Description: Step: Lay the car flat, put an appropriate amount of alcohol in cup, and put in absorbent cotton. Fill a metal cylinder with about 1/3 of warm water and plug it tightly with stopper. Place the mouth of the metal tube facing the wall to conduct the experiment. Heat the water in the cylinder. When the pressure of the water vapors reaches a certain value, it will rush out of the rubber stopper and the car will move backward. Educational Tool: The Recoil Motion Demonstrator is an essential learning tool for physics education, providing a hands-experience to students for understanding the Law of Conservation of Momentum. Quality Material: Made from premium quality materials, this Dynamic Recoil Reverses Thrust Force and Counterforce is designed to withstand repeated use in a classroom setting. Easy to Use: This product is suitable for demonstration experiments on recoil movement in high school physics teaching. Which is designed with simplicity in minds, making it easy for both teachers and students to use. Enhances Learning Experience: Stimulates curiosity and interest in scientific exploration. It helps students visualize complex physics concepts, making learning interactive and engaging. Size Chart: 9.5x6.5cm/3.74x2.56inch Package Includes: 1pcs Teaching instrument Note: 1. The amount of alcohol should be appropriate to avoid fire when the trolley is moving backwards.2. During the experiment, the metal cylinder should not be pointed at people to prevent the rubber stopper from rushing out or the boiling water from splashing and scalding people.3. After the experiment, you need to wipe off the alcohol on the trolley and pour out the water in the metal cylinder.