1, water pipe seesaw

1. Hard plastic pipe with uniform material thickness, 3 cm in diameter and 40 cm in length; A soft wooden stick the thickness of a plastic pipe and 5 cm long; Two corks; Two thin sheets of iron; Sewing needle 2. Make a hacksaw, scissors, awl and knife. 3. Manufacturing step ① Cut the plastic pipe from the middle, divide it into two sections with equal length, and drill a small hole at the top and bottom of each section. Then connect the two pipes with a 5 cm long soft wooden stick and pass a sewing needle through the soft wooden stick.

(2) cutting the thin iron sheet into two brackets and two figures, and fixing the figures on both sides of the plastic pipe; (3) Fill the pipe with water and plug it with a cork, put the sewing needle on the bracket and adjust the balance of the pipe on the bracket.

At this time, water flows out rhythmically from the small hole under the tube. At this time, as long as one end of the seesaw is pressed, the seesaw will automatically tilt upward and fall, and the water on both sides will drop out in turn until all the water drops out. Attention, please put it in the basin to prevent the water from wetting the table. Think about why it goes up and down automatically.

2. Staircar

It is very difficult to carry heavy things upstairs. Inspired by the action of the puppy going upstairs, I designed a car that can carry heavy things upstairs.

When carrying heavy objects upstairs, first push the front wheel of the trolley close to the stairs, press down the handrail, and the front wheel will be lifted by the rubber band, and then push the trolley so that the front wheel can ride on the stairs above; Lift the armrest again, and the rear wheel is suspended. The rear wheel is pulled up by the rubber band and pushed forward slightly, so that the rear wheel can ride on the next stair? The car climbed upstairs step by step.

3, automatic pumping plug

Students who keep goldfish may know that when using siphon principle to change water in a fish tank, in order to eliminate the air in the pipeline, either fill the water in the water changing pipeline first, or suck one end of the water changing pipeline in your mouth. This is neither hygienic nor convenient.

Find a rubber plug (usually a rubber tube) about the same size as the inner diameter of the water exchange pipe. Tie a strong line through the center of the rubber plug and tie a small weight at the other end of the line.

Before changing water, put the small weight tied on the line at one end of the water exchange pipe and take it out from the other end. In this way, the wire passes through the water exchange pipe, and the rubber plug plugs one end of the water exchange pipe. When changing water, put the end with rubber plug into the bottom of the water. Pull the small weight by hand, pull out the rubber plug from the water exchange pipeline, and at the same time drive away the air in the pipeline, and the water will continue to flow out along the pipeline. If you use a water tank to hold water at home, you can also use this method to pump out the sediment at the bottom of the tank.