If you want to do it immediately, you can say a scientific, advanced, and practical invention!

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In the sun, put the white paper under a magnifying glass (the principle of light).

Homemade flashlight.

The specific method of making it is to remove one end of the lid of a waste can (such as a Lulu beverage can) and knock the other end with a round hammer. Roll up two No. 1 batteries with thick corrugated cardboard, and put the batteries with the positive pole facing up and the negative electrode facing down into the Youze can.

Find a suitable plastic lid (such as a magic big roll lid that can be fastened to Lulu cans) and dig a small circular hole in the lid** in such a size that the bulb is plugged in tightly. Insert the base of the bulb into the small hole. Take a piece of wire hunt and peel off the wire skin at both ends, wrap one end around the lamp base, and pierce a small hole through the side of the plastic cover with the other end.

Place the plastic lid over the can. Check that the bulb and battery are not in close contact with the pants. At this point, the disposable flashlight is ready.

When using, use your thumb to press the wire from the side wall on the weld that is not painted from the can, the flashlight will glow, and the thumb will jump off the wire, and the flashlight will be extinguished, which is very convenient to use.

Homemade sun cooker.

Find a concave reflector bowl on a large flashlight, and use rigid styrofoam or wood to cut a cylinder about 4 cm long, with a diameter just enough to fit into the reflector. Drill a fine hole transversely at one end of the cylinder, insert a wire with a diameter equivalent to the diameter of the hole, and then fold the two ends of the exposed wire into 90°, leaving 5 cm each. Insert the cylinder into the hole in the reflector and insert the ends of the wire into a styrofoam or wooden baseplate.

Sharpen the two ends of a thin bamboo skewer, insert one end into the cylinder of the reflective bowl**, and insert a small piece of potato at the other end. Place the device in the sun so that the reflector is facing the sun, and then patiently adjust the length of the skewers so that the potatoes are in the right spotlight. It won't be long before the potatoes are roasted in the sunlight and give off their aroma.

Teach you to do only four things.

1.Screen: art plus handicraft: scissors, colored pencils, bamboo (bamboo strips are sufficient), scotch tape, utility knife, pencil, etc.

A: Cut the bamboo into two bamboo strips with the thickness of toothpicks, and then cut it off without 8cm, a total of 5, of course, if you want the screen to be large, you can increase the length and quantity of the bamboo strips.

B: Look for colorful cardboard such as wall calendars with landscape paintings, and of course you can also draw your own. A total of four rectangular strips of paper (drawing strips) cut into 7 cm long and 3 cm wide strips are required.

C: Splice four strips of painting with five bamboo strips, add a strip between the two bamboo strips, and use scotch tape to complete.

D: Fold the semi-finished product along the junction of the bamboo strip and the painting strip to make the screen like a folding fan, and then let him hold it for a few minutes, and then pull it open, then a three-dimensional screen is ready, and you can also write some famous sayings on it! Very nice crafts!

2.Simple wind turbines.

Physics plus art plus production: a can, a pair of scissors, a tinplate, a wooden strip, a four-wheel drive motor, a bottle of super glue, some colored LED bulbs (or bulbs, diodes).

A: Use scissors to cut off the upper part of the can by about 1cm, keep the remaining can, that is, make a "cup" first, and then draw three at equal intervals on the cup, then keep these three, cut off the remaining excess, and then present a round base with three blades, like a propeller, and then use the tip of scissors to drill a round hole slightly smaller than the central axis of the motor in the middle of the base.