. Cork pieces

will float

Question 42

Key Concept:

Temperature is a measurement of how hot or cold

an object is; heat is a form of energy.


Question Answer

a) Arrange S,Q,R,P

b) Explain, longer Greater volume of water at

100oC

Question 43

Key Concept:

An electrical system comprises of various

components.


Question Answer

a) Group Parallel – B, D, E

Series – A, C, F

Question 44

Key Concept:

Plants reproduce to ensure the suvival of their

own kind.

Key Words or PhrasesQuestion Answer

a) How many

months

5 months

b) Draw, Red

Clover

Education

Sa1 revision 1 2012 answer notes