What does water look like during science experiments in third grade?

There are more than a dozen experiments as follows.

Raising fish in boiling water

You will need: a water test tube (or a longer glass) an alcohol lamp from small fish

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Do this: in a test tube or longer glass Fill half a cup of water in the glass, put a few small fish in the water and attach the test tube at an angle so that the Water just reaches the mouth of the cup (as shown in the picture). Place an alcohol lamp under the mouth of the cup and start heating the water in the cup (be careful, only the top of the test tube can be burned) until the top of the cup is steaming . See how the little fish is formed. that you do (if there is ice, you can put some in the water).

Think about it: why can small fish live peacefully in the steaming water at the top? Has the ice cream melted?

Get creative: take the “burnt” fish home and breed it to see how long it lasts.

Say to yourself: Heat the water in the upper part of the test tube. The water will not sink to the bottom after being heated. The thermal conductivity of water is poor and the water at the top transfers heat to the bottom, which is a slow process. So even though the water in the top half of the test tube was boiled, the bottom was still cold. In this way, fish can definitely be raised in “boiling water”. (Note: This experiment may be dangerous and requires adult guidance.)

Light a lamp in the water

You need: water from the pool to candles

Do this: place a relatively thick candle stick at the bottom of the basin, pour in a little water and keep the surface of the water a small distance from the surface of the candle (without immersing the candle). Light a candle andSee if it burns below the surface of the water.

Think: why can lights be turned on underwater? Get creative: Test whether the candle burns deeper below the surface in hot water or in ice water. (Special reminder: This experiment may be dangerous and requires

adult guidance.)

The water goes to a higher place

It you need: a basin of water, candle, glass< /p>

Do this: stick the candle to the bottom of the basin and fill the basin with an appropriate amount of water. Light a candle, and when the fire is very strong, hold the candle with a glass and see what happens.

Think: How can water rise? Get creative: Is there a relationship between the height of the water rise and the size of the fire? Does this have anything to do with the size of the glass? How to verify it experimentally?

Tell yourself: since the burning of the candle consumesoxygen in the cup, the volume of gas in the cup becomes smaller, the air pressure decreases, and the external air pressure squeezes the water in the cup. , therefore "the water rises". (Special reminder: This experiment may

be dangerous and requires adult guidance.)

Don't worry about making your own soda

It you need: fresh lemon, cold boiled water, sugar Soda glass

Do this: Cut a lemon and squeeze the juice into the glass. Add an appropriate amount of water, then pour in a tablespoon of baking soda, shake gently to completely dissolve the baking soda, then add a little sugar. Try it, what does it taste like? Is there steam in soda prepared this way?

Think about it: why does soda have vapor in it?

Be creative: mix the ratio of lemon juice, baking soda, sugar and water to make the soda more delicious.

Tell yourself this: When baking soda and lemon juice are mixed, they react to produce carbon dioxide. The bubbles contained in sodas sold in supermarkets are also formed by carbon dioxide added to them under high pressure.

Hot and cold ink

You will need: Two glasses of hot water and cold water ink

Do this: Pour in some hot water in one of the glasses, Pour cold water into another cup and place a drop of ink in each cup.

Think about it: which mixes faster with ink, hot water or cold water? For what?

Be creative: If a person has a sprain, should they use hot or cold water to apply to the injured area? For what?

Tell yourself: Water molecules in hot water move faster than in cold water. Water molecules in hot water can penetrate more quicklyent into the ink and merge with the ink. (Special reminder: This experience may be dangerous and requires adult guidance.)

Comes and goes without a trace

You need:

Two of the same size bottles (one with lid, one without) of water

Do this: add the same amount of water to both bottles, cover one of the bottles and leave it another discovery, place the bottles in full sun on the windowsill and let them sit there for a few days. Take a look,

After a few days, which bottle holds more water, the bottle with a sealed lid or the bottle without a lid?

Think: why is this happening? Where did the water go?

Tell yourself:

When water is heated, the molecular movement accelerates and some water molecules in the opened bottle will be emitted into the air as water vapour. . This phenomenon is called “evaporation”.

Smoking ice

You need: Ice cubes (if it's not cold and there is no ice on the river, you can use your home refrigerator to make some freeze one piece) A jar with a lid Electric stove (others can be heated A stove will work too)

Do this: Put the ice cubes in the pan and place the pan on a hot stove. Cover the pan and let the ice cubes melt. Pay particular attention to ice cubes. Is there steam on one side but still ice on the other side? Touch it

Will the melted water be warm to your hands at this time? Continue heating until the water boils. Open the lid of the pot and look closely to see something coming out of the boiling water. After reading, immediately cover the pot. Turn off the hotplate

, remove the pan from the heat and let it cool. Discover the pot andsee what's on the lid.

Think about it: why isn't water hot when it first melts? What will become of the ice cube? Under what circumstances does water turn into steam? How does water vapor turn into water?

Tell yourself:

Solid ice melts into liquid water when heated. When water boils, water vapor appears. When the water vapor cools, it turns into water. (Special reminder: This experience may be dangerous and requires adult guidance.)

Life hangs by a thread

You need: water , salt, paper clips, cotton thread, matches, bowl

Do this: fill the bowl halfway with a bowl of water, then add table salt to the water and stir continuously until the salt can no longer melt. Attach a paper clip to one end of the cotton thread, then put the paper clip and cotton thread in salt water whileFew minutes, hang the cotton thread in the air and let it dry (it will take a while, please wait patiently until the cotton thread is dry). Use a match to light the cotton string of the paper clip. Observe what will happen? When the cotton thread is burned, will the paper clip fall off?

Think about it: why doesn't the paperclip fall when the cotton thread is burned?

Get creative: What will happen if cotton thread is soaked in other liquids, like sugar water, dried and then burned?

Tell yourself: Since there is a lot of salt on the cotton thread soaked in salt water, when the cotton thread burns, the salt will harden and form a hard salt crust on the outside cotton thread. Therefore, after the cotton thread burns, the salt crust will still be pulled and the paperclip will of course not fall off. (Note: This experience may be dangerous and requires the conadult.)

Ice bathtub

You will need: A glass filled with water Ice cubes

Do this: Place some ice cubes in a glass filled with water.

Think about it: does ice float or sink? When the ice cube melts, will the water overflow from the cup? For what?

Tell yourself: The density of ice is less than that of water, which means that compared to ice and water of the same size, ice is lighter than water. water. Ice therefore floats on water. When a certain amount of water turns into ice, its volume increases. When ice melts in water, its volume remains the same

as before. So the water level in the cup does not change when the ice cube melts. Completely "full"

You will need: Two glasses Sugar spoons Hot and cold water

Do this: Add cold water to the first glass, stirring as you go gradually add sugar to the cup with a spoonuntil the added sugar can no longer dissolve in the water and begins to settle to the bottom of the cup. Count

how many spoons of sugar you added. Add the same amount of hot water to the second glass, and while stirring, use a spoon to add sugar to the glass until the added sugar can no longer dissolve in the water and begins to settle at the bottom of the glass.

until. Count how many spoons of sugar you added to the hot water.

Think about it: what can dissolve more sugar, hot water or cold water? For what?

Be creative: what will appear in the cup when the hot water turns cold? Where does this sugar come from?

Tell yourself:

The water molecules in hot water can bind more sugar molecules together. When the sugar can no longer dissolve, this state is called saturation. When the solution cools, the excess sugar dissolved in theThe hot water will settle at the bottom of the cup.

Small fountain

You will need: Straw water Spoon Rubber stopper with holes Glass bottle

Do this: First boil half a basin of hot water, being careful not to boil it. Insert the straw into the hole of the rubber stopper so that most of the straw is exposed at the bottom of the rubber stopper, pour half a bottle of cold water into the glass bottle

, then plug the rubber. cork with the straw in the neck of the glass bottle. Insert most of the bottom end of the straw into the water and the fountain is ready. Put the glass bottle in a basin filled with hot water, hold the bottle and see if anything happens.

Think: why?

Be creative:

Think of other ways to create a fountain.

Tell yourself:

Hot water in the pooltransfers heat to the bottle, causing the air in the bottle to expand when heated, and the expanded air forces the water out of the bottle. (Special reminder: This experiment may be dangerous and requires adult guidance.)

No dripping water

You need:

Thick paper, scissors, straight needle, Cork, basin, large glass, pencil, adhesive tape

Do this:

Draw the silhouette of a diver on thick paper, then use scissors to cut out the paper figure and place it. on the cork Insert a straight pin into the cork, place the cut-out paper figure against the straight pin and glue it in place. Fill the basin halfway with water.

Find a cup slightly larger and taller than the paper man, place the cup upside down on the "diver's" head, carefully place the paper man and cup upside down. 'backwards in the water, and that the "diver" and the neck cutslowly all at the bottom of the pool. Take the cup out of the water and see if the paper man has water on it.

Think: why don't the paper figures get a drop of water?

Be creative: if you replace the paper man with something else (like a cartoon cat), will it get wet?

Tell yourself: When the paper man and the cup sink into the water together, the air in the cup blocks the water from entering the cup. Of course, the paper man can't stick to the cup. water."

Catch strange "fish"

You need: ice cubes, table salt, a small bowl of cotton thread

Do this: put a few pieces of ice in it. In the bowl, put the cotton thread on ice and sprinkle a little salt around it. After a few minutes, gently bring the cotton thread up and try to catch it. the ice cube

Think about it: why can we catch it.er ice cubes after spreading salt?

Be creative: Sprinkle other things on the ice cubes, like sugar and MSG. Can cotton thread catch ice cubes?

Tell yourself: Sprinkle salt on the ice and some of the ice will melt. But after a while, due to the lower temperature of the ice cube, the melted water will turn into ice again. In this way, the cotton thread placed on the ice will be frozen

and the ice can be fished.

Water will not flow to the lowest place

You need: thicker plastic paper, scissors, a glass bottle with a small neck

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Do this: Use scissors to cut a piece of glass bottles slightly larger than plastic wrap. Fill the bottle with water and place the plastic wrap over the cap. Cover the neck of the bottle with your palm, turn the bottle upside down, remove your hand and observeWhat will happen?

What's going on?

Think: Why doesn't the water flow downward?

Be creative: If you cover the neck of the bottle with something else, like a thicker piece of paper or a piece of glass, will the water flow out?

Tell yourself: the plastic paper blocks the air and prevents air from entering the bottle. In this way, the external atmospheric pressure prevents the water from flowing out of the bottle.

Water takes you “home”

You need: a piece of white paper, two glasses, a few books, a pair of scissors

Do this: Pour it into a glass. Fill the middle with half a cup of water and use a few books to support the cup. Use scissors to cut several thin strips of paper from the white paper, place one end of the paper strips into the upper cup and the other end into the lower empty cup. Observe the next morning to see whatthat is happening. Where did the water go?

Think about it: how can water move “at home”?

Be creative: try replacing the paper strips with other items, like fabric strips or plastic paper strips. Will the water come “home”?

Let me tell you: it's a hair phenomenon at work. The water slowly seeped into the other cup through the pores in the paper strip.

Water Mountain

You need: A glass of water, quarters

Do this: Fill the glass with water. Gently slide the edge coins into the cup, one, two, three...twenty coins...thirty coins...pay attention to the shape of the water surface.

Think: Why doesn't the water flow even though the surface of the water sticks out?

Be creative: What would happen if there was soapy water in the cup instead of water?

Tell yourself: this phenoleads is related to the surface tension of water. The surface of any liquid has a tension that makes it feel like it has an elastic “skin.” When a coin is dropped into the cup, the elastic “skin” of the water arches slightly. Because it can withstand a certain pressure, even if more pieces are inserted, it will not explode easily, so the water will not overflow. A raised “mountain of water” rises from the mouth of the cup.

"Floating on water"

You need: a bowl of water, a needle and paper napkins

Make this: fill the bowl with water, put the paper towel over the water and lay the needle flat on a paper towel. If the paper towel absorbs water and sinks to the bottom, will the needle sink with it?

Think about it: why can needles have “luminous power” and float on water?

Be creative: try it. Using super voltagehere water, can you hold other objects, like coins?

Tell yourself:

Water has surface tension and the needle can float on water.

Volcano water

You will need: Glass jar, red ink or food coloring bottle with lid

Do this: Fill the jar with glass with about four 3/3 cold water. Fill the bottle with hot water and add a few drops of red ink or food coloring. Place the bottle at the bottom of the glass jar and unscrew the cap.

Think about it: why does a small bottle of water erupt like a volcano?

Be creative: try it. Change the water in the glass jar to hot water and put cold water in the bottle. What will happen ?

Tell yourself: the hot water in the bottle is lighter than the cold water, so it will spurt out. (Note: This experiment may be dangerous and requires adult guidance.)

Delicious ice cream

You need: a towel, ice cubes, chocolate powder, a cup of salt, milk, cream, a large basin, a spoon

Do this: pour one spoonful of chocolate powder, two spoonfuls of milk and one spoonful of cream into the cup and stir. Place a layer of ice in a large bowl and sprinkle with more salt. Place the glass on salted ice. Add more ice around the glass and sprinkle with salt. Cover the large basin with a towel and let it sit for about an hour, stirring every few minutes.

Think about it: why can you make ice cream?

Be creative: are there other ways to make ice cream?

Tell yourself: salt melts ice quickly. Ice transformed into water is endothermic and absorbs heat from the cup, thereby freezing the drink.

Red, orange, yellow, green, blue, purple

You will beAway from: flashlight, rectangular tray, mirror, white paper, water

Do this: fill the tray with water and press the mirror against it, on the narrowest side of the board. Let the flashlight shine on the part of the mirror submerged in water. Place the white paper in front of the mirror, let it catch the light reflected from the mirror, and see what appears on the paper.

Think: Why do white papers appear in seven colors: red, orange, yellow, green, blue, and purple?

Be creative: do you have other ways to create a “rainbow”?

Tell yourself: Sunlight will be broken down into seven colors on the spectrum after being refracted by water. White light is refracted as it passes through the water layer. Since the different colors of light that make up white light form different angles after refraction, they will emit the water surface at didifferent positions and will finally project onto the white paper, forming a “rainbow”.

Plain water vs soil

You need: two cups of cement and soil, two thermometers

Do this: use cups to fill with soil and water, and measure water and soil temperature. Place the cup and soil in the sun. Measure their temperatures at regular intervals.

Think: Why does the temperature of the soil increase faster than that of the water? Let me tell you: the specific heat of water is higher than that of soil. That is, if equal parts of water and soil have the same temperature and are heated to the same temperature, the water needs more heat than the soil. . In the experiment, the water and the ground received the same amount of heat. The specific heat of the soil is lower, so its temperature rises more quickly.

Shipwreck oil "sea"

You will needoin: two small ice cubes two glasses of water cooking oil

Do this: put one of the ice cubes in the glass of water and another piece of ice in the glass of oil.

Think about it: Why do ice cubes float on water but sink in oil?

What will happen if you put ice in different liquids, like salt water, juice, gasoline, etc.? ?

Tell yourself: Ice is less dense than water, so ice cubes float on water. The density of ice is greater than that of oil, so the ice will sink into the "sea" of oil.

The Joy of Water

You will need: Seven glasses of the same size of metal rods of water

Do this: Pour a quantity equal in each glass Measure the water and place them on the table in a row. Lightly tap the rim of each cup with a pencil and listen carefully to the sound of each cup.

Think: why does each cup ringdifferently?

Be creative: adjust the amount of water and see if you can create the seven tones 1 2 3 4 5 6 7.

Say to yourself: press the edge of the cup, the cup will vibrate and make a sound. The less water there is, the more frequently the cup will vibrate.

Water used by astronauts is used in fuel cells

We are currently experimenting with full water circulation, which means that the water on the space station is completely recycled, including sweat, urine, etc., and Water and oxygen are separated. The energy can be solar energy, and the CO2 and urea exhaled by the human body can be used for crop growth. According to reports, this method has been used to circulate water in the space station for over hundreds. of days.