Sid discovers that liquids can freeze into solid ice and can melt right back into liquid over time.
Sid wakes up and discovers that his ice pops melted! This sticky situation leads him to ask," Why do things have to melt?" After investigating at school, Sid learns that if liquids don't stay in a really cold place, they slowly melt over time. He also discovers that liquids can freeze into solid ice and then melt right back into liquid.