The change of size or shape of a substance is a ( ) change.

chemical
nuclear
physical
phase
atomic

It's a physical change. A physical change is when an object can return back to it's previous state, etc. If it was a chemical change, the object would not be able to return back to it's previous shape, state or size, etc.

Physical

Explanation:

chemical

Means its structure has completely changed- it is not the same hunk of stuff that it was before, at least atomically.

nuclear

Only deals with (mainly) radioactive elements, whether it be something changing them or it changing that something.

Physical-

Deals with visible changes, such as shape, size, color, or state of matter.

Phase-

A phase is where a material is at right now.

Atomic-

Same with chemical, this would mean a whole change in element.

nuclear fission produces elements that are heavier than helium.

the elements that are used in nuclear fission and their products are much heavier than helium.