Any experiment can be used.. even from the daily life.

Please clarify your question

This should be under Homework, and you should TRY to do it first yourself.
Look around you. Mix flour and water, or bleach and ammonia (don't do that), pour vinegar on weeds, open fizzy drinks in space (after you buy a spot on a space ship), dissect some frogs, burn your polyester clothes flat or vertical, I can think of thousands without stopping. Take it from there. You need to discuss how theorizing in your head has pros and cons vs experimenting and then theorizing. That's your job.

Drink coffee and don't empty it out a fourth of a cup of it that's left. Watch how it changes. See what the liquid looks like in a week.