water cycles

We can see dew on the leaves of plants early in the morning. Which of the following best describes the formation of dew?

• The water vapour in the air condenses

• The leaves give out water

• The sun evaporates the water from the ground

• The cold air interacts with leaves

Heat is gained when ___________________.

• Water boils

• ice melts

• water freezes

Which of the following best explains why bubbles appear at the mouth of the glass tubing when the flask is heated gently?

• Air in the flask contracts

• Air in the flask expands

• Water in the basin expands

• WAter in the basin contracts

Which of the following results in the water droplets appearing on the surface of the beaker?

• Condensation of water vapour in the air

• The melting of ice inside the beaker

• Water in the beaker loses heat to the surroundings

• Water leaking from the beaker

John notices "clouds" above the spout of the kettle when water boils. What are the "clouds" made of?

• Tiny droplets of water

• Hot air

• Water vapour

• Steam

Which of the following statements show the process of evaporation taking place?

• A dog sticking out its tongue on a hot day

• Sweat from our skin cools our body when its hot

• A saucer of sea water left to dry leaving behind salt crystals

• Our spectacle turns misty when we step out of an air-conditioned room

Under which conditions does evaporation occur at a faster rate?

• A larger surface area

• A sunny day

• A dry day

• A windy day

Which of the following statements about water is true?

• Water covers less than half of the earth's surface

• Water can exist in three states

• Changes in the state of water are reversible

• The state of water depends on the temperature

What may happen when chemical waste that contains mercury from a factory flows in a river?

• All the organisms in the river are not affected

• Living organisms will be poisoned by the chemicals

• Living organisms increase in population

• The nutrients in the water increase and help the plants grow well

Which of the following are sources of water?

• rivers

• Wells

• Ponds

• Lakes