Question

what do these two changes have in common? mixing sand and gravel ice melting in a cup select all that apply. both are only physical changes. both are chemical changes. both are caused by heating. both are caused by cooling.

Explanation:

• Physical vs. Chemical Changes:
• A physical change is a change in which no new substances are formed. Mixing sand and gravel is a physical change as it just combines two substances without altering their chemical composition. Ice melting is also a physical change (change of state from solid to liquid) with no new substance formed. A chemical change results in new substances. Since neither of these is a chemical change, the option “Both are only physical changes” is correct and “Both are chemical changes” is wrong.
• Cause Analysis:
• Mixing sand and gravel is not caused by heating or cooling. It's a simple physical combination. Ice melting is caused by heating (absorbing heat to change state). So neither “Both are caused by heating” nor “Both are caused by cooling” is correct as a commonality for both changes.

Answer:

A. Both are only physical changes.