Magic toothpick
Thinking: Will the toothpick in the water swim with the sugar cubes in the water or with the soap in the water?
Ingredients: toothpick, a basin of water, soap, sugar cube.
Operation:
1. Carefully put the toothpick on the water.
2. Put the sugar cubes in the basin, away from the toothpicks. The toothpick will move towards the sugar cube.
Change a basin of water, carefully put the toothpick on the water, and now put the soap in the basin near the toothpick.
Toothpicks will stay away from soap.
Explanation:
When you put the cube in the center of the basin, it will absorb some water, so there will be a small water flow in the direction of the cube, and the toothpick will move with the water flow. However, when you put soap into the basin, the surface tension at the edge of the basin is strong, so you will pull the toothpick out.
Creation: Please try. If sugar and soap were replaced by other substances, which direction would the toothpick swim?
Perforated paper can hold water.
Thinking: Why can perforated paper block water?
Material: a bottle, a pin, a piece of paper, a full cup of colored water.
Operation:
1. Fill the empty bottle with colored water.
Punch many holes in the white paper with a pin.
3. Cover the bottle mouth with perforated paper.
4. Hold the paper with your hand, turn the bottle upside down, and make the bottle mouth face down.
Gently remove your hand, the paper will cover the bottle mouth and the water will not flow out of the hole.
Explanation:
A thin piece of paper can hold up the water in the bottle, because atmospheric pressure acts on the paper, producing upward tension. Water will not leak out from the small holes because water has surface tension, and water forms a water film on the surface of paper, so water will not leak out. This is like an umbrella made of cloth. Although this cloth has many holes, it still won't leak rain.
The secret of handkerchief
Thinking: Lay the handkerchief flat under the faucet and turn on the faucet. Does water flow through the handkerchief?
Material: 1 glasses, 1 handkerchief, 1 rubber band.
Process:
1. Cover the cup with a handkerchief and tie it with a rubber band.
2, 2, let the water rush on the handkerchief.
3.3. Turn off the tap after the water flows into the cup for about seven or eight minutes.
4, 4, cup mouth down, quickly turn the cup upside down.
5. Description:
6. 1 When flushing from the top of the cup, water will flow into the cup through the handkerchief.
7.2. When the cup is turned upside down, water will not flow out due to atmospheric pressure.
8. Expand:
9. If the cloth covering the handkerchief is different (such as cotton cloth or towel or linen), what will happen to the incoming and outgoing water?
Plastic backing plate that won't fall off.
Thinking: Cover a cup full of water with a pad. Will the backing plate fall off when the cup mouth is facing down?
Materials: two glasses, water and a plastic plate.
Operation:
1. Fill the glass with water.
2. Cover the cup with a pad.
Hold the cup in one hand and the mat in the other.
4. Hold it by hand, turn the cup mouth upside down, and let the cup mouth face down.
Let go of the hand holding the pad gently, and the pad won't fall off.
Explanation:
The cushion is covered on the mouth of the cup containing water, because the air pressure outside the cup is relatively high, and the cushion will not fall off.
Create:
There is not enough water in the cup, or what if there is no plastic plate? Please try it.
The candle won't go out.
Thinking: Blow out the burning candle hard, but it won't go out. Do you know how to do it?
Material: 1 candle, match, 1 small funnel, 1 flat.
Operation:
1. Light the candle and fix it on the flat plate.
2. Let the wide mouth of the funnel face the flame of the candle, and blow the flame forcefully from the small mouth of the funnel.
3. Let the small mouth of the funnel face the flame of the candle, and blow the flame forcefully from the big mouth of the funnel.
Explanation:
1. When blowing in this way, the flame will deviate to the wide mouth end of the funnel and will not be easily blown out. If you blow from the wide mouth of the funnel, the candle will go out easily.
2. The blown gas gradually empties from the narrow mouth to the wide mouth, and the air pressure is weakened. At this time, the gas around the funnel wide mouth will flow into the funnel wide mouth because of the strong air pressure. Therefore, the flame of the candle will also rush to the wide mouth of the funnel.
Attention: Pay attention to the safety of candles when burning.
Candle pump
Thinking: Do you know how the pump pumps water out?
Materials: glass, candles, cardboard slightly larger than the glass mouth, plastic pipe, a little vaseline, matches and half a glass of water.
Operation:
1. First, fold the plastic pipe into the shape of a door frame and pass one end through the cardboard.
Put two more glasses on the table, one on the left and the other on the right.
3. Light the candle, then fix it at the bottom of the left glass, and inject water into the right glass at the same time.
4. Put some vaseline on the mouth of the cup where the candle is placed, and then cover it with a piece of cardboard with a plastic pipe, so that the other end of the plastic pipe sinks into the water in the cup on the right.
5. Water flows into the cup on the left from the right.
Description: When the candle burns, there is oxygen in the left cup, and the air pressure in the bottle decreases. The pressure in the right cup makes the water flow to the left cup until the pressure on the water surface of the two cups is equal. At that time, the water level in the left cup was higher than that in the right cup.
Note: Be careful not to burn your hands when you light the candle and fix it at the bottom of the left glass.
Blow a balloon in a bottle
Thinking: Why doesn't the balloon become smaller when it is blown in a bottle?
Materials: large glass bottle, two red and green straws, a balloon and a pump.
Operation:
1. Punch two holes in the bottle cap with a screwdriver in advance, and insert two straws in the holes: red and green.
Tie a balloon on the red straw.
3. Cover the bottle cap on the bottle mouth.
4. Hit the red straw with the air pump to make the balloon bigger.
5. Loosen the red straw and the balloon will become smaller immediately.
6. Use the air pump, and then click the red straw to expand the balloon.
7. Quickly pinch the two nozzles of the red straw and the green straw.
8, let go of the red straw mouth, the balloon has not become smaller.
Explanation: Loosen the red straw, and the balloon will begin to contract due to the contraction of its rubber film. However, after the balloon is deflated, the air volume in other parts of the bottle becomes larger and the green tube is closed. In this way, the air pressure in the bottle will be reduced-even lower than that in the balloon. At this time, the balloon will not continue to shrink.