Number of things. Box A Box B. Time

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2 Section B (44 marks) For questions 29 to 41, write your answers in this booklet. The number of marks available is shown in brackets [ ] at the end of each question or part question. 29. Kelvin set up two boxes, A and B. He placed some living things in one box and an equal number of non-living things in another box. Both boxes were provided with air, food and water. He counted the number of things in both boxes every week and drew the graph as shown below. Number of things Box A Box B Week 0 Week 1 Week 2 Time (a) Based on the graph above, which box contained the living things and which box contained the non-living things? Fill in the blanks below using A and B. Living things: Box Non-living things: Box (b) State the characteristic of living things that you use to arrive at your answer in (a). 2 22

3 30. Sabrina conducted an experiment by preparing two set-ups, C and D, using two identical containers that were filled with an equal amount of the same type of soil. She put a boiled papaya seed and an unboiled papaya seed in the soil as shown below. One month later, she noticed that the seed in set-up D had germinated but not the one in set-up C. boiled papaya seed beaker soil unboiled papaya seed Set-up C Set-up D (a) What was the aim of Sabrina s experiment? (b) List two other variables that Sabrina must keep the same in order to ensure that the test is fair. [2] (i) (ii) 3 23

4 31. Mrs Lee counted the number of wild plants, X, Y and Z, on a piece of land. After a few months, she looked at the same piece of land again. Her observations are as shown below. Plant X Plant Y river Plant Z Direction of river flow First observation After a few months State the methods of dispersal for the seeds of the plants, X, Y and Z, and describe the characteristic of the fruit of the three plants that aids them in their dispersal. [3] Plant Method of dispersal Characteristic of the fruit (a) X (b) Y (c) Z 24 3

5 32. Diagrams 1 and 2 below show the reproductive organs of a flowering plant and human respectively. A B E Diagram 1 T S U F G Diagram 2 (a) Write the letter that represents the reproductive part of the human that has a similar function as the flowering plant stated in the table below. Plant Reproductive Part Human Reproductive Part A B 1 25

6 32. The diagram below shows one of the human reproductive organs given in Diagram 2. Tube W was cut and tied due to a medical condition. uncut tube X tube W cut and tied (b) Explain clearly why fertilisation is still possible after tube W is cut and tied. 1 26

7 33. Billy placed a healthy plant that has pale green leaves in a basin of red-coloured water with nutrients for its growth as shown in the diagram below. redcoloured water with nutrients (a) What would Billy observe about the leaves after a day? (b) Explain the reason for the observation he made in (a). 2 27

8 33. Billy was asked by his Science teacher to predict what would happen to the stem if the outer ring of the stem at P was removed. His teacher showed him both the side view and cross-sectional view of the stem as shown below. Side view of the stem at P redcoloured water with nutrients P P outer ring of stem removed non-coloured part inner part of the stem remained outer ring of the stem removed coloured part Cross-sectional view of the stem at P Billy drew his prediction of the stem as shown below but he was told by his Science teacher that his diagram was incorrectly drawn. outer ring of stem removed swollen lower part (c) Explain why his Science teacher said so. [2] 28 2

9 34. Mr Tan conducted an experiment to investigate the digestion of jelly cubes as shown in the diagram below. He placed a jelly cube into a test tube containing liquid X as shown in set-up A. Liquid X contains a substance that aids in the digestion of food. test tube test tube liquid X liquid X cold water Set-up A Set-up B Set-up C Set-up D 5 g of jelly cube and 20 cm 3 of liquid X 5 g of jelly cube cut into 4 pieces and 20 cm 3 of liquid X 5 g of jelly cube cut into 8 pieces and 20 cm 3 of liquid X 5 g of jelly cube and 20 cm 3 of cold water Mr Tan then repeated the same process for another two identical jelly cubes, each cut into different number of pieces. He recorded the time taken for the jelly cubes to be completely broken down into simpler substances in the table below. Number of pieces the jelly cube was cut into Time taken for the jelly to be completely broken down into simpler substances (hours) Set-up A Set-up B Set-up C (a) Based on the data shown in the table above, why did the time taken for the jelly cube to be completely broken down into simpler substances decrease with the increase in the number of pieces the jelly cube was cut into? (b) What does liquid X represent in the human digestive system? 2 29

10 34. Mr Tan discovered that the jelly cube in set-up D as shown in the diagram on page 30 was not broken down at the end of the experiment. (c) What was the purpose of having set-up D? (d) Liquid X stops working when it has been boiled. To test this hypothesis, Mr Tan needs to use a fifth test-tube, together with all the set-ups used in the earlier experiment. What does he have to put into the fifth test tube to carry out the investigation? 2 30

11 35. A group of pupils set up an experiment in the diagram as shown below to investigate whose lungs can hold the most amount of air, that is, who has the largest lung capacity. plastic tube 2-litre plastic bottle basin water Each pupil took a deep breath and exhaled as much as he or she could into the plastic tube. The graph below shows the results they obtained. Amount of water left in the bottle ( ml) Amount of water left in the bottle (ml) Ali Bob Carol Denny (a) Arrange in order, starting with the pupil having the smallest lung capacity to the pupil with the largest lung capacity. Pupil with the smallest lung capacity Pupil with the largest lung capacity (b) Explain how the above set-up is able to measure their lung capacity. [2] 31 3

12 36. Fred wanted to buy a fishing rod. He tested three fishing rods made of three different materials, S, T and U, all of which are of the same size. He bent the fishing rods, one at a time, using a weight. The diagram below shows the distance, d, moved by the rods when the weight was placed on one end of each of the rods. handle rod table ruler d 10 kg weight He then measured the distance which the rod bent. Using the same weight, he repeated his investigation with materials T and U and recorded his results in the table below. Material Distance d (cm) S 7 T 15 U 30 (a) What property of the materials was Fred investigating? (b) What was the changed variable of the experiment as shown above? (c) Based on the results shown above, what could Fred conclude about materials S, T and U? 3 32

13 37. Ming Cheng conducted an experiment in the Science laboratory with a room temperature of 28 C using two similar-sized cups that are made of different materials. He filled both cups with the same amount of tap water at a temperature of 25 C and placed them each into a basin of hot water at 90 C as shown below. Cup X thermometer Cup Y tap water at 25 C hot water at 90 C tap water at 25 C Ming Cheng then used a thermometer to measure and record the temperature of water inside each cup for ten minutes. The results were plotted in the graph as shown below. Temperature of water inside the container ( C) 25 Cup Y Cup X Time (min) (a) Based on the results shown in the graph above, explain why there was an increase in the temperature of water in each cup. (b) Explain the difference in the results obtained for cup X and cup Y. 33 2

14 37. (c) What would happen to the temperature of water in the cups and basins after leaving the set-up in the Science laboratory for several hours? (d) If Ming Cheng wanted to keep his chocolate milk cold for a longer period of time, which cup, X or Y, would he choose to use? Explain your choice. (e) Suggest one way on how Ming Cheng can measure the readings of the temperature of water in each cup more accurately. 3 34

15 38. Leena wanted to compare the magnetic strength of four magnets, A, B, C and D, which were of the same size. She set up the experiment below with the same pole of each magnet facing the plastic tray and observed the number of steel pins that were attracted by each magnet. A C steel pin B D plastic tray (a) Leena concluded that magnet B and magnet D had the same magnetic strength as both of them attracted the same number of steel pins. Do you agree with her? Explain your answer. [2] (b) Suggest what Leena should do to her set-up so that she would be able to find out which magnet had the strongest magnetic strength. (c) Using the same set-up as shown in the diagram above, Leena replaced magnet D with another magnet X of the same size. State two possible observations that could be made if magnet X has a stronger magnetic strength than magnet D. [2] Observation 1: Observation 2: 35 5

16 39. Ravitha set up an experiment as shown below to find out how the amount of light recorded on the datalogger was affected by the number of sheets of paper that she used. black box paper datalogger torchlight light sensor She repeated her experiment by increasing the number of sheets of identical paper used. She recorded her results in the table below. Number of Amount of light detected (lux) sheets of paper (a) (a) Fill in the value for the amount of light that could have been detected by the light sensor in the table shown above. (b) Ravitha carried out the experiment with no paper in the beginning. Explain why. (c) Give a reason for the results obtained when five sheets of paper were used. (d) What was the purpose of using the black box? 36 4

17 40. Doreen set up the apparatus for two set-ups, A and B, at the same location in the Science laboratory as shown below. Both of the set-ups were similar. The water in each of the containers was at room temperature. energy source energy source electric fan switch electric fan switch wind direction wind direction 1000 ml of water 1000 ml of water Container X Container Y Set-up A Set-up B Doreen then turned on both electric fans at the same time and recorded the amount of water left in both containers in the table as shown below. Amount of water left in container X (ml) Amount of water left in container Y (ml) (a) Based on the information given above, why did the water level in containers X and Y decrease, after the switch was switched on for 30 minutes? (b) Give a possible reason of why the amount of water left in container Y is less than that of container X. Go on to the next page) 2 37

18 40. Uncle Tan installed water mist systems outside his open-air cafe to reduce the temperature of the surrounding air. Tiny water droplets in the form of a mist from the water mist systems are produced as shown below. mist (c) Uncle Tan received feedback from his customers that the surrounding air felt cooler after the water mist systems were installed. Explain how the water mist systems helped to cool the surrounding air. Go on to the next page) 1 38

19 41. Uncle Ho bought some crispy fried spring rolls from the hawker centre and noticed that some holes were punched on the styrofoam box as shown below. holes styrofoam box (a) How do the holes on the styrofoam box help to keep the spring rolls crispy? [2] _ The next day, Uncle Ho bought a pizza home for dinner and realized that it was packed in a paper box instead of a plastic or styrofoam box. The paper box also did not have holes on it. clip pizza paper box (b) Uncle Ho ate the pizza and realized that it was not soggy. Explain why. Setter: Mdm Sum W.F. END OF PAPER 39 3

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