Batteries, rotating coils, small wind turbines, electric boats and automatic flower watering devices circulate on the track.
These five little inventions are relatively simple and they apply all the physics knowledge learned in middle school. It is very suitable for high school students with practical ability to achieve. Let's explain how to make these three little inventions.
1. Batteries traveling in orbit
First of all, the tools we need to prepare are batteries, magnets and copper coils. Attach small magnets of the same polarity (N or S) to the positive and negative terminals of the battery. Next, place the prepared battery into the copper coil. At this time, you will find that the battery continues to shuttle back and forth in the copper coil.
The small magnets are the key point of this experiment. They not only generatent a magnetic field, but also act as conductors, connecting the copper coil to the positive and negative poles of the battery, even if there is current. generated in the copper coil, at that time An energized copper coil generates a magnetic field according to the laws of electromagnetic induction and the right-hand rule.
2. Small electric boat
In this invention we have to prepare batteries, motors, windmills, mineral water bottles, small wood chips, wires and adhesive tape . Cut the mineral water bottle horizontally, then place a small piece of wood in the middle of the halved mineral water bottle and secure it with tape. Then install the windmill and motor together, then attach the motor to the small piece of wood and stick it with tape. The direction of the windmill is towards the stern of the boat (the tail of the mineral water bottlee).
Then use wires to connect the battery and the motor. At this time, the motor drives the windmill, and the windmill generates wind power, and the boat will move forward when placed in the water.
3. Automatic flower watering device
The principle of automatic flower watering device is very simple, using the principle of atmospheric pressure. First we need to prepare a bottle of water, then two straws. Poke two holes in the water bottle, just big enough to insert a straw.
Then cut the straw to a suitable length, insert the straw into the water bottle with the hole drilled, and then place the straw near the water storage tray at the bottom of the flower pot. When the water level in the water storage bin drops to one of the two straws used as air inlet, the other straw will suck water from the water bottle and water automatically.nt the flowers.
Drill two small holes in the film box and insert the axle. Insert two small pieces of straw into the small holes of the film box, wrap the enameled wire around it, scrape the insulating paint from the enameled wire at both ends of the coil with a knife, wrap it around the two pins of the light. -a light emitting diode, rotate the shaft and the magnet. As the coil rotates, the magnetic flux in the coil changes, producing an electric current.