Who gave me some ideas for small inventions? I need someone to come right away.

1. We know that we usually find some old batteries in the drawer, but we don't know if there is electricity. If we put them in electrical appliances, it will be very troublesome and we can't know the remaining power. So, you can make a small electroscope.

The method is simple as follows: use small light bulbs, very small ones (such as pendants or toy lights, which are sold in hardware stores). Then connect the lamps with two thin enameled wires respectively. The other ends of the two wires are used to connect the positive and negative poles of the battery you want to test. According to the brightness of the small light bulb, the battery charge can be judged.

2. Take a broken umbrella, remove the cloth, take a wire, connect one end to the TV or radio, and the other end to the umbrella, which is a good signal receiver. If you want to be professional, put more threads around the umbrella. This is the cheapest and quickest way, but it's a bit funny.

Put a match and a sewn needle together, wrap them tightly with aluminum foil wrapped in cigarettes, then bend and seal the end of the aluminum foil with a matchstick and tighten it. Then install the directional tail near the tail and pull out the needle, which becomes a very simple recoil rocket.

In the experiment, a small rocket was placed on a wire rack, a match was lit, and the part of the aluminum foil tube covered with a matchstick was heated. When the temperature rises to the ignition point of the matchhead, the matchbox in the foil is ignited, which makes the surrounding air expand rapidly and the gas is ejected from the tail mouth at high speed. Due to the recoil, the rocket launcher flew forward from the frame.

If two matchsticks are put together face to face and wrapped in aluminum foil, both ends are not closed. Put it on the table and heat it from the middle. When the match in the cylinder is lit, the gas is ejected from both ends, and the aluminum foil cylinder remains on the frame, which shows the momentum conservation of the system.

4. Rivet two identical protractors at the center of the circle and rotate flexibly. Cut a notch with a length of 1 cm along the right end of the protractor above. When measuring the angle, make its opening coincide with both sides of the angle to be measured, and the scale indicated by the notch is the degree of the angle; When drawing a corner, first aim the notch at a specified proportion, and then draw two rays along the opening. This protractor can also measure the angle of solid objects (such as nuts).

Because this protractor works like scissors, we call it "scissors protractor".

five

I recommend my classmate's small production to you.

He made a small electronic balance model. Note that this model can only weigh very light objects, such as two small pieces of paper. The materials needed for production are: a wooden board (preferably thinner, not too big), a washer, a paper clip, an awl, an electric soldering iron, several wires, two light-emitting diodes and a battery. These materials are easy to find. If there is no led, you can go to the electronic market to buy it. They are very cheap.

The manufacturing process is as follows: drill a small hole in the middle of the board with an awl, bend a paper clip into a hook shape and fix it on the board through the small hole perpendicular to the board, as long as the washer can be hung on the hook. Then take two paper clips and straighten them in half, leaving only one corner. In fact, the straight part is the arm of the balance, and the remaining curved part is the tray. Another paper clip does the same thing. Then use the middle washer to weld the two paper clips together, and the paper clips should be in a straight line. Then hang the washer on the hook, adjust the distance between the hook and the board, about 3 mm, then fix two paper clips under the two trays, and prepare led as the indicator light next to the paper clips. A circuit is arranged under the board, and the balance is equivalent to a single-pole double-throw switch. This circuit is equivalent to two loops, using a power supply and two light emitting diodes. As long as the left side sinks, the tray on the left side will be connected with the pin below him, so that the circuit will be connected and the diode will emit light; If the two sides are equal in weight, the circuit is blocked and both diodes are not lit.

Add some hope you can be satisfied!

Finally, I wish you a smooth production and a happy mood!

First, the small balance

Tips: It must be done with the help of parents!

1. First cut the plywood into four pieces: A, B, C and D.

2. The bottom opening of B is the middle opening of C and D..

3. Insert three thin strips as shown in the figure.

4. Nail A to the middle and upper section of B, but be careful not to nail it to death, and be able to move freely.

5. Cut the crescent-shaped target board with plywood and mark it with scales.

6. Cut a small piece and fix it on A with all-purpose glue, as shown in the figure.

7. Cut two disks of equal size.

8. Make four holes at the top.

9. cut a small ditch on each side of a.

10. Tie the chip with a thin thread, and the balance will be done.

Next, you can use your imagination to decorate the small balance and use it as a gadget after the experiment. This is killing two birds with one stone.

Second, the actor walks a tightrope.

Actors always carry a long stick when walking a tightrope. Maybe everyone will think, isn't this an increase in the burden on actors? When you finish the following experiment, you will change this view.

I. Materials

A blank board, a 10 cm-long iron wire, a thumbtack, a lump of plasticine, a 30 cm-long and 2 cm-wide thin iron sheet, adhesive tape, glue, scissors, ruler, etc.

Second, production.

1. Cut it into the shape of a villain with cardboard, draw the five senses, color it, and stick a support bar behind it. The villain's feet are folded forward and the support rod is folded back. Stick a thumbtack with glue, cut off the extra part, and fold back the thumbtack tip.

2. Straighten the wire, pinch two balls of the same size with plasticine, fix them at both ends of the wire, and then stick the middle of the wire on the villain's "hand" with tape, so that the villain can stand.

3. Touch the center paper of the iron sheet vertically with a ruler, fold the iron sheet into a right angle, put it on the table with the angle down, then fix it with adhesive tape, put the upright villain, align the nail hook with the groove, and let the villain slide down slowly from the upper end to keep it smooth.

Third, reveal secrets.

Objects are attracted by the earth, and the balance of objects depends on the position of their center of gravity. The lower the center of gravity, the more stable the object is. A long and drooping stick can lower the center of gravity, and the increase of weight is also beneficial to balance. Therefore, an actor walks a tightrope with a stick.

Third, make a hot air balloon (Kongming Lantern)

Let's make a hot air balloon together. The hot air from the hair dryer can make it rise slowly, just like a real hot air balloon.

1. First, we cut 6-8 leaflike pieces of paper from soft paper.

2. Fold them in half and stick the edges together to make a balloon.

3. Stick the four connecting wires to the bottom of the balloon with adhesive tape. Fix the other end of the line on the table with plasticine.

Try to set the speed of the hair dryer very slowly. Aim the air outlet upward at the opening at the bottom, and then turn on the switch. The balloon will gradually get bigger, tighten the line and leave the table.

You can be a turtle sweeping the floor. You have a shoe brush. Grind off the handle of the shoe brush, press the motor on it, then stick a cake plate on it, do some decoration, start the motor, and the little turtle will leave!

Prepare materials and tools for making sand table: chassis, track, pigment, grass powder, turf, silicone gun, waste newspaper, white glue, gypsum, etc.

According to the need, you can design the shape and height of the track yourself and add it with hot silica gel. (Note: it must be firmly bonded, and there can be no looseness or inclination. )

Stick masking paper on the track to prevent impurities from entering in the production process and should not be removed. Molded into a pre-designed shape with waste newspapers, it can be fixed with masking paper, then covered with plaster bandage and sprayed with water.

After the basic shape is fixed, pouring gypsum will make the whole shape more three-dimensional and easy to color. (Note: avoid the track when pouring gypsum)

Glue the building to the already made shape.

Color, color is to pay attention to draw dark color first, then draw medium color, and finally draw highlights, weathering effect, and then plant vegetation.

Plant vegetation and sprinkle grass powder, and the simple sand table will be basically ready. Finally, don't forget to hit the track with sharpie, and it's over.

Make a Kongming Lantern!

It can fly by itself!

2. 1 materials and production

① Take a large and thin plastic handbag and cut it flat in the portable part.

(2) Take a thin copper wire with a length of about 60cm (one of many soft copper wires can be used), and tie both ends to both sides of the opening of the convenient bag.

③ A simple Kongming lantern was made by wrapping a proper amount of cotton in the middle of a thin copper wire. As shown in the figure.

2.2 release

Choose a place where there is no wind (or indoors). One person holds the two corners at the bottom of the convenient bag with both hands, so that the opening is downward, and the thin copper wire wrapped in cotton naturally hangs down. Pour a proper amount of alcohol on cotton and light the alcohol. In a few tens of seconds, Kongming Lantern will fly.

2.3 attention

① Alcohol cotton should not be overweight. Generally, it can make the total mass (the total mass of convenient bag, fine copper wire and alcohol cotton) easier to take off below 5g.

(2) The length of thin copper wire should be appropriate to avoid dissolving plastic bags after alcohol combustion, and pay attention to fire prevention.

(3) If you want to pull it down, you can tie a thin copper wire in the middle of the thin copper wire in advance to make it droop.

Actors always carry a long stick when walking a tightrope. Maybe everyone will think, isn't this an increase in the burden on actors? When you finish the following experiment, you will change this view.

I. Materials

A blank board, a 10 cm-long iron wire, a thumbtack, a lump of plasticine, a 30 cm-long and 2 cm-wide thin iron sheet, adhesive tape, glue, scissors, ruler, etc.

Second, production.

1. Cut it into the shape of a villain with cardboard, draw the five senses, color it, and stick a support bar behind it. The villain's feet are folded forward and the support rod is folded back. Stick a thumbtack with glue, cut off the extra part, and fold back the thumbtack tip.

2. Straighten the wire, pinch two balls of the same size with plasticine, fix them at both ends of the wire, and then stick the middle of the wire on the villain's "hand" with tape, so that the villain can stand.

3. Touch the center paper of the iron sheet vertically with a ruler, fold the iron sheet into a right angle, put it on the table with the angle down, then fix it with adhesive tape, put the upright villain, align the nail hook with the groove, and let the villain slide down slowly from the upper end to keep it smooth.

Third, reveal secrets.

Objects are attracted by the earth, and the balance of objects depends on the position of their center of gravity. The lower the center of gravity, the more stable the object is. A long and drooping stick can lower the center of gravity, and the increase of weight is also beneficial to balance. Therefore, an actor walks a tightrope with a stick.

Making pinhole camera

Method:

Pinhole camera

According to the principle of pinhole imaging, a pinhole imager can be made and a clear image can be seen on its screen. If you put a photosensitive film on the screen, you can take a clear picture and become a pinhole camera. However, this requires a "shutter" and a slot for loading negatives. In addition, the requirements for sealing are stricter than those for making ordinary pinhole imagers.

The structure of pinhole camera is shown in Figure10.6-L. The camera body is made of toilet paper and is divided into two parts: the front cover and the back cover.

manufacturing method

Draw it on the toilet paper according to the size of figures 10.6-2, 10.6-3, 10.6-4 (δ is the thickness of toilet paper), cut it along the solid line of each figure, and then gently carve it with a knife along the dotted line. Don't cut it, so as to fold the straight edge when bending. Then paint both sides of each block black.

Bend the cut front cover outer layer development drawing (Figure 10.6-2) by 90 degrees along the dotted line to form a five-sided paper box, and stick it with adhesive tape. Then stick a piece of 120 film black lining paper on one side with a round hole, and tie a small hole with a diameter of about 0.4 mm on the lining paper in the center of the round hole with a needle (the diameter of 12 sewing needle is about 0.4 mm). Then, as shown in figure 10.6- 1, stick a paper slot on the edge of the small hole and insert a hard paper strip in the paper slot, which can be used as a blind and keep the small hole clean.

Bend the cutting development diagram of the inner layer of the front cover (Figure 10.6-3) by 90 degrees along the dotted line, make it into a square cylinder, and attach the joint (the tongue is attached to the inside of the square cylinder). Then, fold the trapezoidal tongue at the notch end into a paper frame, align the notch with the reinforcing frame (Figure 10.6-4) and stick them together. Cut a paper frame with cardboard according to the size of the reinforced frame, align the gap and stick it on the reinforced frame, and stick this paper frame with the square tube outside with adhesive tape, so that a paper slot is formed between the reinforced frame and the rigid paper frame, and the negative can be loaded or taken out from the notched side. This gap is designed to facilitate the loading and unloading of negatives. After the inner layer is finished, the outer layer should be glued, that is, each trapezoid uvula at the other end of the square tube should be bent 90 degrees along the dotted line, coated with glue, aligned with the gap, and inserted into the outer layer. At the same time, a piece of toilet paper should be inserted between the inner layer and the outer layer of each face to ensure the same gap between the inner layer and the outer layer. After the front end of the inner layer is stuck to the surface with a round hole in the outer layer, the inserted toilet paper is pulled out, and the front cover is completed.

As for the manufacture of the back cover, except that the side width is 80+26 mm and there is no hole in the bottom surface, everything else is the same as the outer layer of the front cover. You can refer to the development diagram and corresponding dimensions of the outer layer of the front cover to make it.

Application mode

1. The pinhole camera has a fixed image distance of about 64 mm and a fixed aperture of 0.4 mm, so the aperture is also fixed. Experiments show that the pore size is about 160. When the brightness of the subject is different, it can only be adjusted by exposure time. Because the aperture number of a general camera is about 22, it is impossible to find out the exposure time of aperture 160, so it can be determined according to the ratio of exposure time equal to the square of aperture ratio (that is, t 1: t2 = (f 1: f2) 2). For example, when shooting a scene, the exposure time of aperture 16 is 1/30 seconds, then the exposure time of pinhole camera aperture 160 should be 3.3 seconds. The best exposure time should also be determined by experiments.

2. When taking photos with a pinhole camera, the framing method is shown in Figure 10.6-5. Stick one eye at the midpoint of one side and look out at the opposite ends. Then, the part sandwiched at this angle is the range to be taken. Moving the distance between the camera and the scene can change the image size.

3. Exposure: Take a good picture, calculate the exposure time, open the cardboard covering the small hole and close it until the scheduled exposure time.

4. Film loading and unloading: a single 60×60 mm 2 film is often difficult to buy, so it needs to be cut with a large film. Film loading, unloading and film cutting should be carried out in a dark room without light.

Matters needing attention

1. Be careful not to leak light when making.

2. Pinholes should be round and smooth.

3. Due to the long exposure time, it is advisable to shoot still life.

Shoe mop-a portable and non-bending mopping tool.

Production method: 1, the shoe mop is bigger than the shoes you usually wear, so it is convenient to put on your shoes.

2. Use rag strips as mop strips of soles, and nail thick plastic soles on the mop strips, which is waterproof and durable.

3. The upper is made of cloth shell and waterproof cloth, and the back root of the upper has a zipper, which is convenient to put on and take off. Connect the upper with the sole, and the shoe mop will be finished.