Electric newspapers
Thinking: Without glue, tape and other adhesives, newspapers can be stuck on the wall without falling off. Do you know why?
Materials: 1 pencil; 1 newspaper.
Steps:
1. Unfold the newspaper and lay it flat on the wall.
2. After quickly rubbing the side of the pencil on the newspaper a few times, the newspaper will not fall off as if it is stuck to the wall.
3. Lift up a corner of the newspaper and then let go. The lifted corner will be sucked back by the wall.
4. Slowly peel the newspaper off the wall and listen for the sound of static electricity.
Instructions:
1. Rub the pencil to electrify the newspaper.
2. The charged newspaper was sucked to the wall.
3. When the air in a house is dry (especially in the winter), if you peel the newspaper off the wall, you will hear a static crackling sound.
Creation: Please try it, what other items can be stuck on the wall using static electricity without using adhesives
Separation of pepper and salt
Thinking: I accidentally mixed the kitchen condiments: pepper and salt together. How to separate them?
Materials: pepper, salt, plastic spoon, small plate
Operation:
1. Mix salt and pepper together.
2. Stir evenly with chopsticks.
3. Rub the plastic spoon on the clothes and place it on top of the salt and pepper.
4. The pepper adheres to the spoon first.
5. Move the plastic spoon downward slightly.
6. The salt sticks to the spoon.
Explanation:
The reason why pepper is electrostatically adsorbed earlier than salt is because its weight is lighter than salt.
Create:
Can you use this method to separate other mixed ingredients?
Electric Balloons
Thinking: Under what circumstances will two balloons attract each other, and under what circumstances will they repel each other?
Materials: Inflated Balloons 2 , 1 piece of string, 1 piece of cardboard
Operation:
1 Inflate the two balloons separately and tie a knot at the mouth.
2 Connect the two balloons with string.
3 Rub the balloon on your hair (or sweater).
4 Lift the middle part of the string and the two balloons immediately separate.
5 Place cardboard between two balloons and the electricity on the balloons causes them to be attracted to the cardboard.
Explanation:
1 The electricity on one balloon repels the electricity on the other balloon.
2 The electricity on the two balloons causes them to be attracted to the cardboard.
Create: Can you use other small experiments to show that the balloon is charged?
Cute watermark
Thinking: How are the beautiful patterns on rice paper made if they are not drawn?
Materials: 1 washbasin, 1-2 pieces of rice paper, 1 chopstick, 1 cotton swab, 1 bottle of ink, water (about half a basin)
Operation:
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1. Pour half a basin of water into the basin and gently touch the water surface with chopsticks dipped in ink. You will see the ink expand into a circle on the water surface.
2. Take a cotton swab and rub it on the scalp two or three times.
3. Then tap the center of the ink circular pattern to see what happens.
4. Gently cover the calligraphy paper on the water, and then slowly pick it up. What pattern is printed on the paper?
Explanation:
1. When the cotton swab is touched, the ink will expand into an irregular circle shape.
2. The small amount of oil applied when the cotton swab is rubbed on the scalp will affect the force of water molecules pulling each other.
3. The watermark will appear in irregular concentric circles.
Create:
Try other ways to change the shape of the ink on the water.
The splitting and merging of water flows
Thinking: Why do multiple streams of water turn into one stream of water when you touch it with your hands?
Materials: One tin can box, awl, water
Operation:
1. Use a nail to drill 5 holes in the bottom of the empty tin can box. small holes (the distance between the small holes is only about 5 mm).
2. Fill the tank with water. The water will be divided into 5 streams and flow out from the 5 small holes.
3. Use your thumb and index finger to twist the water flows together.
4. After taking your hand away, 5 strands of water will merge into one strand.
5. If you wipe the small hole on the can with your hand, the water will turn into 5 strands again.
Explanation:
The surface tension of water causes the water flow to divide and merge.
Floating needle
Thinking: Why does the needle float on the water?
Materials: a bowl of water, needle, fork, liquid detergent
Operation:
1. Pour a cup of water into the cup
2. Use a fork to carefully place a needle on the surface of the water
3. Slowly remove the fork and the needle will float on the water
4. Towards Drop a drop of detergent into the water and the needle will sink
Explanation:
1. It is the surface tension of the water that supports the needle and prevents it from sinking. Surface tension is the cohesive bonds formed by water molecules. This cohesive connection is due to a certain part of the molecules being attracted together and squeezing each other to form a thin film. This thin film is called surface tension, and it holds up objects that would otherwise sink.
2. The detergent reduces the surface tension and the needle cannot float.
Note: Needles are dangerous, parents are asked to help operate them.
Magic Toothpick
Thinking: Will a toothpick placed in water swim with the sugar cubes placed in the water, or with the soap placed in the water? ?
Materials: toothpicks, a basin of water, soap, sugar cubes
Operation:
1. Place the toothpick carefully on the water.
2. Put the sugar cube into the water basin far away from the toothpick. The toothpick will move towards the sugar cube.
3. Change a basin of water, carefully place the toothpick on the water, and now put the soap in the basin closer to the toothpick. The toothpick will stay away from the soap.
Explanation:
When you put the sugar cube into the center of the water basin, the sugar cube will absorb some water, so a small amount of water will flow in the direction of the sugar cube. The toothpick also moves with the water flow. However, when you put the soap into the basin, the surface tension on the edge of the basin is stronger, so the toothpick will be pulled outward.
Creation: Please try to see which direction the toothpick will swim if you replace sugar and soap with other substances
Perforated paper to hold water
Thinking: Why can paper with holes hold water?
Materials: A bottle, a pin, a piece of paper, and a full cup of colored water
Operation:
p>1. Fill the empty bottle with colored water.
2. Poke many holes in the white paper with a pin.
3. Cover the mouth of the bottle with the perforated paper.
4. Press the paper with your hand and turn the bottle upside down so that the bottle mouth faces down.
5. Gently remove your hand, the paper does not cover the mouth of the bottle, and the water does not flow out of the hole.
Explanation:
The thin paper can hold up the water in the bottle because the atmospheric pressure acts on the paper, creating an upward force. Small holes will not leak water because water has surface tension, and water forms a thin film on the surface of the paper, preventing water from leaking out. This is like an umbrella made of cloth. Although the cloth has many small holes, it still does not leak.
The secret of the handkerchief
Thinking: Spread the handkerchief flat under the faucet, turn on the faucet, will the water flow down through the handkerchief?
Materials: 1 glass, 1 handkerchief, 1 rubber band
Process:
1. Cover the mouth of the cup with a handkerchief and a rubber band Tie tight.
2. Let the water wash on the handkerchief.
3. Turn off the faucet after the water flows into the cup until it is about 70-80% full.
4. With the mouth of the cup facing down, quickly turn the cup over.
Instructions:
1. When flushing water from the cup, the water will flow into the cup through the handkerchief.
2. When the cup is turned upside down, the water will not flow out due to atmospheric pressure.
Extension:
If the cloth covering the mouth of the cup is different (such as cotton cloth, towel, linen), what will happen to the ingress and egress of water?
A plastic backing plate that cannot fall off
Thinking: If a cup filled with water is covered with a backing plate, will the backing plate fall off when the cup mouth is facing down?
Materials: two glasses, water, one plastic plate
Operation:
1. Fill the glass with water.
2. Cover the mouth of the cup with a backing plate.
3. Hold the cup with one hand and press the backing plate with the other hand.
4. Hold it with your hands and turn the cup over so that the cup is facing down.
5. Gently release the hand holding the pad so that the pad will not fall down.
Explanation:
The backing plate covers the mouth of the cup containing water. Because the air pressure outside the cup is relatively high, the backing plate will not fall off.
Creation:
What will happen if the water in the cup is not full, or there is no water on the plastic plate? Please give it a try?
The candle cannot be blown out
p>Thinking: Blow the burning candle hard, but you can't blow it out. Do you know how to do this?
Materials: 1 candle, match, 1 small funnel, 1 flat plate
Operation:
1. Light the candle and fix it on the flat plate superior.
2. Make the wide mouth of the funnel face the flame of the candle, and blow forcefully from the small mouth of the funnel into the flame.
3. Make the small mouth of the funnel face the flame of the candle, and blow forcefully from the wide mouth of the funnel towards the flame.
Explanation:
1. When blowing in this way, the flame will be inclined toward the wide end of the funnel and will not be easily blown out. The candle will be easily extinguished if air is blown from the wide end of the funnel.
2. When the blown gas changes from a narrow mouth to a wide mouth, it gradually evacuates and the air pressure weakens. At this time, the gas around the wide mouth of the funnel will flow into the wide mouth of the funnel due to the strong air pressure. Therefore, the flame of the candle will also rush towards the wide mouth of the funnel.
Note: Pay attention to safety when burning candles.
Candle pump
Thinking: Do you know how a water pump pumps out water?
Materials: glass, candle, cardboard slightly larger than the mouth of the glass, plastic tube, a little Vaseline, matches, half a cup of water
Operation:
1. First fold the plastic tube into a door frame shape and pass one end through the cardboard
2. Then place the two glasses on the table, one on the left and one on the right
3. Light the candle and fix it at the bottom of the left glass, and pour water into the right glass at the same time
4. Apply some Vaseline to the mouth of the cup where the candle is placed, and then cover it with a piece of cardboard threaded with a plastic tube and submerge the other end of the plastic tube into the water in the cup on the right.
5. Water flows from the right into the cup on the left
Explanation: The burning of the candle uses up the oxygen in the cup on the left, the air pressure in the bottle decreases, and the pressure in the cup on the right causes the water to flow into the cup on the left Flow until the pressure on the water in the two cups is equal. At that time, the water surface of the left cup is higher than the water surface of the right cup.
Note: Pay attention to safety when lighting the candle and fixing it at the bottom of the glass on the left, be careful not to burn your hands
Blowing up the balloon inside the bottle
Thinking: Blowing up the balloon inside the bottle Balloon, why doesn't the balloon become smaller when you release the mouth of the balloon?
Materials: wide-mouth glass bottle, two straws: red and green, one balloon, air pump
Operation:
1. Use a screwdriver to put on the bottle cap in advance Punch two holes and insert two straws into the holes: red and green
2. Tie a balloon on the red straw
3. Put the bottle cap on the bottle. on the mouth
4. Use an air pump to hit the red straw to make the balloon bigger
5. Release the red straw and the balloon will immediately become smaller
6. Use an air pump to make the balloon bigger.
Use the red straw to make the balloon bigger
7. Quickly pinch the red straw and the green straw tightly
8. Release the red straw and the balloon will not become smaller
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Explanation: When the red straw is released, the balloon begins to shrink because the rubber membrane of the balloon shrinks. However, after the volume of the balloon shrinks, the volume of the air in other parts of the bottle expands, and the green tube is closed. As a result, the air pressure in the bottle will decrease—even lower than the pressure in the balloon. At this time, the balloon will no longer shrink. .
A cup that can catch balloons
Thinking: Would you use a small cup to gently place it upside down on the surface of the balloon, and then suck up the balloon?
Materials: 1 to 2 balloons, 1 to 2 plastic cups, 1 thermos bottle, a little hot water
Process:
1. Blow up the balloons Inflate and tie up
2. Pour hot water (about 70℃) into the cup for about half a cup
3. After the hot water stays in the cup for 20 seconds, pour the water Come out
4. Immediately place the rim of the cup upside down tightly on the balloon
5. Gently lift the cup together with the balloon
Instructions:
1. If the cup is directly placed upside down on the balloon, the balloon cannot be sucked up.
2. Cups treated with hot water can suck up balloons because the air in the cup gradually cools down and the pressure becomes smaller.
Extension:
Children, please think of any other ways to suck up balloons?
A cup that absorbs water
Thinking: Use a glass cup to cover a burning candle. What happens inside the cup after the candle goes out?
Materials: 1 glass (taller than the candle), 1 candle, 1 flat plate, 1 lighter, some water
Operation:
1. Light the candle and put a few drops of wax in the center of the plate to secure the candle.
2. Pour about 1 cm of water into the plate.
3. Place the glass upside down on the candle
4. Observe the burning of the candle and the changes in the water level in the plate
Explanation:
1. After the air (oxygen) in the glass is consumed, the candle goes out.
2. After the candle goes out, the water level in the cup will gradually rise.
Create:
Can you use an empty container to automatically collect other solutions?
A bottle that can eat eggs
Thinking: Why can eggs go in from the mouth of a bottle smaller than myself?
Materials: 1 cooked egg, 1 narrow-mouth bottle, some pieces of paper, 1 box of matches
Operation:
1. Peel off the cooked eggs shell.
2. Tear the paper into long strips.
3. Light the note and put it into the bottle.
4. As soon as the fire goes out, snap the egg onto the mouth of the bottle and remove your hand immediately.
Explanation:
1. When the paper is just burned, the bottle is hot.
2. After the egg is fastened to the mouth of the bottle, the temperature inside the bottle gradually decreases, and the pressure inside the bottle becomes smaller. If the pressure outside the bottle becomes greater, the egg will be squeezed into the bottle.
Creation: What happens to the bottle when the pressure of the gas in the bottle is greater than the pressure outside the bottle?
A deflated bottle
Think: Can you deflate a plastic bottle without using your hands?
Materials: 2 water cups, 1 cup of warm water, 1 mineral water bottle
Operation:
1. Pour warm water into the bottle and touch it with your hands Touch the bottle to see if it feels hot.
2. Pour the warm water out of the bottle and quickly close the cap tightly.
3. Observe that the bottle slowly deflates.
Explanation:
1. Heat the air in the bottle to reduce its pressure.
2. Because the air outside the bottle has a greater pressure than the air inside the bottle, the bottle is crushed.
Create:
If the pressure of the gas in the bottle is greater than the pressure of the air outside the bottle, what will the bottle look like?
A ping-pong ball that can jump long
Thinking: If a ping-pong ball is placed in a goblet, how do you blow to make the ball jump out of the cup?
Materials: 2 goblets, 1 table tennis ball
Operation:
1 Place two goblets side by side
2 Place the ping pong ball in the first cup.
3. Blow from different angles to see what happens to the table tennis ball: blow towards the side of the ball; blow towards the top of the ball
Explanation:
1. Blow to the side of the ball so that the table tennis ball will not easily jump into the second cup (or jump out)
2. Blow to the top of the ball and the pressure above will become smaller. The ping pong ball will float, continue to blow, and jump into the second cup
Creation: Use a new method to make the ping pong ball jump into the next cup
Can blow Bottle with bubbles
Thinking: Do you know how a bottle blows bubbles?
Materials: 1 beverage bottle, 1 cup of hot and cold water, 1 cup of colored water, 1 large plate, 1 piece of plasticine, some straws
Operation:
1 Connect the straws one by one to form a long tube (the connections are sealed with tape).
2 Put the straw into the bottle, seal the mouth of the bottle with plasticine, and then place the bottle on the plate.
3 Bend the straw so that the other end of the straw goes into the glass of colored water.
4 Pour hot water on the wall of the bottle, and the straw in the cup will release a lot of bubbles.
5 Pour cold water on the sides of the bottle.
6 The water in the glass will flow into the bottle through the straw.
Explanation:
1 Because the plastic bottle is very thin, heat can pass through the bottle wall and enter the air in the bottle.
2 The air in the bottle expands when heated.
3 The bubbles in the water are the air that is squeezed out of the bottle when the air expands.
4 The air in the bottle shrinks when it is cold.
5 As the air in the bottle contracts, water takes up the remaining space.
Creation: When the bottle cap is too tight, do you know the best way to open it