Question

two materials which change their form forever when we heat them​

Answer 1

Answer:

in liquid

Explanation:

like iron and magnisium

Answer 2

Answer:

two materials which change their form forever when we heat them : water and crayons

Explanation:

The reason is -

• Water is a liquid at room temperature. If we cool it down, it changes into a solid – ice. If we heat it up, it changes into a gas – steam.
• When you heated up the solid crayons, you caused the crayons to melt. The solid crayons became a liquid and dripped down the paper. As the liquid crayons cooled, they became a solid again. This activity is an example of a reversible change, since the melting was reversed once the crayons had a chance to cool.