Question

1. which of the following substances is a magnetic material?

a aluminium
b carbon
c nickel
d zinc

1. which process do plants use to make their own food?

a germination
b photosynthesis
c respiration
d transpiration

1. which of the following animals is an amphibian?

a buffalo
b dove
c frog
d snake

1. a carpenter realises that the nails he stored in a can have rusted.

what should the carpenter have done to prevent the nails from rusting?
a oil the nails before storing them.
b poured soil into the storage can.
c poured water into the storage can.
d heat the nails before storing them.

the diagram below shows a solar still used to get clear water from muddy water contained in a bucket.
the clear water is collected into a cup.
use it to answer questions 5 and 6.

1. which change of state does the water on the plastic sheet under-go?

a boiling
b condensation
c freezing
d melting

Explanation:

🆕 New Concept Discovered: Phase Changes of Water
Gas turning into liquid droplets on a surface.

Step 1: Analyze the diagram

The diagram shows a solar still. Sun heat causes water from the muddy water in the bucket to evaporate, turning into water vapour (a gas).

Step 2: Identify the process on the plastic sheet

The water vapour rises and hits the cooler plastic sheet. When the warm gas touches the cooler surface, it loses heat and turns back into liquid water droplets.

Step 3: Match with the correct scientific term

The change of state from a gas (water vapour) to a liquid (water droplets) is called condensation.

• Boiling is liquid turning to gas at a specific boiling point.
• Condensation is gas turning to liquid.
• Freezing is liquid turning to solid.
• Melting is solid turning to liquid.

Answer:

B