How to guide parents to carry out small science experiments at home
Today, 18 scientific experiment is introduced. Awesome!
1, discolored flower
Material preparation: two light-colored flowers with stems, two identical transparent bottles and blue ink.
Experimental operation:
(1) Fill two transparent bottles with the same amount of water, and drop a few drops of blue ink into one bottle.
(2) Put the two flowers in a transparent bottle respectively, and observe the color changes of the flowers after a few days.
Guiding suggestions:
● The color of flowers provided to children should be as light as possible.
● Pay attention to guide children to observe the changes of stems and flowers every day and make records.
Expand substitution: You can do experiments with easily observed plants such as celery and coriander in natural corners to guide children to observe and record.
Attachment: Little scientific knowledge.
Stem is one of the vegetative organs of plants, which has the functions of supporting plants, transporting water and nourishing food. The stems of plants can transport water and nutrients absorbed by roots to all parts of plants from bottom to top. The flowers in the vase will change color precisely because the stems have blue ink.
2. balloons that ignore each other
Material preparation: two balloons, dry flannel (or sweater) and thin thread.
Production method: blow two balloons filled with air, tie them to prevent air leakage, and connect them with thin iron wires.
Experimental operation:
(1) Let the children hold the middle of the thin line, and they will find that the two balloons are close together.
(2) Let the children fully rub the two balloons with dry flannel (down jacket), and then lift the thread, and you will see that the two balloons are separated.
Guidance and Suggestions: Remind children to use moderate force when rubbing, and don't break the balloon.
Extended substitution: Tie the plastic rope into a handle and keep stroking it from top to bottom, and you will see the plastic rope unfold like a flower.
Attachment: Little scientific knowledge.
Scientific experiments show that the electricity brought by friction is either positive or negative. The same electricity as the glass rod wiping wire is called positive electricity; The charge that is the same as that of rubber rod rubbing fur is called negative charge. The same charges repel each other and different charges attract each other. Because two balloons are rubbed by flannel and have the same charge, they will repel each other and naturally separate.
3. Battery series
Material preparation: battery family diagram of various batteries and electric toys.
Experimental operation:
(1) Let children observe the appearance characteristics of batteries and sort or queue them according to their models and functions.
(2) Guide children to choose suitable batteries and put them into electric toys in the right way to make them move.
Guiding suggestions:
● Guide small class children to understand the role of batteries in the process of playing electric toys.
On the basis of understanding the battery, guide the middle and large class children to install the battery for toys, and guide the children to observe the "0" and "1" poles of the battery and install them correctly.
● Remind children to recycle used batteries to designated places.
Extension and substitution:
◆ Guide children to find things that need batteries at home with their parents in daily life, such as mobile phones, flashlights, clocks and watches. , and try to remove the battery.
Conditional kindergartens can provide children with various rechargeable batteries, so that children can understand the difference between rechargeable batteries and ordinary batteries.
Attachment: Little scientific knowledge.
A battery is a small device that can generate electricity, such as a solar cell. The chemical batteries we usually use can be divided into primary batteries and secondary batteries. The primary battery can generate current after it is made, but it is discarded after it is discharged. Battery, also known as secondary battery, can be discharged after charging and reused after discharging. At present, our general disposable batteries mainly include carbon batteries and alkaline batteries. Generally, each battery is 1.5V and cylindrical. Common models are 1, 5, 7. The larger the number, the smaller the model. When we correctly install the battery into the electric toy and turn on the switch, the battery can provide current for the circuit, and at the same time, the toy can move by converting electrical energy into mechanical energy.
4. Magnetic field lines
Material preparation: a small dish and a plastic bag; A piece of handmade paper, some iron filings; Bar magnet.
Experimental operation:
1. Put the magnet in a plastic bag, then stir it in the sand, then take out the plastic bag and put it on a small plate. Take out the magnet, and the iron filings will fall. After many times, you can get a lot of iron filings.
2. Put the magnet on the handmade paper, scatter the collected iron filings evenly around, and gently pat the handmade paper. Due to the magnetic field, the pattern of magnetic field lines will appear on the paper.
Guiding points: educate children not to put magnets near electronic products such as mobile phones, watches and televisions to avoid damaging these electronic products.
5. Beautiful rainbow
Material preparation: two plastic water bottles and a compass; An awl, some water; A small sewing needle.
Experimental operation:
1. Punch about 20 holes in the plastic bottle cap with a sewing needle, fill the plastic bottle with water, cover the bottle cap tightly, hold the bottle with your back to the sun, and gently squeeze it to make the water spray out, and you can see the rainbow.
2. Punch another bottle cap with an awl and repeat the above experiment. This time, you can't see the rainbow in the light rain from the bottle cap.
Guiding points: to guide children to pay attention to the use of sewing needles when piercing with sewing needles, and be careful not to hold them in their hands when using sewing needles.
6.water flute
Material preparation: a long straw and a pair of scissors; Glass bottle; A bottle of water.
Experimental operation:
1, with an empty glass bottle, put half a bottle of water in the bottle;
2. Cut a hole in about one third of the long straw with scissors, so that it is almost broken, but still connected to one point;
3. Bend the straw at the cut, and insert a long straw into the water with the cut on the water surface. Blow hard into the straw and you will hear the sound. Adjust the position of the straw in the water and the sound will change again.
Attachment: Little scientific knowledge.
When we blow into the straw, there will be an air jet. When this transverse airflow passes through the nozzle of a long straw, it causes the vibration of the air column in the straw, thus producing a weak but stable sound. When a long straw falls in the water, the vibrating air column is shortened, resulting in a high pitch. When the straw rises, the air column is elongated, producing a low-key sound.
7, homemade gyro
Material preparation: waste CDs, watercolor pens and post-it notes of various colors.
Production method: Decorate the CD with various post-it notes, and then insert a watercolor pen with moderate thickness through the small hole on the CD and fix it.
Experimental operation: let the children twist the gyro hard, then let go and let the gyro rotate to see who rotates the gyro for the longest time.
Guiding suggestions:
● Instruct children to observe the difference of rotation speed and time with the two ends of watercolor pens as fulcrums respectively.
● Observe the color change of post-it notes on the CD when the gyro rotates at different speeds.
● Adjust the distance between the fulcrum and the ground, and observe the change of gyro rotation time.
● Instruct children to rotate the gyro with different strength and observe the rotation time of the gyro.
Extension and substitution:
◆ Gyroscope can be made of cardboard, matchsticks or other materials.
◆ Decorate the gyro with any two colors of red, yellow and blue, and conduct three-color experiments.
◆ Let children play with various gyroscopes in their lives.
Attachment: Little scientific knowledge.
Gyro is an ancient children's toy in China. It is a rotating body that rotates on the ground. When the gyro rotates, it not only rotates around its own axis, but also makes a conical motion around a vertical axis. In order to make the gyro stand up, external force must be constantly applied. Once the external force is lost, the gyro will soon fall down, because the branches of the gyro are too small to support its own weight. The rotation time of the gyro is related to the distance between the fulcrum and the ground, the force during rotation, the contact area between the fulcrum and the ground and friction.
8, homemade hourglass
Material preparation: several pairs of the same mineral water bottles (different bottle mouths), sand and stopwatch.
Production method:
(1) Two identical mineral water bottles are a group, and a proper amount of sand is filled in one of the mineral water bottles. The amount of sand in each group of bottles remains the same.
(2) Fasten the bottle mouths of each group of mineral water bottles with transparent tape, so that the bottles can be decorated simply and the hourglass is finished.
Experimental operation:
(1) Ask the children to reverse a set of hourglasses, observe the flow of sand and record the time when the sand flows out.
(2) Ask children to reverse several hourglasses of different sizes at the same time and compare the different time when they run out.
Or:
(1) When making an hourglass, the teacher poked holes in the bottle cap with scissors. There are big and small holes, and there can be two or three holes. (See "Homemade Hourglass Diagram 1")
(2) At the same time, in the process of pouring the hourglass, please observe and compare the relationship between the eye size of the bottle cap and the sand flow rate.
Teachers' guidance suggestions:
● Check the hourglass regularly to avoid sand leakage from the hourglass.
● Children can choose their own hourglass competition to see whose hourglass sand flows fast, and remind them to reverse the hourglass to ensure the accuracy of the experimental effect.
● Pay attention to guide children to observe the velocity of sand and record the observation results.
● Collect information to introduce the history of the hourglass to children and know that the hourglass is an ancient timing tool.
Extension and substitution:
◆ Put the millet, mung bean or soybean into the hourglass to make the rice leak.
◆ Let children leak rice reversely at the same time, and observe the flow speed of rice grains at different bottle mouths.
Attachment: Little scientific knowledge.
Give sand an external force and it will flow. Constantly turning the hourglass is equivalent to giving sand an external force, and the sand can flow. The velocity of sand is related to the size of the hourglass bottle mouth, the number and diameter of bottle cap eyes: the larger the bottle mouth, the more bottle cap eyes, the larger the diameter and the faster the velocity; The smaller the bottle mouth, the fewer the bottle cap eyes, the smaller the diameter and the slower the flow rate.
The hourglass, also known as the sand clock, is a device for measuring time. The hourglass consists of two identical bottles connected by a narrow connecting tube. The fine sand from the upper bottle slowly flows into the lower bottle through the middle tubule. The time required for this process can be used to measure time. Once all the sand flows into the bottle at the bottom, the hourglass can measure the time backwards. The advantage of this hourglass is that it can be used on both sides. When turned over, the bottom can be used as the upper part.
9, homemade fountain
Material preparation: two large empty beverage bottles (such as Sprite bottles), tacks and water.
Production method:
(1) Pinch several small holes with the same diameter vertically on one side of a sprite bottle.
(2) Punch several small holes with different diameters on the bottle cap of another Sprite bottle.
Experimental operation:
(1) Let the children fill the first bottle with water, and the water will come out from the small hole in the bottle body, and the water will come out at different distances.
(2) Let the children fill the second bottle with water, tighten the bottle cap, and then squeeze the bottle body hard, so that water will gush out from it like a fountain.
Guiding suggestions:
● When operating the first bottle, teachers should pay attention to guiding children to observe which small hole sprays water far and which small hole sprays water near, and ask children to record their own observation results.
● When operating the second bottle, the teacher should guide the children to feel the influence of force on the size of the fountain.
Extended substitution: Conditional kindergartens can lead children to observe outdoor fountains.
Attachment: Little scientific knowledge.
The pressure of water is determined by the depth of water. The deeper the water, the greater the water pressure. The shallower the water, the smaller the water pressure. Therefore, when the hole diameter L on the bottle body is the same, the water sprayed from the bottom of the bottle is the farthest and the water sprayed from the top is the shortest. In addition, when the bottle body is forcibly squeezed, the water in the bottle is simultaneously subjected to pressure and ejected from small holes with different sizes. The harder you squeeze, the bigger the water pressure and the bigger the fountain.
10, homemade bubble water
Material preparation: washing powder, meal washing, soap flakes, small spoon, water and cups.
Experimental operation: let children choose any material and put it into a cup to make bubble water, and blow bubbles to play.
Guiding suggestions:
● Remind children to make bubble water with various materials to see which materials dissolve quickly and which materials are easy to blow out bubbles. The combination of materials and water blows out bubbles in a large proportion.
● Take children outdoors to blow bubbles and guide them to observe the color changes on the surface of bubbles.
● Remind children not to suck bubble water into their mouths.
Extension and substitution:
◆ When children make their own bubble water, they can provide materials such as salt and sugar that can't blow bubbles, and guide children to conduct comparative experiments.
◆ Let children pay attention to whether bubbles are generated when washing hands, washing faces and brushing teeth.
Attachment: Little scientific knowledge.
Bubbles are formed by the surface tension of water. Usually, the mutual attraction between water molecules is stronger than that between water molecules and air. These water molecules seem to stick together, but if the water molecules stick together too much, it is not easy to form bubbles. Washing powder "breaks" this surface tension of water, which reduces the surface tension under normal conditions to only 1/3, which is the best tension needed for blowing bubbles.
The proportion of bubble water will affect the effect of blowing bubbles. Generally, it is enough to wash 2 meals with bubble water and add 6 parts of water. Glycerol is a hygroscopic liquid. When it is combined with water, it will form a very weak chemical adhesive, which will slow down the evaporation rate of water. Therefore, in order to make bubbles not disappear so quickly, you can put some glycerin in the bubble water. Usually, the best formula of foaming liquid is: 2 parts of clean meal, 6 parts of water, 1-4 parts of glycerol. We can see colorful light through bubbles because light will be refracted when it passes through the film of soap bubbles.
1 1, interesting tumbler.
Material preparation: plastic table tennis, plasticine, colored paper, watercolor pen, sand and mung bean.
Production method:
(1) Cut a small hole in the plastic table tennis ball and stick plasticine in the middle of the bottom of the ball as the body of the tumbler.
(2) Make a cone with colored paper and draw the five senses as the head of the tumbler.
(3) Glue the cone and the plastic ball together with an adhesive to make a tumbler.
Experimental operation:
(1) Let the children push the tumbler with their hands and observe its shaking state to see if it will fall down.
(2) Distribute table tennis to children, let them change the weight of plasticine and its position in table tennis, observe whether the tumbler will fall down, and let them understand that the lower the center of gravity of the tumbler, the more stable and balanced the tumbler will stand.
(3) Let the children fill the table tennis with sand, beans and other materials, then push the tumbler and observe its changes, so that they can understand that the tumbler will not fall down only if the object is fixed.
Guiding suggestions:
● Guide children to push the tumbler with different forces and observe its swing.
● Guide children to observe the shape and internal structure of the tumbler, and understand the characteristics of the tumbler, which is light on the top and heavy on the bottom and round at the bottom.
● Encourage children to find ways to fix the sand and beans in table tennis at the bottom of table tennis.
Extension and substitution:
◆ You can use spherical objects such as egg shells instead of table tennis to make tumblers.
◆ You can also fold the circular cardboard into a semicircle to make a tumbler.
◆ Guide children to find items or toys with the same principle as flat glasses, such as rocking chairs and rocking wooden horses.
Attachment: Little scientific knowledge.
Plastic table tennis has the heaviest plasticine, so it becomes the center of gravity of the tumbler. The lower the sticking position, the lower and more stable the center of gravity of the tumbler. When the tumbler is in equilibrium, the distance between the center of gravity and the contact point is the shortest, that is, the center of gravity is the lowest, and it is the most stable at this time. When pushing the tumbler, the contact point between the tumbler and the desktop is not in a straight line with the center of gravity. After the external force is removed, gravity will make it return to the lowest center of gravity to maintain balance, so the tumbler will not fall down no matter how it is shaken.
12, shadow formation
Material preparation: flashlight, small doll (opaque object), glass (transparent object), plastic cup (translucent object), recording paper and pen.
Experimental operation:
(1) Put three kinds of objects on the floor and let the children shine with a flashlight to observe and record their shadows.
(2) Change the position of the flashlight, illuminate the small doll (opaque object), and observe and record the shadow formed by the doll.
(3) Keep the flashlight still, change the distance between the doll and the flashlight, and observe the change of its shadow size.
Guiding suggestions:
● In order to obtain satisfactory activity effect, it is best to cover the windows of the activity classroom with opaque curtains.
● Guide children to analyze the causes of shadow formation and the influence of light source position on shadow.
Extension and substitution:
Conditional kindergartens can provide projectors, emergency lights and spotlights for children to play games.
◆ Observe the shadows of objects at night and look for light sources.
Choose an object outdoors, and let the children draw the changes of the shadow of the object during the day, and measure and record it.
Attachment: Little scientific knowledge.
If the light is blocked by an opaque object when traveling in a straight line, it will form a shadow on the back of the object. Light can completely penetrate transparent objects, so completely transparent objects cannot form shadows; When light passes through a translucent object, it will give off some light and form a semi-transparent shadow. The shape and size of the shadow will be different with different angles of light irradiation. The size of the shadow varies with the distance between the object and the light source.
13, hedgehogs have long thorns.
Material preparation: magnet, scrap iron, rectangular plastic tray, white paper and crayons with the same size as the bottom of the tray.
Production method:
(1) Draw a little hedgehog squatting under the apple tree on the paper, and pay attention to the thorns on the hedgehog.
(2) Spread the picture on the tray.
Experimental operation: Sprinkle the iron filings on the painting gently, then put the magnet under the support box, and move the magnet gently to suck all the iron filings from the hedgehog to help the hedgehog grow spikes.
Guiding suggestions:
● Remind children to be careful when taking and putting iron filings, and be careful not to scatter iron filings outside the tray, and don't blow on iron filings to prevent eye-catching.
● The size of the magnet provided to the child should be the same as the size of the hedgehog painted, so that the performance effect is more vivid.
● Move the magnet under the tray at will to observe the movement state of iron filings.
Extension and substitution:
◆ Change the background picture at will, and carry out interesting modeling activities with iron filings.
◆ Show the distribution of magnetic field lines of strip and U-shaped magnets with iron filings, and feel the existence of magnet magnetic field.
Attachment: Little scientific knowledge.
Magnets can attract iron objects, and the fine shape of iron filings can show unique artistic modeling under the attraction of magnets. Iron filings can also show the presence of magnetic fields of magnets. Using the effect of iron filings on magnetic field lines, children can visually perceive the distribution of magnetic field lines of magnets with different shapes.
14, water absorption experiment
Material preparation: newspaper, electro-optic paper, paper towel, kraft paper, dropper, washbasin, ruler and adhesive tape.
Experimental operation:
(1) Cut newspapers, electro-optic paper, paper towels and kraft paper into strips with the same size, and then stick one end on a ruler with adhesive tape to make the hanging paper strips have the same length. Hold a ruler in your hand and put it above the water. At the same time, let the note be immersed in the water, and let the children observe which note's water rises quickly, indicating that it has strong water absorption ability.
(2) Spread four different kinds of paper on the table, and drop the same amount of water drops on each paper at the same time to see which paper the water drops spread fastest.
Guiding suggestions:
● Before the activity, teachers should observe different kinds of paper with their children to understand their characteristics.
● The selected paper has different textures, so that children can see obvious experimental effects.
In order to ensure the scientific nature of the experiment, it is necessary to operate these four kinds of paper at the same time.
Extension and substitution:
In addition to all kinds of paper, teachers can also provide other materials, such as sponges, towels, cloth and so on. Conduct a comparative experiment. (In order to make the effect observed in the experiment more obvious, it is suggested to use the same size materials. )
Attachment: Little scientific knowledge.
There are many tiny holes in the plant fiber of paper, and the fiber's attraction to water is greater than that between water molecules, so that it can attract and retain water molecules under the action of gravity, which is the so-called water absorption of paper. Because the pore size and quantity of plant fibers in different papers are different, their water absorption strength is also different.
15, magic papermaking
Material preparation: waste paper, water, glue, rubber gloves, plastic plates, gauze and sticks.
Production method:
(1) Soak the waste paper and chop it up, the smaller the better, and then soak it in proper amount of water.
(2) Let the children put on rubber gloves to grab the soaked paper, add glue and stir it evenly with a wooden stick.
(3) Dehydrate the prepared paper pulp on gauze, and then spread it evenly on a plastic board to flatten and dry.
Experimental operation: Let children feel the fun of making paper, and write and draw on the dried paper.
Guiding suggestions:
● Remind children to tear thinner paper by hand as much as possible, and don't use machines, so as not to damage the plant fibers of the paper, and the more broken it is, the better.
If there is too much water after the paper is soaked, remind the child to filter out the excess water before adding glue.
● When drying pulp, remind children that the thinner the sun, the more uniform it is.
Extended substitution: thicker pulp can be made into thicker cardboard, or pressed into various shapes with some molds, such as masks.
Attachment: Little scientific knowledge.
Paper is a sheet fiber product used for writing, printing, painting or packaging. Generally, it is made from the aqueous suspension of plant fibers through pulping, staggered combination on gauze, preliminary dehydration, compression and drying. China was the first country in the world to invent paper. A long time ago,' our ancestors carved characters on tortoise shell bones and later wrote on bamboo slips', but these things were heavy. Later, it was also written on silk. Although it is light, it is expensive. About 2,000 years ago, Cai Lun in the Eastern Han Dynasty invented paper made of common or discarded materials such as bark and rags, which was very suitable for writing and slowly spread all over the world.
16, magic magnifying glass
Material preparation: magnifying glass, flat mirror, various objects or specimens, black paper, white paper and scissors.
Experimental operation:
(1) Let children observe various objects or specimens with a magnifying glass.
(2) Guide children to observe and compare the differences of the same object under a flat mirror and a magnifying glass.
(3) Guide children to ignite with a magnifying glass: when the weather is fine, take a piece of paper, then put the magnifying glass in the sun and focus on the paper. After a while, the paper will ignite.
(4) Guide children to play chicken flipping: take a piece of black paper, cut it into the mirror size of a magnifying glass, cut a hollow chicken in the middle of the paper, and then stick the paper on the magnifying glass. Then aim the magnifying glass at the sunlight and put a piece of white paper on the back of the magnifying glass. When the magnifying glass is close to the white paper, you will see the chicken standing on the paper. When the magnifying glass is far away from the white paper, you will see the chicken turn over on the paper.
Guiding suggestions:
● Teach children how to use a magnifying glass.
● Guide children to constantly change the distance between the object and the magnifying glass and observe the changes in imaging in the mirror.
● When playing a game lit with a magnifying glass, remind children to pay attention to safety.
Expand substitution: let children observe which items in life use the principle of magnifying glass.
Attachment: Little scientific knowledge.
Magnifier is a lens made of transparent material, the central part is thicker than the edge part, which can make the light converge.
Magnifier focuses light by refraction, which raises the temperature of the focused object and gradually reaches the ignition point. The larger the diameter of the magnifying glass, the higher the focusing temperature; The smaller the diameter, the lower the focal temperature.
The distance from the optical center of the lens to the focusing point is called the focal length. The object becomes an upright magnified virtual image within a focal length of the magnifying glass; The object becomes an inverted magnified real image when the focal length is greater than 1 times and less than 2 times; The object becomes an inverted real image with twice the focal length; An object becomes an inverted, reduced real image at more than twice the focal length.
17, melting and dissolving
Material preparation: several small bowls of the same size, thermometer, candy, coffee, sugar, salt, spoon, cup and drinking water.
Experimental operation:
(1) Put several small bowls filled with water of the same size into the refrigerator and freeze the water into ice cubes. If it is winter, it can be naturally frozen outdoors.
(2) Take out several ice cubes at the same time, guide children to melt ice cubes in various ways, and compare different melting speeds. For example, let it melt naturally indoors, heat it, and let it melt in the sun.
(3) Let the children scoop a spoonful of coffee, a spoonful of sugar, a spoonful of salt and a lollipop, and then put them into cups with different temperatures but the same amount of water at the same time, stir them with a spoon and observe the dissolution phenomenon.
(4) After dissolution, please ask children to taste it, which will have a sweet, salty and bitter taste to help children feel the dissolution phenomenon further.
Guiding suggestions:
● When observing the melting phenomenon, pay attention to let children compare the influence of temperature on ice melting.
● When observing the dissolution phenomenon, let children observe and compare which objects are easy to dissolve and which objects are not easy to dissolve, and let children compare the effects of different water temperatures and mixing speeds on dissolution.
● Instruct children in large classes to learn to use thermometers, and let them try to record their observed results and temperatures.
Extension and substitution:
◆ Children are advised to add ice cubes to drinks to make delicious cold drinks.
◆ When children make their own cold drinks, guide them to observe the relationship between ice cubes and water temperature: as the ice cubes melt, the drinks gradually get cold, and the more ice cubes, the lower the water temperature.
◆ Encourage children to choose a variety of materials to make their own drinks at home, such as milk powder, coffee and orange powder. To further feel the dissolution phenomenon.
Attachment: Little scientific knowledge.
The process of changing a solid into a liquid by heating is called melting. Usually, the higher the temperature, the faster the ice with the same volume will melt. The process that one substance (solute) disperses in another substance (solvent) and becomes a solution is called dissolution. For example, salt or sucrose dissolves hand water and saline solution. The speed of dissolution is related to the nature of solute, the stirring speed of solute in solvent and the temperature of solvent. Generally, granular solutes are more soluble than bulk solutes; The solute in stirred solution is easier to dissolve than that in non-stirred solution. High-temperature solvents are more soluble than low-temperature solvents.
18, a small capsule that can somersault.
Material preparation: 3 empty capsules, L steel balls, some small grains of sand, L cotton, L cardboard and some building blocks.
Production method:
(1) Put the steel ball, sand and cotton into three empty capsules respectively.
(2) Stack several building blocks, fold both sides of the cardboard to make a track, and put one end of it on the building blocks to form a certain slope.
Experimental operation:
1, put the capsule with steel balls on the inclined cardboard, and you will see that the capsule has been turned up and down.
2. The other two capsules are also placed on the cardboard to see if they will roll.
Guiding suggestions:
1, the speed of capsules filled with steel balls will be different when children observe the inclination angle of cardboard.
2. Children observe and compare the movements of capsules made of different materials.
Extension and substitution:
◆ Find a rectangular object similar to a capsule to do experiments instead of capsules.
◆ Find other materials that can roll instead of steel balls, so that the capsule can turn over.
◆ Put the capsules filled with steel balls into the carton, tilt the carton at will, and observe the rotation direction of the capsules.
Attachment: Little scientific knowledge.
When the capsule with the steel ball is placed on the inclined plane, the steel ball rolls under the action of gravity, which drives the capsule to slide down and changes the center of gravity of the capsule. In the process of continuous descent, the center of gravity of the capsule is constantly changing and will keep rolling. However, sand, cotton and other substances do not have the property of rolling on the inclined plane, so the center of gravity of the capsule cannot be changed and the capsule cannot roll.