Okay we are gonna use A iPhone to a old telephone so the telephone can only receive calls and call other people that it but say with the iPhone you can call the person and receive calls you can text you can video chat you can get emails you can have apps to entertain you you can have pictures and music you can have a ringtone and and text tones
Dissolving doe not indicate or guarantee a chemical change. Most of the time it is a physical change.
Unchanged solid in a liquid does not even indicate any change.
Solid floating on top of liquid does not indicate any change, physical or chemical.
When a mixture creates a new compound (gas from mixing solid and liquid), there is a chemical change.
A controlled variable is not changed throughout an experiment. It is there so that the other variables being tested on can be better understood.
