For example, if I put a crushed ping-pong ball in warm water, it will swell up after a while. Why is this? Because: the heated volume of air will become larger.
We can also use scientific knowledge to help our work and life. For example, water has three forms: solid, liquid and gas. When water is solid, it can turn into beautiful snowflakes, make ice cream and slide on the ice. When water is a gas, we can use it to generate electricity, and we can also use it on steam trains. When water is liquid, it can be used for drinking, cleaning and irrigating fields.
We should keep learning and exploring. Discover the mysteries of science and let scientific knowledge serve mankind!