1, the straw that penetrates the potato. This experiment uses the power of air to pierce potatoes through the power of air. We plug one end of the straw with our fingers, and the only air outlet in the straw is the end where the potato is stuck.

2. Balance birds. The balance bird is balanced because the center of gravity moves forward from the middle of the bird's body to the bird's mouth after adding the paper clip, which means that the actual center of gravity of the whole bird is below the tip of the mouth.

3. Running laps. In this experiment, we stretch the rubber band and then loosen the bottom. Because the elastic rubber band shrinks upward and returns to its original state, there is static friction between the iron ring and the rubber band, which will rise together with the rubber band. We cover the shorter and shorter rubber bands with our hands. From the visual point of view, it seems that the iron ring rises by itself.

4. Be smart with paper money. Using the principle of inertia, the paper money is knocked off quickly with your fingers. Inertia is an inherent property of an object, which can keep the object in a static or fast linear motion state and resist the change of motion state.

When withdrawing money quickly, when the acceleration of paper money movement is greater than the maximum acceleration provided by friction, the movement speed of coins and bottles is relatively backward, and gravity and inertia will not move.

5. Pine cones and climate. In order to spread the seeds better, the pinecones will close when the rainy season comes. Only when the rainy season is over and the weather is dry and the spores in the pine cone can fly a longer distance will it open. Through this experiment, we can observe the changes of pine cones in different environments.