Question

Pedro wants to create a chemical reaction between oil and water. He adds oil to a beaker of water and notices that the liquids do not mix. He then shakes the beaker and the drops of oil become suspended through the water for a few moments before returning to their separate layers.

Did Pedro succeed in creating a chemical change?

Yes, because the oil was evenly suspended.
Yes, because the solution was permanently changed.
No, because the oil only briefly mixed with the water.
No, because no new substances were formed.

Answer 1

No, because no new substances were formed.

Shaking produced a temporary physical mixture (an emulsion) with the oil dispersed through the water. That is a physical change — reversible separation back into layers — not a chemical change, which would produce new substances.