The power of chopsticks
Thinking: Insert a chopstick into a cup filled with rice, and then lift the chopstick. Can chopsticks lift rice and cups?
Materials: a plastic cup, a rice cup and a bamboo chopstick.
Operation:
1. Fill the plastic cup with rice.
2. Press the rice in the cup by hand.
3. Hold the rice with your hands and put chopsticks between your fingers.
4. Gently lift chopsticks with your hands, and the cup and rice are lifted together.
Explanation:
Because of the extrusion between rice grains in the cup, the air in the cup is squeezed out, and the pressure outside the cup is greater than that inside the cup, so that chopsticks and rice grains are tightly combined and chopsticks can hold the rice cup.
Bottle race
Thinking: Two bottles of the same weight, one filled with sand and the other filled with water, roll down from a height. Who will reach the finish line first?
Materials: two bottles of the same size and weight, sand, water, a rectangular board and two thick books.
Operation:
1. Make a slope with a rectangular board and two books.
2. Pour water into another bottle and sand into the bottle.
3. Put two bottles on the board and let them roll down at the same starting height at the same time.
The bottle filled with water reaches the finish line earlier than the bottle filled with sand.
Explanation:
The friction between sand and the inner wall of the bottle is much greater than that of water, and there will be friction between sand, so its sliding speed is slower than that of a bottle filled with water.
Creation: change the substances in the bottle and let them compete!
Paid newspaper
Thinking: Without glue, tape and other things, newspapers can stick to the wall without falling off. Do you know why?
Material: 1 pencil; 1 newspaper.
Steps:
1. Spread the newspaper and lay it flat on the wall.
2. After a few quick rubs on the newspaper with one side of the pencil, the newspaper won't fall off just like sticking to the wall.
3. Lift a corner of the newspaper, and then let go, and the lifted corner will be sucked back by the wall.
Take the newspaper off the wall slowly and pay attention to the static sound.
Description:
1. Wipe the pencil to charge the newspaper.
2. The charged newspaper was sucked to the wall.
When the indoor air is dry (especially in winter), if you take down the newspaper from the wall, you will hear the crackle of static electricity.
Creation: Please have a try. What else can be stuck to the wall by static electricity without glue?
Separation of pepper and salt
Thinking: I accidentally mixed the kitchen condiments: pepper and salt. How can I separate them?
Ingredients: pepper, salt, plastic spoon, small dish.
Operation:
1. Mix salt and pepper.
2. Stir well with chopsticks.
3. Rub the plastic spoon on the clothes and put it on the salt and pepper.
4. Pepper sticks to the spoon first.
5. Move the plastic spoon down slightly.
6. After salt, stick it on the spoon.
Explanation:
Pepper is electrostatically adsorbed earlier than salt because its weight is lighter than salt.
Create:
Can you separate other mixed materials in this way?
Inflatable balloon
Thinking: When will two balloons attract each other and repel each other?
Material: 2 inflatable balloons, 1 string, 1 cardboard.
Operation:
1 Inflate two balloons separately and tie a knot in your mouth.
Connect two balloons with a thread.
Rub the balloon on your hair (or sweater).
Lift the middle part of the rope and the two balloons will separate immediately.
Put the cardboard between two balloons, and the electricity on the balloons makes them attracted to the cardboard.
Explanation:
The electricity on one balloon repels the electricity on the other balloon.
The electricity on the two balloons attracts them to the cardboard.
Creation: Can other small experiments be used to illustrate that balloons are charged?
Lovely watermark
Thinking: The beautiful patterns on rice paper are not drawn, but how are they made?
Materials: 1 washbasin, 1-2 rice paper, 1 chopsticks, 1 cotton swab, 1 bottle of ink and water (about half a basin).
Operation:
1. Pour half a basin of water into the washbasin and gently touch the water surface with chopsticks dipped in ink to see the ink on the water surface.
Expand into a circle.
2. Wipe the scalp with a cotton swab for two or three times.
3. Then touch the center of the ink circle and see what happens.
4. Gently cover the calligraphy paper on the water, and then pick it up slowly. What patterns are printed on the paper?
Explanation:
1. When the cotton swab touches, the ink will swell into an irregular circular pattern.
2. A small amount of oil on the scalp rubbed by cotton swabs will affect the mutual pulling force of water molecules.
3. The watermark will present irregular concentric circles.
Create:
Try other methods to change the ink pattern on the water surface.