You have four water samples at different temperatures. In which sample are the molecules vibrating at the fastest speed? A. water at 37°C B. water at 99°C
C. water at 99°F
D. water at 299K

Aphysical change is one that you can put in and remove like a ham sandwich. the stuff you put in there can be changem its not permanet. a chemical change is on that can't be change thats permanet. like when you make a cake and bake it. you can't get those ingredients back.