Paper 2

Sample Answer-Question 8 (2009)

8 (a) Diagram 8.1 shows two different containers, J and K. The grasshoppers in both containers are similar.

(i) State one difference between the grasshoppers in containers J and K after two days.

    Ans : The grasshopper in J died but the grasshopper in K is still alive.

              (must state both grasshopper J and K)

(ii) What inference can be made based on the situation in containers J and K?

     Ans : The grasshopper depends on air/oxygen to live.

(b) Diagram 8.2 shows four similar candles being covered by four containers, K, L, M and N, of different sizes.

(i) In Table below, record the time taken for the candle in container M to extinguish.

    Ans : 11 s

(ii) Predict the time taken for the candle in container N to extinguish.

    Ans : 11.1 – 60s

(iii) Based on the data in Table 8.1, draw a bar chart to show the time taken for the candle to extinguish in each container.

    Ans : Transfer all points(1 m)

             Bar same width (1 m)

(c) Based on the bar chart drawn in 8(b)(iii), state the relationship between the size of containers and the time taken for the candles to extinguish.

    Ans : The bigger the size of the container, the longer the time taken for the candle to extinguish.

(d) State the responding variable in this experiment.

     Ans : Time //time to extinguish

(e) Predict the time taken for the candle in container K to extinguish if the air in the container is replaced with exhaled air.

    Ans : < 5 s //shorter time (Reject : 0 sec)

(f) State the operational definition for combustion.

    Ans : Combustion is the time taken for the candle to extinguish