This temperature-controlled fan is relatively simple to assemble and can help children understand simple physics and circuit knowledge. It is a good electronic starter kit and scientific enlightenment kit. Suitable for children to assemble themselves, can train children's hands-on ability, let children combine with textbook knowledge in play. Replace the switch with a temperature sensor, immerse the temperature sensor in hot water (can also be replaced by a lighter or an alcohol lamp), so that the temperature of the temperature sensor is greater than 40 ° c, the circuit is connected, and the small fan starts to operate.