~ PSLE SCIENCE PG. 128 ~

Answer for questions:

5a) No. It does not matter if Liquid P is a conductor of electricity as the metal clips are connected to Material Q. The circuit is already closed if material Q is an electrical conductor.

b) Yes. Q has got to be a conductor of electricity in order for it to be a closed circuit, as electricity needs to flow through the circuit for the metal clips are connected to the container instead of liquid P. 



6a) 5 object X.

b) No. An object that is less than 3 cm in height cannot block the light source and thus the light will still reach the light sensor. Only object greater than 3cm can block the light from the light source.

c) Place the object X nearer to each other on the belt




7a) Light can be absorbed.

b) She is walking away form the lamp during period Y. A longer shadow is cast when Daisy is moving further away from the lamp as more amount of light is blocked than when she is nearer to the lamp.

c)  The time intervals for period X and period Y are the same but the change in length of the shadow is less for period X than period Y. THus, Ken can conclude that Daisy walked at a slower speed during period X.




8ai) South-Pole
ii) North-Pole

b) A magnet must have two distinct poles, North and South, at each end of the magnet. But if Darren's method is used, the steel bar will not have these two distinct poles at ends X and Y.