A small scientific experiment, a scientific experiment

Floating Needle Think: Why do needles float on the water?

Materials: a bowl of water, needles, forks, liquid detergent.

Operation: 1. Pour a glass of water into a cup.

2. Use a fork to carefully place a needle on the surface of the water2. Slowly remove the fork, and the needle will float on the surface of the water.

3. 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 so that it does not sink. Surface tension is the cohesive connection formed by water molecules.

This cohesive connection is due to the fact that a certain part of the molecules is attracted together, and the molecules are squeezed against each other to form a thin film. This layer of film is called surface tension, and it holds objects that are supposed to sink.

2. The detergent reduces the surface tension, and the needle cannot float.

Description: The needle is dangerous, please ask your parents to help you operate.

Dip the end of a toothpick in shampoo and place it in water, and you'll find interesting phenomena.

Electrified newspapers.

Think: Without glue, tape, or other adhesive things, newspapers can stick to the wall and not fall off. Do you know why?

Materials: 1 pencil; 1 newspaper

Steps: 1Newspaper, spread the newspaper flat on the wall.

2.After quickly rubbing the side of the pencil on the newspaper a few times, the newspaper fell off as if it were glued to the wall.

3.Lift a corner of the newspaper and let go, the lifted corner will be sucked back by the wall.

4.Slowly tear the newspaper off the wall and listen for the static electricity.

Instructions: 1Rub the pencil to electrify the newspaper.

2.Electrified newspapers were sucked into the wall.

3.When the air in the house is dry (especially in winter), if you remove the newspaper from the wall, you will hear the crackling sound of static electricity.

Charged balloons.

Think: When do two balloons attract each other, and when do they repel each other?

Ingredients: 2 balloons, 1 string, 1 cardboard.

Operation: 1 Inflate the two balloons separately and tie a knot in the mouth.

2 Connect the two balloons with a thread.

3 Rub a balloon on your hair (or cardigan).

4 Lift the middle of the rope and the two balloons immediately separate.

5 Place the cardboard between the 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.

2 The electricity on the two balloons causes them to be attracted to the cardboard.

Magic toothpicks.

Think: Will a toothpick in water swim with a sugar cube placed in water, or with soap placed in water?

Ingredients: toothpick, a basin of water, soap, sugar cubes.

Operation: 1Place the toothpick carefully on the water.

2.Place the sugar cube in a basin of water, away from the toothpick. The toothpick will move in the direction of the sugar cube.

3.Change a basin of water, carefully place the toothpick on the surface of the water, and now put the soap in the basin closer to the toothpick. Toothpicks will stay away from soap.

Explanation: When you put the sugar cube in the center of the basin, the sugar cube will absorb some water, so there will be a small flow of water in the direction of the sugar cube, and the toothpick will also move with the water flow. However, when you put soap into the basin, the surface tension on the edge of the basin is stronger, so the toothpick is pulled outward.

Create: Please try to see which direction the toothpick will swim if you swap sugar and soap for something else.

Bottles that will eat eggs.

Think: Why can eggs get through bottles smaller than yourself?

Ingredients: 1 hard-boiled egg, 1 flask, a few pieces of paper, 1 box of matches.

Operation: 1. Peel off the shell of the cooked egg.

2. Tear the paper into long strips.

3. Light the paper and still put it in the bottle.

4. As soon as the fire is extinguished, immediately buckle the egg to the mouth of the bottle and remove your hand immediately.

Explanation: 1. When the paper has just been burned, the bottle is hot.

2. After the egg is buckled at the mouth of the bottle, the temperature inside the bottle gradually decreases, the pressure inside the bottle becomes smaller, and the pressure outside the bottle is large, and the egg will be squeezed into the bottle.

On Sunday, the science teacher gave us an assignment to do an experiment on rusting nails. The teacher asked us to prepare three plates and three iron nails to see what factors are related to the rusting of iron nails.

When I got home, I couldn't wait to find three old plates and three iron nails that I didn't use to experiment. I put a nail in the first plate and marked it with the number 1; On the second plate, iron nails were placed, and the vegetable oil was poured and marked with the number 2; Put iron nails in the third plate, pour some more water, and mark the number 3. The preparations are done, all that's left is to be patient and observant.

The next morning, as soon as I got up, I hurried to look at the three plates, and nothing changed. After waiting for another two days, it seems that nothing has changed. What a hurry!

It takes a lot of patience to do this experiment. But according to the teacher, the No. 3 plate should have changed a little, right? I took a toothpick and gently flicked the nail in the third one, and the water stained looked like a little rust.

On the fourth day, I went to see three more plates, and the changes were not too big, and after another two days, the nails in the third plate were more rusty, and the nails in the other two plates were not rusty at all. I'm a little anxious, how is it different from what the science books say?

With questions, I went to the school and asked the teacher. "Teacher, according to the science books, the nails in the plate without water will rust a little after a few days, but why hasn't the experiment changed at all? "The teacher asked me about the experiment and told me that in fact, the change of the nails was also related to the humidity in the air.

If the air is dry during this time, the nails placed on an empty plate will not change much after a few days. You must be patient enough to wait for the results of the jujube stove that you expected. Oh, I see!

Through this experiment, I not only learned that the rust of iron nails is related to the oxygen in the air and the water in the air, but also that sometimes I have to look at the results according to the changes in other conditions. The science experiments are really interesting, and I will do more experiments when I have the opportunity in the future.

Tools Raw Materials:

1 cup of hot and cold water, 1 color of ink (pigment).

1. Material preparation: 1 cup of hot and cold water, 1 color of ink (pigment).

2. Pour hot water into one of the cups and cold water in the other.

3. Drip ink into the cup of cold water first, and then drip ink into the cup of hot water. (At the same time drops will be better contrasts).

4. We can observe that the pigments in the cup filled with hot water begin to diffuse, and the ink stains in the cup filled with cold water are still condensed together, and the color of the hot water is also stronger.

Experimental principle

Due to the high temperature of the hot water and the violent movement of the molecules, if you drop two drops of ink into the cold water cup and the hot water cup, you will see that the ink in the hot water spreads quickly.

This suggests that the irregular motion of the molecule is related to the temperature, and the higher the temperature, the more intense the irregular motion of the molecule. Because the water molecules of hot water move faster than cold water. The water molecules in the hot water can run into the ink relatively quickly and merge with the ink.

Turning over a set of good stuff this afternoon, what is it? Haha, it's a science experiment package.

This is a baby, the first thing I took out was a small test strip, but I didn't bring a contrast color card, what can I do? Ask Mom.

Mom, you see, this inferior product was only given a test strip, not a contrast color card. ”

Hehe, I knew that this wonderful mother, at the critical moment, would definitely be useless.

So what to do, there is some knowledge, if you don't understand it, you don't understand. Oh yes, back to the textbook, this is the matching school bag, and the knowledge is definitely in the textbook.

Haha, sure enough, the color card is clearly printed on the textbook, and it also explains the use of these test strips in detail. That's going to be easy, it.

I prepared white vinegar, laundry detergent, tap water, purified water, baking soda, cucumber juice and apple juice, as well as sodium acetate and calcium lactate.

And guess what? This solution of sodium acetate and calcium lactate turned out to be alkaline, what about the acid? Bullying small children.

That white vinegar and apple, needless to say, are acidic. Laundry detergent and baking soda are definitely alkaline. There is still a difference between tap water and pure water, the tap water in our community is weakly acidic, and pure water is really nothing, it is neutral. Cucumber juice does not react, it should also be neutral.

The second experiment is the most interesting, one that proves that air really exists. That's interesting. Prepare a candle, a plate, an empty bottle of mineral water, a little water.

Light the candle and stick it to the bottom of the plate, then pour water into the plate and cover the candle with an empty mineral water bottle.

And then a miracle happened!

Haha, after a while, the candle went out, and the water on the plate poured into the bottle with a clatter, and the candle floated up. It startled me at the time, and then I burst out laughing. It turns out that air really exists, and when the candle burns, it really consumes some of the air, which is oxygen.

Then the air pressure inside and outside the bottle changed, and the water poured in, and it turned out that we could see the air in this way, which was so interesting.

Now you know why I didn't use a glass but a mineral water bottle, right? Because the mouth of the mineral water bottle is very thin, the water is particularly obvious when it pours in, which makes it shocking and the memory clearer, right?

I must not let my mother hear this, and when she hears it, she will say that I am talking nonsense. Because the reason why I used the mineral water bottle was because I couldn't find the glass, and I didn't expect it to have an unexpected effect.

Of course, we also did some other small experiments, but I didn't think it was a big deal, so I won't mention it.

It seems that the science is still quite interesting, and you can play it later.

The 100 science experiments and their principles are as follows:

1. Chopsticks Timmy inserts chopsticks into a bottle full of rice and finds that one chopstick can lift the whole bottle of rice, which is caused by the friction between chopsticks and rice and between rice.

2. The white paper ruler is a magical little experiment, the white paper is spread on the edge of the half suspended on the ruler of the desktop, the white paper and the desktop can be regarded as full contact, they have less air between the cherry traces, when the weight hits the ruler, due to the action of the force, the ruler will pick up the white paper, at this time the air pressure between the white paper and the desktop is less than the atmospheric pressure, and the atmospheric pressure will suppress the white paper and not let the ruler bounce up.

3. The bouncing bubbles are prepared into a mixed solution of water and dish soap according to the ratio of 3:1, and the solution is taken with a straw, and the bubbles can be blown out, but the bubbles are easier to break; Mix the glue and the mixed solution in a ratio of 1:2, and then use a straw to take the solution and blow out the bubbles.

Touching the bubble with gloves not only makes it difficult to break, but it also bounces when touched by hand.

Decryption moment: The bubbles in the bubble are explosive due to the evaporation of water, and they will become very sticky after adding glue, and the water will not evaporate easily, and the strength of the bubble film will increase, so it can jump on the back of our hands.

4. The spine rot temperature of the candle flame The materials needed today are: Lighter candle Toothpick: Light the candle first, and slowly approach the toothpick to the flame This part can help mom and dad Oh, now observe the traces of flame burning, the candle flame is divided into three ......

5. Chopsticks Timmi: The materials you need to use today are: funnel, narrow-mouthed bottle, a chopstick, a few pieces of rice, pour the rice into the bottle through the funnel, try to fill the bottle, insert the chopsticks into the center of the bottle, and be careful not to touch the bottle as a ......

6. The materials needed today are: a small tray, a stirring rod, a small measuring cup of pigment dropper, a few water, drop the pigment into the small measuring cup, and add the clear ......