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SECTION A(20 marks)

1. D 11. B

2. C 12. B

3. C 13. B

4. A 14. B

5. B 15. D

6. A 16. A

7. B 17. D

8. C 18. B

9. B 19. A

10. C 20. C

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SECTION B(40 marks)

Answerall questions.

1. In teaching basic science process skills on observing, a teacher asked thestudents to observe cockroaches.

(a) State two possible purposes of asking the students to observe thecockroaches.

(i) to teach the students to use different senses to observe

(ii) to teach the students about quantitative and qualitative observations

(b) (i) Does merely looking at cockroaches sufficient to teach thenecessary observation skills to the students?

No.(ii) State a reason for your answer in b(i).

Because the students should also be taught to doobservation involving objects or phenomena that undergo

physical or chemical changes Observation involving process: before, during and after the

process

(c) Name three scientific instruments to be used in this activity.

Ruler, weighing machine, magnifying glass

2. A science teacher plans to inculcate communicating skills in an activity toinvestigate the effect of weight on a rubber band.

(a) What is the meaning of communicating in science?

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Using words or graphic symbols such table, graphs, figures, or models todescribe an action, object or even.

(b) State three communicating skills that can be cultivated in this activity.

to construct a table from the data collected

to use graph to show the relationship between the weight andexpansion of rubber band

to state the relationship between the weight and expansion ofrubber band

(c) Why are the communicating skills important to the primary school students?

Because through the communicating skills acquired, the students discover

new ways to construct their thinking

3. A science class was given a task to investigate whether the length of time acandle burns in a glass jar is affected by the volume of the jar.

(a) What are the units of measurement involved in this activity?

second (s)centimeter cube (cm3)

(b) State three measurement and using number skills in this activity.

to use a stopwatch correctly

to construct a table from the data collected to record the data in correct units

(c) How the students can improve the accuracy of length of time taken?find the average from a few readings

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4. A science teacher plans to teach the topic Ohms Law. At the same time, theteacher wants to inculcate inferring skills in the lesson.

(a) What is inferring?

Using past experiences or previously collected data to draw conclusionsand make explanations of events

(b) Describe three indicators that can be used to determine whether a studenthas acquired the inferring skills in the activity.

able to draw conclusion that voltage or resistance in the circuitaffects the amount of current flows in the circuit

able to draw conclusion that the heat produced in the circuit camefrom the electric energy

able to draw conclusion that the reading in the ammeter is due tothe flow of current in the circuit

(c) What should the teacher do once the students have acquired the inferringskills stated in (b)?

Ask the students to make suitable prediction

SECTION C

(40 marks)

Answer any two questions.

1. All the scientific experiments begin with identifying and controlling variables.Therefore, it is important for the primary school students to understand andmaster these skills in their learning of science.

(a) Describe your understanding of variables in science by giving appropriateexamples.

Variables are conditions/factors involved in the experiment, and may differ from oneexperiment to another

3 types of variables: independent, manipulated, and controlled variables

The independent, or manipulated variable, is a factor that is intentionally variedby the experimenter

Example:

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John is going to use 25g., 50g., 100g., 250g., 500g. of sugar in his experiment

The dependent, or responding variable, is the factor that may change as a resultof changes made in the independent variable

Example:

In this case, it would be the size of the loaf of bread

Controlled variables are all the factors that the experimenter attempts to keep thesame

Example:They might include:Other ingredients to the bread recipe, oven used, rise time, brand of ingredients,cooking time, type of pan used, air temperature and humidity where the breadwas rising, oven temperature, age of the yeast, etc.

(b) (i) Define the meaning of controlling variables in science experiments.

Controlling variables means to fix or eliminate variables orcontributing factors in order to clearly identify the relationshipbetween an independent variable and a dependent variable

(ii) Explain how will you control the variables in an experiment to testthe hypothesis that the more light plants receive, the taller theplants will grow.

Only 2 variables should be allowed to change or vary,amount of light (MV) and height of plant (RV)

All other factors must be kept the sameThe constants in this experiment include:

all the plants are the same size

the same soil in each pot

watered at the same time each day

given the same amount of water

kept in the same place

2. The following set of data was collected in an investigation to determine the effectof planting time on pumpkins weight.

Time After Planting(weeks)

Average Weight Of Pumpkin(kg)

2 0

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7 0

9 112 9

16 15

18 22

(a) Construct a graph for these data.

(kg)

Graph: Average Weight Of Pumpkins versus Time After Planting

(kg)

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Correct:

(b) Interpret the graph drawn in (a).

Formation of pumpkin begins after 8.8 weeks of planting

After that, the weight of pumpkin increases almost proportionally tothe time

The growth rate of pumpkin is about 2.5 kg/week

(c) From the graph, estimate:

(i) the weight of pumpkin 10 weeks after its formation.

22 kg

(ii) the time needed for pumpkin to increase 10 kg in its weight.

4 weeks

3. An experiment to determine the relationship between quantity of fertilizerdissolved in water and the growth rate of young seedlings is planned.

(a) Construct a suitable hypothesis for the experiment stated above.

As the amount of fertilizer increases, the growth rate of plantincreases

or

As the amount of fertilizer increases, the growth rate of plantdecreases

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(b) Describe the procedures to test the hypothesis constructed in (a).

Prepare 5 same pots of young seedlings

Measure 5 gram of fertilizer in a container

Pour 250 ml distilled water into the container of 5 gram fertilizer

Stir the mixture until all the fertilizer dissolved in the water

Pour the solution into the pot with young seedlings Repeat the procedure with different amount of fertilizer, eg.: 10, 15,

and 20 grams for different pots of young seedlings

Measure the height of every young seedlings in each pot after 7days

Calculate the growth rate of seedlings in each pot: Growth rate =(Average Height of Young Seedlings) / (Number of Days)

Compare the growth rate for each pot to determine whether toreject or accept the hypothesis