What is a good scientific investigation topic that is easy? i have to do one but i don't have much

Explain in physical terms how a microwave oven works. what would happen when you put a conductor in the microwave oven? explain.

Heena wants to measure the volume of a ball that is 24 cm across. how should she set up her equation?

15. one purpose of the tread pattern on a tire is to a reduce tire wear. b. reduce traction c. allow water to flow away from the tire. d. look impressive.