It is convenient to water the flowers with a watering can. Many children also use it to make rainbows. In fact, the principle of watering can is very simple. It is also convenient to make a manual watering can according to the principle. Just use an empty plastic bottle and punch a few holes in the bottle cap to make a watering can. The rainbow sprayed by the watering can is formed by the scattering and reflection of small water droplets formed by sunlight in the water mist. Using this principle, you can see the rainbow by spraying water fog with your back to the sun on a sunny day. Let's see how to make a watering can. First, how to do the manual watering can?

Sprinklers mainly use atmospheric pressure to achieve the effect of spraying water. After understanding the principle, we can make a watering can out of plastic bottles, which is very convenient and inexpensive. The manufacturing method of manual watering can is as follows:

1. Prepare an empty plastic bottle, such as a coke bottle or a mineral water bottle. There is no special requirement on the size of the bottle.

2. Take off the bottle cap of the plastic bottle, and use an awl or other sharp objects to evenly pierce several small holes on the bottle cap as the water outlet hole of the watering can. The more holes, the smaller the aperture, and the better the water spraying effect.

3. After tying the hole, fill the plastic bottle with water, tighten the bottle cap, turn the bottle upside down, and pinch the middle of the bottle with your hand, and the water will be sprayed out from the small hole.

It should be noted that if the bottle body of the self-made watering can is too large, or the aperture of the hole punched in the bottle cap is too large, it may lead to insufficient pressure and cannot spray too far. Pay attention when making.

Second, how does the watering can spray rainbow?

Many friends used spray bottles and the like to make rainbows when they were young, which were very beautiful. In fact, this is a physical phenomenon, so how to spray a rainbow with a spray bottle?

The physical principle of spraying a rainbow with a watering can is that the rainbow is formed by the scattering and reflection of sunlight on small round water droplets in the air, and the water mist sprayed by the watering can is formed by gathering many tiny spherical water droplets. When sunlight hits the water droplets, it will be incident at different angles at the same time, and will also be reflected at different angles in the water droplets. The reflection of 40-42 degrees is relatively strong, and the rainbow we see will be formed.

According to this principle, when we stand with our backs to the sun on a sunny day, we can see the rainbow by spraying water mist from the watering can.