premise: heat is a kind of heat energy sent2: a car engine is a source of heat sent3: heat energy can change the state of matter sent4: ice is a kind of solid sent5: liquid is a kind of state of matter sent6: melting means a substance changes from a solid into a liquid by increasing heat energy sent7: solid is a kind of state of matter.
hypothesis: the negatively-charged plastic strip and negatively-charged piece of cloth will repel each other