1. Tucao "immortal spirit":
Experimental supplies: pointed glass tube, alcohol lamp, colored plastic tube, absorbent cotton.
Gasoline, soap, glycerin.
Experimental principle: gasoline vapor can be ignited. When gasoline is mixed with air, it will burn violently and explode in case of fire.
Experimental operation: put a colored plastic tube on a 20 cm long pointed glass tube, and put a cotton ball soaked in gasoline in the tube. Aim the suction tube at the flame of the alcohol lamp and blow into the other end of the glass tube. Gas comes out of the nozzle and burns when it meets fire. Leave the flame and continue to burn. If the blowing force on the glass tube is slightly larger, the flame can be bright blue at a distance of 4 ~ 5 cm from the tip, which is very beautiful.
At this point, the tip of the glass tube is immersed in soap, and a small amount of glycerol drops. After taking it out, blow air on the other end of the glass tube. When soap bubbles appear in series in the air, it is very interesting to ignite one soap bubble after another with burning alcohol cotton balls, and then emit a series of slight explosions and fireballs.
2. The fire went out:
Experimental supplies:
100 ml beaker, brush, brush, glass rod, glass plate, color map.
Borax concentrated solution, alum saturated solution, gunpowder cotton, acetone, aluminum powder.
Experimental principle:
After the picture is treated with borax and alum solution, there is a protective layer on the picture that is not easy to burn. Powder cotton burns quickly and the picture will not burn out.
Experimental operation:
Take a color picture, paint a layer of borax solution with a brush, dry it and then paint a layer of alum solution, and dry it for later use.
Put gunpowder cotton into a small beaker, add acetone and aluminum powder, and stir well. Then brush the acetone thick solution of gunpowder cotton on the glass plate, and the brush area is slightly larger than the picture. Brush it 3 ~ 4 times repeatedly, dry it, then take it off and stick it on the picture. At this time, the gunpowder quilt match was lit. When the gunpowder cotton burned out quickly, a beautiful picture appeared before us.
3. Can't burn paper fire:
Experimental supplies:
Evaporating dish, glass rod, tweezers, paper, carbon disulfide, carbon tetrachloride.
Experimental principle:
Carbon disulfide is a flammable liquid, but carbon tetrachloride cannot burn. The combustion of carbon disulfide produces carbon dioxide and sulfur dioxide, and gives off heat at the same time.
Because there is carbon tetrachloride in it, carbon tetrachloride takes away a lot of heat when it volatilizes in large quantities, so the flame temperature decreases and the ignition point of the paper cannot be reached.
Experimental operation:
Pour 6 ml of carbon disulfide and 16 ml of carbon tetrachloride into an evaporating dish and stir evenly. Light blue flame can be seen after being ignited by fire. Then put an ordinary piece of paper on the flame with tweezers, but the paper won't burn.
What are the interesting chemical phenomena in life? Duck with automatic long hair:
Cut the aluminum skin into duck shape (rabbit, cat, mouse ... whatever), dip a cotton swab in HgNO3 solution and coat it on the aluminum skin. After a few minutes, dry the mercury nitrate on the aluminum skin. Then you can see that the aluminum duck automatically grows white hair!
Experimental principle: aluminum is an active metal, but the reaction between aluminum and air is prevented because of the dense oxide film on the surface of aluminum. After coating with HgNO3 solution, the dense oxide film was destroyed and Al-Hg alloy was formed, which made it impossible to form a dense oxide film on Al surface. Al can continuously react with oxygen in the air to produce white Al2O3.
Precautions: HgNO3 is a highly toxic compound, so we should pay attention to the protective measures during the experiment!
Build an "underwater garden"
Sodium silicate (Na2SiO3) was dissolved in water to make water glass with 40% solute mass fraction. When salt particles, such as chlorides of cobalt, iron, copper, nickel and lead, sulfates of aluminum, iron, copper and nickel, and nitrates of cobalt, iron, copper and nickel are gently added to water glass (be careful not to mix them), colorful "flowers" will slowly grow.
Magic stick illumination
Can a glass rod be used instead of a match to light an alcohol lamp?
Experiment: put a small amount of potassium permanganate crystal on the mirror (or glass), drop 2 or 3 drops of concentrated sulfuric acid on potassium permanganate, dip it with a glass rod, and touch the wick of the alcohol lamp, and the alcohol lamp will light up immediately.
Protein trace
Take an egg, wash the oil on the surface and dry it. Dip the brush in acetic acid and write on the eggshell. After the acetic acid volatilizes, cook the egg with dilute copper sulfate solution, and peel off the eggshell after the egg cools, leaving clear blue or purple handwriting on the egg white, but leaving no trace on the eggshell.
This is because acetic acid can dissolve a small amount of protein after dissolving eggshells. Egg white is a globulin composed of amino acids, which is hydrolyzed under weak acidic conditions to produce peptides and other substances, and the peptide bonds in these substances are complexed with Cu2+ to appear blue or purple.
Water-fire compatibility
Fill a glass with half a glass of water, put a dozen potassium chlorate crystals at the bottom of the water, and then put a few small yellow phosphorus in the potassium chlorate crystals with tweezers. Then use a glass straw to suck a little concentrated sulfuric acid and transfer it to the mixture of potassium chlorate and yellow phosphorus, and then there will be a fire in the water. If there is fire in the water, isn't it "compatible with water and fire"?
Where's the secret? Putting potassium chlorate into water, wherein potassium chlorate is an oxygen-containing compound; Then add yellow phosphorus, which is very flammable. Because it is isolated from oxygen in the air in water, it will not spontaneously ignite. However, when concentrated sulfuric acid is added, concentrated sulfuric acid reacts with potassium chlorate to form chlorate, which is unstable and releases oxygen. Oxygen reacts with yellow phosphorus to burn. This reaction is particularly intense, so it can also be carried out in water, so that fire and water are in the same cup. Phosphorus is oxidized into phosphorus pentoxide, which reacts with water to produce phosphoric acid.
blow a fire
Experimental principle Sodium peroxide can react with carbon dioxide to produce oxygen and give off a lot of heat, which makes cotton catch fire.
Experimental supplies evaporating dish, glass rod, tweezers, slender glass tube. Na2O2, absorbent cotton.
experimental procedure
1. Spread a small amount of Na2O2 powder on a thin layer of absorbent cotton and gently press it with a glass rod to make Na2O2 enter the absorbent cotton.
2. Gently roll the absorbent cotton with tweezers on Na2O2 and put it in an evaporating dish.
3. Blow absorbent cotton slowly with a slender glass tube. Observe the phenomenon
What interesting physical and chemical experiments are there in life? What are the interesting chemical phenomena in life?
1, small charcoal dance
Dear students, you must like chemistry very much, so you can do an interesting little experiment by yourself. The theme of this experiment is dancing with small charcoal. Take a test tube, fill it with 3-4g solid potassium nitrate, then fix it upright on an iron frame with an iron clip, and heat the test tube with an alcohol lamp. When the solid potassium nitrate gradually melts, take a piece of charcoal the size of a small bean, put it in a test tube and continue to heat it. After a while, you will see the small carbon block suddenly jumping up and down on the liquid level in the test tube, and then turn it over by itself, like dancing, giving off a fiery red light, which is very interesting. Please enjoy the beautiful dance of Little Charcoal. Can you answer why Xiao Tan dances?
answer
It turned out that when the small charcoal was just put into the test tube, the temperature of potassium nitrate in the test tube was low, so the small charcoal was still lying there. After heating the test tube, the temperature rises to make the small charcoal reach the ignition point. At this time, there is a fierce chemical reaction with potassium nitrate, which releases a lot of heat and makes the small charcoal burn and glow immediately. Because potassium nitrate decomposes at high temperature to release oxygen, this oxygen immediately reacts with small charcoal to generate carbon dioxide gas, which pushes small charcoal up at once. After the charcoal jumped up, it was out of contact with the potassium nitrate liquid below, the reaction was interrupted, and carbon dioxide gas was no longer produced. When the small charcoal falls back to potassium nitrate due to gravity, it reacts again and jumps up for the second time. This cycle, small charcoal kept jumping up and down.
2. Sugar turns into "black snow"
White sugar is a substance that people often eat. It is small white particles or powder, like snow in winter. However, I can turn it into "black snow" right away. If you don't believe me, please take a look at the following experiment. Put about 5g of white sugar into a 200ml beaker, and then drop a few drops of heated concentrated sulfuric acid. Suddenly, the sugar turned into a pile of fluffy "black snow", and the volume of the "black snow" gradually increased, even overflowing the beaker. Sugar suddenly became
Black Snow, that's interesting. Who knows the secret here?
answer
It turns out that there is a chemical reaction between sugar and concentrated sulfuric acid called dehydration. Concentrated sulfuric acid has a particularly eccentric hobby, that is, it especially wants to combine with water. It makes full use of the moisture in the air, even the moisture in other substances. As soon as we meet, it will take the water away. Sugar is a kind of carbohydrate (c 12h22o 1 1). When it meets concentrated sulfuric acid, the water in the sugar molecules is immediately taken away by it, and the rest is the poor sugar with carbon, which turns black. Concentrated sulfuric acid is not satisfied with taking water for its own use. It uses another skill-oxidation, which oxidizes part of the residual carbon in white sugar to generate carbon dioxide gas to escape.
c+2h2so4=2h2o+2so2+co2
Due to the escape of carbon dioxide and sulfur dioxide gas produced after the reaction, the volume is getting bigger and bigger, and finally it becomes fluffy "black snow". In the "battle" of concentrated sulfuric acid against water, it is an exothermic process, so it gives a sneer and provides heat for the process of continuous oxidation of carbon by concentrated sulfuric acid.
3, no light bulb
An interesting chemical performance in a middle school is going on enthusiastically, and one of the programs is particularly eye-catching I saw a 200-watt light bulb hanging on a wooden pole, giving off dazzling white light. As far as brightness is concerned, ordinary electric lights are far behind. However, this light bulb has no wires, because it is a light bulb without electricity. Please think about it, where is the secret of this light bulb without electricity?
answer
It turns out that this bulb is filled with magnesium bars and concentrated sulfuric acid, and they have a fierce chemical reaction in the bulb, producing exothermic light. As we all know, concentrated sulfuric acid has strong oxidation ability, especially when it comes to some metals. Magnesium metal is particularly easy to be oxidized, so they are naturally "a match made in heaven". As soon as they meet, they will have a chemical reaction immediately:
Magnesium +2h2so4 (concentrated) = = magnesium sulfate +SO2+2h2o
In the process of reaction, a lot of heat is released, which makes the temperature in the bulb rise sharply and makes the magnesium bar reach the ignition point quickly. Under the condition of sufficient oxygen supply from concentrated sulfuric acid, magnesium bars burn more violently, just like flares.
4, water purification expert-alum
Speaking of alum, people are familiar with it, and some people call it alum, and the chemical name is potassium aluminum sulfate. But alum is not only used as a chemical raw material, but also a water purification expert! Once we went to the countryside for investigation, and when we were cooking lunch, we found that the water in the tank was too muddy to use. Just as we were worried, technician Zhang from the agricultural technology station came. Seeing that there was nothing we could do, he immediately took out a few pieces of alum, ground it into fine powder and sprinkled it in the jar. After a while, the water in the tank became clear and transparent. Although it has been several years, it is still fresh in my memory. However, I still don't understand why. Please explain it to me.
answer
It turned out that the mud dust in the water was "caught" by alum and sank to the bottom of the pool together. So, why can alum "catch" the mud and dust in running water? This should start with the turbidity of water itself. Tiny dirt and dust in water are not easy to settle down because of their light weight, and they "swim" in the water, making the water turbid. In addition, these tiny particles have another feature, that is, they like to pull some ions in the water to their side, or ionize some ions themselves, thus turning themselves into charged particles, which are often negatively charged. Because like charges repel and opposite charges attract, these negatively charged particles repel each other and cannot get together, so there is no chance to form larger particles and settle down. Alum, on the other hand, has a strange ability to make these inaccessible particles run together. When alum meets water, there will be a hydrolysis reaction with potassium sulfate as the supporting role and aluminum sulfate as the protagonist. Aluminum sulfate reacts with water to form a white flocculent precipitate-aluminum hydroxide. The generated positively charged aluminum hydroxide "hugs" each other as soon as it comes into contact with negatively charged sludge and dust particles. In this way, many particles gather together, and the particles get bigger and bigger, and finally they all sink to the bottom of the water, and the water becomes clear and transparent.
Simply put, it is the hydrolysis of aluminum ions.
5. Boiled eggs with lime
The school building of Nanjing primary school is going to be repaired again, and the workers and teachers are arguing like boiling water. HuiQing and Yan Li stood watching curiously, chatting. Hui Qing said, "Look at this heat, you can definitely cook the eggs." Li Yan said: "Impossible." To find out, they took an egg from home and buried it in a pile of steaming lime. After a while, the egg exploded with a bang. They are even more puzzled when they see this situation. They thought about it and didn't understand what was going on. Who can explain it to them?
answer
There is a simple reason. The chemical name of quicklime is calcium oxide, which becomes hydrated lime after adding water, and the chemical name is calcium hydroxide, commonly known as white ash. The process of converting quicklime into hydrated lime is called "digestion", which is an exothermic reaction:
6. Unstable sanitary ball
Speaking of fitness balls, everyone must be familiar with them. They are often used to kill moths in suitcases. However, what happens when you put it in an aqueous solution containing acetic acid and baking soda? At first, it slept at the bottom of the cup. After a while, it became restless, but it jumped up and down in the water like crazy. Who knows why?
answer
After this chemical reaction, the easily generated carbon dioxide gas becomes tiny bubbles attached to the bottom or wall of the cup, and the whole body of the sanitary ball is covered by these bubbles. Carbon dioxide is lighter than water, so it will rise to the surface. Once the bubbles on the sanitary ball reach a certain level, they will rise straight like a drowning person pulling a lifebuoy. When the sanitary ball rises to the water surface, the small bubbles attached to the sanitary ball burst due to the decrease of pressure, and the sanitary ball recovered its original proportion and lost its "life buoy", so it sank back to the bottom of the cup, stuck enough small bubbles and floated up again. In this way, the sanitary ball will run around.
7. The origin of "bhc" powder name.
An insect pest occurred in a wheat field in the suburbs. In order to resist disasters and kill insects, farmers sprayed a chemical pesticide powder called "bhc". At this time, clever classmate A solemnly asked classmate B: "Why do you say this pesticide is called' BHC' powder?" "I don't know yet, because when this pesticide was invented, scientists experimented 666 times." Student B answered confidently. A classmate retorted, "What you said is wrong. It is said that this pesticide is made of 666 kinds of drugs, so it is called' BHC' powder. The two students are arguing with each other. ...
Please comment. Which of them is right? Why?
answer
Neither of the two students is right. This insecticide is produced by the reaction of a chemical called benzene with chlorine under ultraviolet radiation.
C6h6 13C 12 = C6H6Cl6
As can be seen from the molecular formula of the generated BHC powder, its molecule consists of six carbon atoms, six hydrogen atoms and six chlorine atoms, so it is called BHC powder.
8. The magical use of ammonium chloride fireproof cloth
Dear students, I soaked an ordinary cotton cloth in the saturated solution of ammonium chloride. After a while, I took it out to dry and made a fireproof cloth. If you light this chemically treated cloth with a match, it won't light and white smoke will come out. Please tell me, what is the reason?
answer
It turns out that the surface of this chemically treated cotton cloth (fireproof cloth) is covered with crystal particles of ammonium chloride, which has a strange temper, that is, it is particularly afraid of heat. When heated, it will undergo chemical changes and decompose two kinds of non-combustible gases, one is ammonia and the other is hydrogen chloride.
NH4Cl-& gt； Nh3 (gas) +HC 1 (gas)
These two gases isolate cotton cloth from air, and cotton cloth can't burn without oxygen. When these two gases protect cotton cloth from fire, they meet in the air and recombine into small crystals of ammonium chloride, which are scattered in the air like white smoke. In fact, ammonium chloride is a good expert in fire prevention. The stage scenery of the theater and the wood on the ship are often treated with ammonium chloride to achieve the purpose of fire prevention.
9. The ups and downs of eggs
Fill a big beaker with dilute hydrochloric acid solution, then put a fresh egg in the beaker, and it will immediately bottom out. After a while, the egg rises to the liquid level again, and then sinks to the bottom of the cup. After a while, the egg floats to the liquid level again, and so on many times. Please analyze it. What is the reason?
answer
Because the main component of egg shell is calcium carbonate, it will react with dilute hydrochloric acid to generate calcium chloride and carbon dioxide gas.
Cac0312hc1= CAC121c02 (gas) 1H20.
The bubbles formed by carbon dioxide gas are tightly attached to the eggshell, and the buoyancy generated makes the eggs float. When the egg rises to the liquid level, the pressure on the bubbles is less, some bubbles burst, and carbon dioxide gas diffuses into the air, thus reducing the buoyancy and the egg begins to sink again. When it sinks to the bottom of the cup, the dilute acid constantly reacts with the eggshell, constantly producing carbon dioxide bubbles, thus making the egg float again. This cycle is repeated. Finally, when the shell of the egg comes into contact with hydrochloric acid, the reaction stops and the up-and-down movement of the egg stops. But at this time, because the liquid in the cup contains a lot of calcium chloride and residual hydrochloric acid, the specific gravity of the liquid is greater than that of the egg, so the egg finally floats on the liquid.
What are the interesting phenomena in life? 1. When the quartz clock hanging on the wall is dead, its second hand often stops at the position of "9" on the dial. This is because the second hand is most hindered by the large torque at the "9" position.
2. Sometimes, when tap water flows from the adjacent faucet, it occasionally makes bursts of noise. This is because the water pipe vibrates when the water rushes out of the tap.
3. When taking pictures in front of the TV screen, turn off the camera flash and indoor lighting to make the pictures clearer. Because the reflected light of the flash lamp and the illuminating lamp on the TV screen will interfere with the transmitted light of the TV picture.
At the same temperature, frozen pork thaws faster in water than in air. At the same temperature, hot nails cool faster in water than in air. A cup filled with boiling water cools faster when immersed in water than when immersed in air at the same temperature. All these phenomena show that water has better heat transfer performance than air.
When there is cold water in the pot, the water droplets attached to the outer surface of the bottom of the pot can only be dried up after a long time on the flame, and will only boil when it is dried up. This is because the water droplets, the pot and the water in the pot keep heat conduction, and the temperature is similar. As long as the water in the pot is not boiled, the water droplets will not boil, and the water droplets will gradually be dried by evaporation on the flame.
6, out of shape mirror, the farther away from the mirror, the more out of shape. Because the image in the mirror is formed by the reflection of the silver-plated surface behind the mirror, uneven silver-plated surface or uneven glass thickness will lead to aliasing. Distorted mirror, the farther away from the mirror, the greater the deviation of reflected light from the normal position of the silver-plated surface, and the more deformed the mirror.
7. There are several small holes communicating with the outside world on the side of the gas nozzle of the natural gas furnace, but natural gas will not be ejected from the side holes, but only from the nozzle. This is because the air velocity at the nozzle is high, and according to the principle of fluid mechanics, the air surface pressure is lower than the atmospheric pressure outside the side hole, so the natural gas will not be ejected from the side hole of the nozzle.
8. After blowing the balloon, hold the mouthpiece with your hand and then suddenly release it. The air in the balloon is ejected and the balloon moves due to recoil. You can see that the route of balloon movement is tortuous. There are two reasons: first, the thickness and tension of the inflated balloon are uneven everywhere, which makes the balloon contract unevenly and swing around when it is deflated, thus the movement direction changes constantly; Second, the shape of the balloon is constantly changing during the contraction, so the air velocity on the surface of the balloon is also constantly changing during the movement. According to the principle of fluid mechanics, the air pressure on the surface of the balloon is constantly changing, so the balloon swings and the direction of movement is also constantly changing.
9. When the ceiling fan rotates normally, the tension at the suspension point is smaller than when it does not rotate. The greater the rotational speed, the more the tension decreases. This is because when the ceiling fan rotates, the air has an upward reaction force on the ceiling fan blades. The greater the speed, the greater the reaction force.
10, electric furnace "combustion" is the conversion of electric energy into internal energy. Without oxygen, it can only oxidize electric furnace wires, shortening service life.
1 1. Even if there is no wind, the path of paper dropping is tortuous. This is because each part of the paper has different convexity and concavity and shape, so in the process of falling, the air speed on its surface is different. According to the principle of fluid mechanics, there is uneven air force everywhere on the paper, which changes with the movement of the paper, so the paper keeps rolling and falling zigzag.
12 Take a piece of paper and push it hard with both hands. The position where the paper is torn is always not in the middle, but next to the finger.
Electrical phenomena:
Phenomenon 1: The weather is dry. When you get up in the morning to comb your hair, your hair will float with the comb.
Phenomenon 2: When you take off your sweater at night, you will hear the sound of "scratching", sometimes accompanied by sparks.
Phenomenon 3: After rubbing repeatedly on the scalp with a plastic ruler or pencil box, it is close to the paper, and the paper is "sucked" away by the plastic ruler.
Phenomenon 4: After the foam is dispersed by hand, the small foam particles stuck on the hand cannot be thrown away.
And:
Scene 1: There is a lot of dust on the lower surface of the ceiling fan. It is reasonable to say that there will be no dust falling from the lower surface of the ceiling fan, but why is it so dirty?
Scene 2: Wear chemical fiber clothes, especially vacuuming, especially easy to get dirty.
Scene 3: There will be a layer of dust on the surface of TV and computer monitors after long-term use. When you turn off the TV, if you put the back of your hand close to the TV screen, you will find that the hairs on the back of your hand will stand up one by one.
Interesting chemical phenomena in life. . . Dropping vinegar on eggshells will produce small bubbles.
Experimental principle: aluminum is an active metal, but the reaction between aluminum and air is prevented because of the dense oxide film on the surface of aluminum. After coating with HgNO3 solution, the dense oxide film was destroyed and Al-Hg alloy was formed, which made it impossible to form a dense oxide film on Al surface. Al can continuously react with oxygen in the air to produce white Al2O3.
What are the interesting biological phenomena in life?
(1), algae mostly live in water, and a few live in wet places; Bryophytes live in a dark and humid environment. (2) From the morphological structure, bryophytes have no roots, stems and leaves; Algae plants have no differentiation of roots, stems and leaves, and all parts of the body can absorb water and inorganic salts, so they do not need special organs for absorption, transportation and photosynthesis. Algae plants have stems and leaves, but only rhizomes, which only fix the plants and do not absorb them. There are no ducts on the stems and no veins on the leaves, so the plants are short. (3) From the above problems, it can be seen that bryophytes have no ducts in their stems and no veins in their leaves, so their plants are short. (4) Because the leaves of bryophytes have only one layer of cells, they can absorb toxic gases such as sulfur dioxide from the back and abdomen. Algae: No differentiation of roots and leaves. (3) Moss: rootless, unable to absorb a lot of nutrients; There is no supporting tissue in the stem. (4) Sensitive to toxic gases, it is an indicator plant for monitoring air pollution.
What are the interesting scientific experiments in real life: interesting chemical phenomena in life 1, dancing with Xiao Tan Dear students, you must like chemistry very much, so do an interesting little experiment yourself. The topic of this experiment is dancing with small charcoal.
Interesting chemical experiment, magical bottle
[experimental principle]
Acid indigo dye can be reduced to a reduced state by sodium sulfide in solution, showing yellow color. When oscillating, the reduced yellow indigo can be oxidized into green indigo oxide by oxygen in the air. There are a series of transition colors between the two colors.
[experimental operation]
Take a colorless transparent 500 mL glass bottle with a sealed cover, add 2 g sodium sulfide and 200 mL distilled water to make a solution, then add 1% acid indigo solution dropwise until the whole solution turns green, cover tightly, and let it stand, and the solution gradually turns from green to brown → red → orange → yellow. Shake the bottle, the solution will gradually change from yellow to orange, red to brown and green. Let stand and repeat the previous discoloration, which can be repeated several times.
[Key to success or failure of experiment and matters needing attention]]
The experiment should be carried out at 25℃ ~ 30℃. If it is cooked in winter, it should be heated in a warm bath.