KEM GEMILANG 2014 : SCIENCE FORM 3 MODULE 1 1. A group of students carry out the experiment shown below to study how different factors will affect the

absorption of heat from the sun by water in some containers.

Experiment: Same size of containers with different surfaces, A, B, C and D containing same amount of water are put under the shade or right under the sunlight.

Results: After a couple of hours, the temperature of water in the containers is measured. The results are shown in the table below.

Container Temperature of waterA increases from 25°C to 27°CB increases from 25°C to 26°CC increases from 25°C to 29°CD increases from 25°C to ?°C

Answer the following questions.

(a) Complete the table below to indicate if the results obtained from the following pairs of containers can be compared fairly and your reasons for making the decisions. [4 marks]

Containers Can they be compared

fairly?

Reasons

A and B

A and C

B and C

C and D

(b) What conclusion can you draw from the results obtained from containers A and B?

Figure 1.1

[1 mark](c) What conclusion can you draw from the results obtained from containers A and C?

[1 mark]

(d) (i) The final temperature of water in container D is not given. Do you expect the temperature to be higher or lower than 290C?

[1 mark](ii) Explain your answer in (i).

[1 mark]

(e) The diagram below shows a car parked under the hot sun.

Figure 1.2

Relate the use of a shinning shading board with the findings in this experiment.

[2 marks]

2. Figure 2.1 below shows the exchange of gases between human beings and the surrounding and Figure 2.2 shows the exchange of gases between plants and the surroundings.

(a) When do human beings and plants take in carbon dioxide and oxygen?

(i) Human beings _________________________________________________

(ii) Plants _________________________________________________[2 marks]

(b) What is the use of carbon dioxide and oxygen in human body?

(i) Carbon dioxide _______________________________________________________

(ii) Oxygen _______________________________________________________[2 marks]

(c) When do(es) the reaction(s) you mention in (b) take place in human body?

(i) Carbon dioxide _______________________________________________________

(ii) Oxygen _______________________________________________________[2 marks]

(d) Compare the composition of inhaled air and exhaled air

[4 marks](e) What is the use of carbon dioxide and oxygen in plants?

(i) Carbon dioxide _______________________________________________________

(ii) Oxygen _______________________________________________________

[2 marks]

Figure 2.1 Figure 2.2

(f) When do(es) the reaction(s) you mention in (e) take place in plants?

(i) Carbon dioxide _______________________________________________________

(ii) Oxygen _______________________________________________________[2 marks]

(g) Explain why it is important to plant more trees in our country?

[3 marks][

(h) Water plants are put in two samples of water, P and Q, in two separate beakers. Water P is collected from a river. Water Q is tap water which is boiled for about 10 minutes first and then allowed to cool to room temperature. They are shown in the diagram below.

(i) If both beakers are exposed to sunlight, what difference would you expect to see?

___________________________________________________________________________

___________________________________________________________________________[1 mark]

(ii) Explain the difference in observation.

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________[ 3 marks]

3. Four food chains given below are found in a farm ecosystem.

Paddy grasshopper frog eagle

Paddy rat eagle

Paddy bird eagle

Paddy rat snake eagle

(a) Using the space below, construct a food web to show how all the four food chains are interrelated.

Paddy

eagle[4 marks]

(b) Name and describe the interaction that exist between the grasshopper and the rabbit.

_________________________________________________________________________________

_________________________________________________________________________________[2 marks]

(c) Do you think the following statement are correct? Give reasons for your answer.

(i) All green plants are producers.

______________________________________________________________________________

______________________________________________________________________________[2 marks]

(ii) The secondary consumer in a food chain can be a carnivore or an omnivore

______________________________________________________________________________

______________________________________________________________________________[2 marks]

(iii) Other than paddy, name another organism that can play the role of paddy in this ecosystem..

___________________________________________________________________________[1 mark]

(d) Farmers consider snake a harmful animal because its bite may be poisonous and want to get rid of all the snakes in the farm. If all the snakes are killed, predict what will happen to the rats and paddy.

_________________________________________________________________________________

_________________________________________________________________________________

__________________________________________________________________________________[2 marks]

(e) Figure 3.1 shows a pyramid of numbers that represent one of the food chains given above and the amount of energy transferred between the various levels. .

Eagles20 kJ

Frog200 kJ

Grasshopper2000 kJ

Paddy20 000 kJ

(i) How does the number of organisms change as we move from the lowest levels up to the highest level?

_____________________________________________________________________________[1 mark]

(ii) How many percent of energy is transferred from the organism to the next higher level?

______________________________________________________________________________[1 mark

}

3. (a) Diagram 3.1 shows a giraffe standing in two different positions at different times.

Position A Position B Diagram 3.1

i. Based on your observation in Diagram 3.1, state the difference in stability of giraffe when it is standing in position A and B.

__________________________________________________________________________

__________________________________________________________________________[ 1 mark ]

ii. What inference can be made based on the standing position of A and B in Diagram 3.1 ?

__________________________________________________________________________

__________________________________________________________________________[ 1 mark ]

iii. State one hypothesis based on your observation in Diagram 3.1 __________________________________________________________________________

__________________________________________________________________________[ 1 mark ]

(b) The student carried out an experiment to investigate the situations in Diagram 3.1. Diagram 3.2 shows the experiment set-up of the apparatus used.

6 cm 5 cm

Diagram 3.2

The student takes the following steps.

Step 1 : Model T is placed in front of a table fan. The distance between

model T and the fan is 120 cm.

Step 2 : The fan is switched on at the speed of 1 and a stopwatch is set on at

the same time.

Step 3. : The time taken for model T to fall is recorded.

Step 4 : Steps 1 to 3 are repeated for models U and V.

i. In the spaces provided record the time taken for models T , U and V to fall.

The time taken for the model T to fall

= ________________ ( s )

10 cm

8 cm

10 cm

9 cm

The time taken for the model U to fall

= ________________ ( s )

The time taken for the model V to fall

= ________________ ( s )

[ 3 marks ]

ii. Complete Table 3.1 by recording the base area of models T , U and V the

stopwatch readings.

Table 3.1 [ 1 mark]

(c) State the variables involved in this experiment .

Manipulated variable

Responding variable

[ 2 marks ]

Model T U V

Base area ( cm2 )

Stopwatch readings (s )

(d) Based on the readings in Table 3.1 , draw bar chart to show the time taken for the models to fall.

[ 2 marks ]

(e) Based on the experiment, state the relationship between the base area of an object and its stability.

_________________________________________________________________________________

_________________________________________________________________________________

[ 1 mark ]

Time taken for the model to fall (s )

T U V Model

Pendulum bob

One complete swing

Diagram 4.1

Length of pendulum

4. A student carried out an experiment to study the relationship between the length of a pendulum and the time taken for the pendulum to make one complete swing. The apparatus set-up is shown in Diagram 4.1

The procedures to carry out the experiment are as follows:

S 1 A pendulum bob is tied to a string and hung on a retort stand as shown in Figure 2S 2 The time taken for the pendulum to make 10 complete swings is taken.S 3 The experiment is repeated with different lengths of the pendulum string.S 4 The results are tabulated in Table 4.1

(a) State the variables involved in this experiment.

Manipulated variable:

Responding variable:

Fixed variable:

[3 marks]

(b) Table 1 shows the results of the experiment. Calculate the time taken for one complete swing and complete Table 4.1

Length of the pendulum (cm)

Time taken for 10 complete swings (s)

Time taken for 1 complete swing (s)

10 8.0

20 10.0

30 12.0

40 14.0

50 16.0

60 18.0

TABLE 4.1[3 marks]

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

Time taken for one oscillation (s)

2.0

Length of pendulum (cm)

10 20 30 40 50 60 70

(c) Using Table 4.1, draw a line graph to show the relationship between the length of the pendulum and the time taken for one complete swing.

(d) Based on the graph, what can be said about the time taken for the pendulum to make one complete swing?

______________________________________________________________________________

(e) What can you infer from the experiment?

_____________________________________________________________________________

(f) From the graph, predict the time taken for the pendulum to make one complete swing if the length of the pendulum is 70 cm.

______________________________________________________________

(g) State the relationship between the length of the pendulum and the time taken to make one complete swing.

______________________________________________________________

______________________________________________________________

5. Diagram 5.1, shows an experiment to see how temperature affects the amount of sugar that will dissolve in a beaker of water until it becomes saturated. Each beaker contains the samevolume of distilled water at different temperature and the mixture is stirred at the same rate.

Diagram 5.1

Diagram 5.1(a) In the experiment, name:

(i) the solute : ___________________________________

(ii) the solvent : ___________________________________ [2 marks]

(b) Suggest a hypothesis for this experiment._____________________________________________________________________

_____________________________________________________________________[1mark]

(c) State the variables involved in the experiment.

(i) manipulated variable

(ii) responding variables

(iii) constant variables

[3marks]

The amount of sugar dissolved in each beaker is recorded as shown in Table 5.1

Temperature (oC) Amount of sugar dissolved(g)20 1540 4560 7580 105100 135

Table 5.1 (d) Based on table 5.1, plot a graph to show the amount of sugar dissolved against

temperature.

[2marks]

(e) Based on the graph, find amount of sugar dissolved when the temperature of the water in the beaker is at 70oC.____________________________________________________________________

[1mark]

(f) What is the relationship between manipulated variable and responding variable?

____________________________________________________________________

____________________________________________________________________[1mark]

(g) What inference can you make from this experiment?_____________________________________________________________________[1mark](h) Give one factor that affects solubility._____________________________________________________________________[1mark]

4.The Story of Thomas Alva Edison

“Thomas Alva Edison once noticed that when electricity flowed through a piece of iron wire, the iron wire became red hot. The wire glowed brightly, but not bright enough to light a room. When he used a thinner piece of iron wire and allowed electricity to pass through, the wire glowed. But he wanted greater brightness. He tried other metals. Finally he discovered that a thin piece of tungsten wire could actually glow so bright that it could light up a room.

But he also saw the glow did not last long. After a few minutes, the wire had burned to ashes. He wondered why. He knew that oxygen is needed in burning. Using a machine he pumped out all the air inside the bulb. He enclosed the tungsten wire in what he thought was already an oxygen-free bulb. He tested the bulb. The bulb glowed longer than before. What he wanted was a bulb to glow longer and give light steadily, so he continued with his experiment.

He pumped out all the air or gases inside the tube and test the bulb. He repeated this steps over and over again getting several bulbs busted in the process. He did not lose hope. He continued with the experiment until finally the tungsten wire glowed steadily and brighter. He knew that he succeeded. He invented the incandescent light bulb.

Source: Science and Technology I, SEDP Series, DECS pp. 3-4.

(a) What was the problem of Thomas Alva Edison in his experiment?(b)