Make small inventions in grade four, and the related contents are as follows:

1. Make badminton by yourself

Preparation materials: an empty beverage bottle, two foam fruit nets, a rubber band and a glass marble.

manufacturing process: take an empty 25ml beverage bottle and cut off the top half of the bottle; Divide the cut part into 8 parts, cut it to the bottleneck with scissors, and then cut each part into petal shapes with the same size; Cover the foam fruit net outside the bottle and fix it at the mouth of the bottle with a rubber band.

wrap another foam fruit net around a glass marble, put it into the bottle mouth, and plug it tightly to expose about 1 cm; Cut off half a ping-pong ball, cover the bottom of the hemisphere on the bottle mouth, cut the four sides into whiskers, cover the bottle mouth and fix it with a rubber band. After beautification, a homemade badminton was finished. Hit a dozen with a badminton racket and see how it works.

2. Self-made soap paper

Materials and tools: white paper with good hygroscopicity, small pieces of soap, a brush and disposable beverage cans.

production method: firstly, chop up the soap and put it in a jar, then put the cup on the stove to heat it. When the soap melts, cut the white paper into matchbox sizes, coat it with soap solution one by one, and then take it out and dry it in the shade to get the soap paper.

3. Self-made hot air balloon

First, we cut out 6-8 leaflike pieces of paper from soft paper. Fold them in half and glue their edges together to make a balloon. Tape the four wires to the bottom of the balloon. Fix the other end of the line on the table with plasticine.

try to slow down the speed of the hair dryer. Aim the air outlet upward at the opening at the bottom and turn on the switch. The balloon will gradually get bigger, tighten the thread and leave the desktop.

4. Self-made flashlight

The specific manufacturing method is: lift one end of a waste pop-top can (such as Lulu beverage can), and knock the other end with a round-headed hammer. Roll up two No.1 batteries with thick corrugated cardboard, and put them into the can with the positive electrode facing up and the negative electrode facing down.

find a suitable plastic lid, such as a magic big-rolled lid, which can just be buckled on Lulu's beverage can, and dig a small round hole in the center of the lid, the size of which is suitable for the light bulb to be inserted tightly. Insert the bulb base into the small hole.

take a section of wire-finding, peel off the wire skin at both ends, wrap one end around the lamp holder, and pierce a small hole at the other end from the side of the plastic cover. Put the plastic lid on the can. Check whether the light bulb and battery are in close contact.

the disposable flashlight is ready here. When in use, the thumb is used to press the wire from the side wall on the unpainted weld from the can, and the flashlight will glow, and the thumb will jump off the wire and the flashlight will go out, which is very convenient to use.