If you were standing at sea level measuring the air pressure, you would actually be measuring the air's friction speed weight moisture

Boiling water, pencil being sharpened, freezing water.

Explanation: Physical change is the change in which there is no rearrangement of atoms and there is change in size or shape of the substance.

Chemical change is the change in which there is rearrangement of atoms and the new substances get formed.

Boiling water only changes the phase from liquid to gas and thus is a physical change.

Pencil on being sharpened only gets smaller in size and thus is a physical change.

exploding dynamite would result into formation of new substances and hence a chemical change.

Freezing water only changes the phase from liquid to solid and thus is a physical change.

Rotting cheese would result in formation of new substances and hence a chemical change.