Question

Which real-world scenarios below represent physical changes? Check all that apply.

running a car engine

exploding fireworks

mixing water and powdered drink mix

combining oil and vinegar to make salad dressing

taking aspirin for a headache

diluting bleach with water

digesting Thanksgiving dinner

spreading peanut butter on bread

Answer 1

Physical changes:
- mixing water and powdered drink mix (dissolving — same substances, just dispersed)
- combining oil and vinegar to make salad dressing (physical mixture/emulsion)
- diluting bleach with water (dilution — same chemical, lower concentration)
- spreading peanut butter on bread (change in shape/placement, no new substance)

Not physical (chemical changes):
- running a car engine (fuel combusts)
- exploding fireworks (chemical reactions produce new substances/light/heat)
- taking aspirin for a headache (metabolism/chemical reaction in the body)
- digesting Thanksgiving dinner (enzymatic breakdown → new substances)