Tearing the piece of paper is one way to cause a physical change.When you tear paper, you change its shape and size — but it's still paper. Walang bagong substance na nabuo, kaya physical change lang ito, hindi chemical.
A physical change is a change in a physical property. Soaking, shredding, and crumpling paper are physical changes because they change the physical properties of the paper. They do not change the paper into something new.