This is an incomplete question, here is a complete question.
Which change is the best example of a physical change?
1) a cookie baking
2) a paper burning
3) ice cream melting
4) a nail rusting
Answer : the correct option is, (3) ice cream melting
Step-by-step explanation :
Chemical change : It is a change where changes occurs in the chemical composition and thus resulting in the formation of new compound or substance. It is an irreversible reaction.
The indication of chemical changes are :
Formation of gas bubbles.
Formation of precipitate.
Change in color.
Change in temperature.
Change in volume.
Change in smell or taste.
Evolution of heat, light and sound.
Physical change : It is a change in which shape and size of a substance changes. In this there is no change in the chemical composition of the substance and no new substance is forming. It is a reversible reaction.
The indication of chemical changes are :
Change in shape.
Change in form.
Change in size.
Change in phase.
1) a cookie baking
2) a paper burning
4) a nail rusting
Option 1, 2 and 4 are a chemical change because changes takes place in the chemical composition and form new compound.
3) ice cream melting : It is a physical change because only changes takes place in the phase from solid phase to liquid phase.
Hence, the best example of a physical change is, ice cream melting.