P5 Science SA1 2023 — Raffles Girls

The male and female human reproductive systems are shown below. (a) Name the parts labelled B and E. (b) Explain why part B is important in human reproduction. (c) In which part of the reproductive systems, A, B, C, D or E, does fertilization take place?

Study the cross-section of the insect-pollinated flower below. (a) Draw an arrow (→) in the diagram above to show how pollination takes place. (b) State the function of the part labelled L in the flower. (c) Based on the diagram above, will the fruit developed from the flower have one or many seeds? Give a reason for your answer.

Mavis found fruit P and fruit Q which were of the same mass. She wanted to carry out an experiment to investigate if the fruits were dispersed by water. (a) Identify the following variables: (i) Independent variable: (ii) Dependent variable: (b) The list below shows some of the steps Mavis would take when conducting the experiment. Put a tick (√) next to the step Mavis should include in her experiment. Leave the box empty if the step is not required in her experiment. Steps to consider: Drop fruit from a height of 1.5 m in front of a fan; Check if the fruit is edible; Cut open fruit to see if it was filled with liquid; Put the fruit in a pail of water and observe. (c) State one other variable in the experiment that Mavis must keep the same to ensure a fair test. (d) State a physical characteristic that the fruit has to help it dispersed by water.

Alexis poured 200 ml of boiling water into two identical containers, A and B, as shown below. Then the containers were left on a table in a room with a constant temperature of 29 °C. She recorded the time taken for the boiling water to cool to 40 °C in the table shown below (Container A: 50 min, Container B: 50 min). (a) Give a reason why the temperature of water in both containers, A and B, decreased. Alexis conducted a second experiment by inserting two rods made of Material X and Y into Container A and B respectively as shown below. She then plotted the change in the temperature of the boiling water in both containers over time as shown in the graph (water in Container A cools faster than in Container B). (b) Which material, X or Y, would be more suitable to be made into a container to keep drinks cold? Explain your answer. (c) What would be the temperature of the water in the containers A and B after ten hours? Give a reason for your answer. Alexis had a bimetallic strip made of metals P and Q as shown below. After heating, the strip bends as shown below (the strip curves upwards with metal Q (hatched) on the inside of the curve and metal P on the outside). (d) Give a reason for the observation above.

Andy placed a cup of drink on a table in a room of temperature 25 °C. After two minutes, Andy saw water droplets as shown in the diagram below. (a) Based on his observation, is the temperature of Andy's drink higher, lower or same as the room temperature? Explain your answer. The following diagram shows the set-up Andy used to collect fresh water from sea water. He placed the set-ups in the garden on a sunny day for seven hours. (b) Explain how fresh water could be collected using the set-up above. Andy repeated the experiment using a similar set-up, placing crushed ice on the plastic sheet as shown below. (c) Explain why Andy was able to collect more water using set-up R.

Jean wanted to find out how the exposed surface area of ice cube(s) would affect the decrease in the temperature of water. She filled identical cups, P, Q and R, with the same volume of water and added the same mass of ice as shown below (P has one large ice cube, Q has two medium ice cubes, R has many small ice cubes). She recorded the temperature of the water at the start of the experiment and after ten minutes as shown in the table below (P: start 35 °C, after 10 min 30 °C; Q: start 35 °C, after 10 min ____; R: start 35 °C, after 10 min 20 °C). (a) Write the temperature of water in cup Q after ten minutes in the box above. (b) Based on the results above, how does the size of the ice cube affect the decrease in temperature of water? Jean tried to dry two identical wet trousers, X and Y, as shown in the diagram below. She folded trousers X before hanging it to dry but not trousers Y. (c) Which one of the trousers, X or Y, will dry faster? Explain.