Please answer the following questions about states of matter and changes of state.

Here are the answers to the questions about states of matter:

1. Identify the state of materials in each of the pictures.

• A: The material is in a solid state.
• B: The drink is in a liquid state.
• C: The water in the kettle is in a liquid state, and the steam is in a gaseous state.
• D: The ruler is in a solid state.
• E: The water being poured is in a liquid state.

2. Which changes listed below are examples of melting and which are examples of solidifying? Give a reason for each answer.

• a. You have a piece of chocolate in your pocket on a hot day.
  • Change: Melting
  • Reason: The chocolate changes from a solid to a liquid due to an increase in temperature (heat from your body/hot day).
• b. You put jelly in the fridge to set.
  • Change: Solidifying
  • Reason: The jelly changes from a liquid to a solid due to a decrease in temperature (cooling in the fridge).
• c. You put butter in a pan so that you can fry an egg.
  • Change: Melting
  • Reason: The butter changes from a solid to a liquid due to an increase in temperature (heat from the pan).

3. Identify the change of state in the following parts of the water cycle:

• a. clouds form
  • Change: Condensation (water vapor to liquid water droplets)
• b. snow forms
  • Change: Freezing/Solidification (water vapor to ice crystals or liquid water to ice)
• c. water vapour forms
  • Change: Evaporation (liquid water to water vapor)
• d. snow becomes liquid water.
  • Change: Melting (solid snow to liquid water)

Use the words to complete the sentences.
a. The states of substances are solid, liquid and gas.
b. Solids keep their shape.
c. Liquids take the shape of the container they are in.
d. Gases have no shape, but they take up space.
e. When we heat solids, they melt and become liquid.
f. When liquids are heated they evaporate to form gases.
g. When gases cool they condense to form liquids.
h. When liquids cool, they solidify and become solid.