scientific invention

Wool doll

Colorful wool dolls are beautiful and lovely, because your skillful hands and love endow them with beautiful images, and they will also become your best friends.

1. Materials and tools: all kinds of wool, cotton or elastic wadding, silk flower petals, all kinds of post-it notes, buttons, ribbons, double-sided tapes and scissors.

2. Take the emperor for example? Hey? What happened? Huan? Hey? Hey? Duh? Coin color cutting? Ant fold? BR>3. The wool bundle is folded in half at the tight place, and the two sides are slowly unfolded, and a small ball of cotton is wrapped inside.

4. After confirming that the cotton is completely wrapped by wool, tie the lower part with a ribbon (stick the ribbon with double-sided tape), and the doll's head and body will be separated.

5. Take a short piece of wool and tie it tightly at both ends. This is a doll's hand.

6. Separate the body of the wool doll from the middle and put it in the doll's hand.

7. After you close your body again, tie the lower part of your hand with a ribbon.

8. Braid with wool. Of course, no matter what hairstyle and color you like, you can be like her.

9. Tie the braid in the middle of the doll's head with a messenger wire.

10. Thread silk flower's petals and a button through the hanging line in turn to cover the doll's head. That's her hat.

1 1. Cut out the eyes and mouth on the post-it note and stick it on the doll's face.

12. This is the finished wool doll. They can be hung on your bedside or desk lamp or schoolbag to accompany you every day.

Measure how much rain it rained today

It is raining again. Looking at the rain scene outside the window, do you suddenly want to know how much rainfall there is in farmland, rivers and streets? When listening to the weather forecast, I often hear: "According to the measurement of a weather station, what is the rainfall today ... So, what is rainfall? How is rainfall measured?

Rain falls from the sky to the ground without evaporation, infiltration and loss. The depth of water layer accumulated on the horizontal plane is called rainfall (mm), which can directly indicate the amount of rainfall. At present, the instruments commonly used in meteorological stations (stations) to measure rainfall are rainfall cylinders and measuring cups. The diameter of the rain tube is generally 20 cm, and it is equipped with a funnel and a bottle. The diameter of the measuring cup is 4 cm. Pour the rainwater in the rainfall pipe into the measuring cup, and you can know the rainfall of the day according to the scale on the cup.

Don't worry if you don't have a rain cone at hand. You can make one by yourself with some commonly used utensils, and the effect is quite good. Take a porcelain bowl with a diameter of 20 cm, drill a hole slightly larger than corn kernels at the bottom, and then put the porcelain bowl on an uncovered jar (there is a glass bottle in the jar, and the bottle mouth is connected with the hole at the bottom of the bowl). In this way, the simple rain pipe is completed. After the simple rain pipe is completed, it can be placed at a height of 70 cm from the ground to receive rainwater. After the rain stops, weigh the water in the bottle with a scale. 30 grams of water is equivalent to 1 mm of rainfall.

Rain from the sky is a very important water source on land. If it is not polluted, its water quality can almost be comparable to distilled water. At present, rainwater collectors have been installed in some places. With a little treatment, the collected rainwater can be used to water green spaces, clean vehicles and wash roads. Do you have your own ideas on how to make full use of falling into the water?

A horn that can "breathe" the flame

Take a can, cut off all the open ends of the can, and open a small hole about 2cm from the bottom of the can. Then take a piece of hard paper (or dung paper) and roll it into a trumpet shape, put the mouthpiece of the trumpet into the small hole of the can, and fix the joint firmly with Black & Decker glue to avoid air leakage, because this is related to the success or failure of the experiment (scrape the edge of the small hole on the can with a knife several times to make its surface rough and sticky). & ltBR & gt& ltBR & gt experiment (1): light the candle, put the flame near the bell mouth, and quickly press the can into the container filled with water. It can be seen that the flame of the candle deviates outward, as if it were spit out from the bell mouth (Figure 1). & ltBR & gt& ltBR & gt Experiment (2): Press the can slowly into the water to a certain depth, and then pull it up quickly, and you will see the tenon of the trumpet swallowing the candle flame. BR>& ltBR & gt Its physical principle is that the pressure of a certain amount of gas is inversely proportional to its volume under the condition of constant temperature. The gas in the tank is compressed, and when it drops rapidly, the pressure increases. When the pressure is higher than the outside air pressure, the gas in the tank will be blown out of the horn and the flame will deviate outward. On the contrary, pull it up quickly, the internal air pressure is less than atmospheric pressure, and the candle is swallowed into the horn.

coccinella septempunctata

Raw materials: spherical medicine box with Chinese patent medicine; Red and black watercolor pens or pigments can be used; A pin.

1. Wash the medicine box, remove the smell of the medicine, dry it, and take half for later use;

2. Use a red watercolor pen or red pigment and pigment to evenly smear half a medicine box;

3. Put half of the color medicine boxes under the fan to dry. Draw a dot on the red background with a black watercolor pen or black pigment, draw a semicircle on one edge as the head (see the diagram for details), and draw a slightly thick black line in the middle of the medicine box with this semicircle as the starting point;

4. Insert two pins on both sides of the head as the head whiskers of the ladybug. In this way, a lovely ladybug is ready.

Double cone capable of rolling upwards

1. material: thick paper cut into a circle (the diameter should be within 15cm), scissors, glue, a pair of chopsticks or two long thin sticks, a big book and a small book.

2. Cut the round thick paper in half, roll it into two cones with the center of the circle as the vertex, and stick it firmly with glue.

3. Glue the bottoms of the two cones together to form a double cone.

4. Put a big book and a small book on the table, with the back facing up and a certain distance apart. Put two chopsticks or thin sticks on the book, so that the higher end is slightly separated from the lower end. At this time, you put the bipyramid at the end of the chopsticks near the book, and you will be surprised to find that it will roll uphill along the track!

Its principle is:

The center of gravity of the bipyramid is at the intersection of the connecting line between the two ends and the center of the middle circle. Because chopsticks are open, if you carefully observe the two ends of the double cone, they actually roll down. On the surface, the end of the bipyramid is higher than the starting point, but its center of gravity keeps going down. Remember, unless there is an external force, gravity will always make objects move toward the center of the earth, so don't confuse them.

Balance for weighing air

Making materials: paper, glue, candle, thin thread.

Production steps:

1. First cut two pieces of paper, 34cm long and15cm wide. Each piece is divided into five parts according to the drawing, of which the narrow part on the right is 2 cm wide and the other four parts are equally divided.

2. Fold the paper strip into a square barrel shape according to the parting line, and the narrow part with a width of 2 cm is used as the adhesive tape.

4. Press into the middle ends of the two sides of the upper part of the square barrel and stick it on, with a thin line 20 cm long in the middle. The lower half is still supported into a square barrel according to the folding line. This is the weighing bag of the balance.

5. Cut a piece of paper 25 cm long and roll it into a thin stick, which is the weighing rod of the balance.

6. Tie two weighing bags to both sides of the weighing beam, tie a thin line in the middle of the weighing beam, and carefully adjust the balance.

7. Put the burning candle under a weighing bag (be careful not to burn the weighing bag), and the weighing bag will start to rise immediately. While the other weighing bag begins to descend. This shows that warm air is lighter than cold air! Why? Because the relative density of hot air is smaller than that of cold air, it is lighter than cold air, and hot air balloons are made according to this principle.

"Little pig" who can run

In my spare time, it's interesting to be a "running pig" by myself.

Material L: cardboard, yellow mud, rubber band, string, color, paste, scissors.

Methods: ① Draw a pattern as shown in figure 1 on the cardboard, cut it out, punch a hole at "0" and fold it at the dotted line.

② Make a "mud wheel" with yellow mud (preferably plasticine).

③ Insert a single rubber band into the left and right holes of the "mud wheel" and tie rubber bands on both sides for fixation.

(4) Fix a rope on the "mud wheel", wrap the rope around the middle of the wheel several times, and put the end out of the hole in the middle.

When playing, lift the strings from the top first. At this point, the pig's weight will pull the wheel to rotate backwards, and the rubber bands on both sides of the "mud wheel" will tighten in the opposite direction; Then, put the pig made of cardboard on the table and put down the rope. With the power of the rubber band, the small wheel will rotate forward and the "little pig" will automatically run forward.

Self-rotating paper

Prepare a rectangular piece of paper (length 3 cm, width 1 cm) and a long sewing needle.

Fold in half according to the horizontal and vertical midline of the paper. Then unfold the paper, and put the intersection of the two creases on the vertical needle tip (first fix the needle on the cork with the needle tip facing up), so that the needle tip is just opposite this point, and the paper is balanced on the needle tip. Rub the palms together to raise the palm temperature, and then slowly put the palms next to the paper (as shown in the figure below).

Be careful, be gentle with your hands, and don't let the wind blow the paper off when you do it manually. At this time, you can see the paper spinning. Slow at first, get up slowly. If you take your hand away quietly, the paper will stop spinning at once; Move your hand closer and the paper will spin again.

What mysterious force makes paper spin?

It turns out that due to the different temperatures of different parts of the human hand, the temperature of the finger end is always lower than that of the palm; So near the palm of your hand, it will cause a strong updraft, and its force on the paper is also greater than that on the finger end, which can make the paper rotate.

Sponge sheared chicken

By cutting, pasting, dyeing and other ways, a small and exquisite animal work can be created by using the scraps scattered by the sponge according to its shape and the shape of the animal. Let's take making chickens as an example:

I. Production materials

A sponge, watercolor paint, two beads, and black & decker glue.

Second, the production method

1. Cut the sponge into a cuboid and draw the general outline of the chicken's body, head, feet (feet can be larger) and mouth on the cuboid. (Figure 1).

2. Take a good look at the outline (leave some room) and boldly cut its side shape (Figure 2).

3. Trim the head, body and feet in the front and back direction of the chicken, and cut the chicken wings (not too deep). Pay attention to keep the chicken upright when pruning (Figure 3).

4. Starting from the overall shape, carefully trim the parts and remove the scissors.

5. According to your own preferences, you can dye it as a whole or locally. After drying, decorative beads are pasted as eyes (Figure 4). If there are several sponges with different shapes, you can design several nestlings with different postures according to the above method. A group of lively and lovely chickens will make you fondle admiringly.

Mofazhi bridge

1. experimental materials: two cups, some cardboard, a heavy object (such as soap), a paper cutter and a glue stick.

2. Open two cups at both sides and spread a piece of cardboard on them. This is a simple paper bridge.

Try to see how much weight it can bear. As a result, the weight collapsed as soon as it was put down.

4. Fold this paper into corrugated shape every 1cm, and the new bridge deck is completed.

5. Rebuild the paper bridge. You see, this time, the weight is stable.

6. Cut the cardboard into many thin strips and roll them into tubes respectively.

7. Put these cylinders side by side and you will see another kind of bridge deck.

8. This paper bridge is also very strong and has great bearing capacity.

Experimental principle: a flat piece of paper is very thin, and the small stress thickness leads to small bearing capacity. After the paper is folded into a corrugated shape or rolled into a cylindrical shape, the stress thickness is greatly increased and the bearing capacity is much greater. This kind of structure is often used in stressed structures such as bridges and buildings. It is light and strong, and saves a lot of materials compared with solid structures. Think about it, what other structure can achieve this effect?

Egg jet boat

1. experimental materials: eggs, cardboard, thick iron wire, candle head, straw, double-sided tape, scissors and pliers.

2. Cut a piece of cardboard with a length of 25 cm and a width of 15 cm, and draw a folding line according to the pattern to make the hull.

3. Fold the hull according to the folding line.

4. Stick the double-sided adhesive tape on the extra cardboard at both ends of the ship, fold it inward and stick it.

5. Cut a rudder?

6. Cut a vertical seam in the middle of the stern, plug in the rudder, and put two thick iron wires in the boat at a distance of 3 cm, with the middle of the iron wires slightly bent.

7. Stick a small hole in one end of the egg, stick two small holes side by side at the other end, and blow air into the egg from one small hole to let the contents of the egg flow out from the other end.

8. Cut the straw into two pieces (air jet) with a length of 4 cm, insert them into two holes at one end of the egg with a depth of about 1 cm, and then seal them with wax.

9. After pouring water from the other end of the egg (note that the water level should be below the spray pipe), seal the mouth with double-sided tape. This is a small boiler.

10. Now make the stove! Put the candle end on the bottom of the boat (between two iron wires) and light it. You can put a bottle cap under the candle.

1 1. Put the egg cooker on the thick iron wire, and the air jet pipe is horizontally backward. After a while, the water boiled, a steam came out of the jet pipe, and the ship moved forward in the water! If its rudder deflects at a certain angle, the ship will circle in the water.

Experimental principle: The steam generated continuously after water boiling can only be discharged backward from the injection pipe, thus generating a backward force, which has a forward reaction force on the ship, so the ship sails forward. This conforms to Newton's third law. Every action has an equal reaction.

Table tennis doll

1. Let's make another lovely doll. She is also made of those old useless things around us. With imagination and your little hands, ping-pong dolls are your favorite.

Materials and tools: bath balls, all kinds of cardboard, table tennis, wool, fluffy balls, velvet strips, small things that can be used as eyes, double-sided tape, scissors.

2. Cut a hole with a diameter of 1.5cm in the middle of the table tennis.

3. Cut out a trapezoid with a width of 5.5cm at the upper end, a length of10cm at the lower end and a length of 1 1 cm with cardboard, stick double-sided adhesive on one hypotenuse, and bond with the other hypotenuse to form a column, and finally cut the upper and lower ends flat with scissors, which is the doll's body.

4. Cut a small piece of nylon net on the bath ball, wrap it around the post and stick it with double-sided tape.

Insert the upper end of the column into the hole in the table tennis ball, and the doll's head will be connected with the body.

6. Cut a piece of velvet with a length of 10 cm, stick it on the back of your body with double-sided adhesive, and then bend it into a doll's hand.

7. Braid with wool.

8. Stick the braid on the head of the ping-pong doll with double-sided tape, stick two plush balls at the bottom of the column as feet, and stick eyes and mouth on the ping-pong face.

9. Cut a piece of cardboard equivalent to the circumference of table tennis, stick it on the head of the table tennis doll with double-sided tape as a hat, and flatten the upper end with your fingers.

10. Stick a piece of double-sided adhesive on the middle and top of the hat, and stick colored fluffy balls one by one as the decoration of the hat. If you like, you can also cut her a small bow tie with flannel and hang it around her neck. Look, that ping-pong doll is smiling at you.

New year pendant

During the Spring Festival, students may receive a lot of lucky money. Have you ever thought that a New Year's greeting bag with lucky money can also be turned into a beautiful and festive pendant?

1. Materials and tools: 12 new year's packages, 1 Chinese knot, a silk thread (rope), adhesive tape paper and double-sided adhesive tape.

2. First, fold each New Year's bag in half, and then fold the four corners to the middle crease.

3. Stick double-sided tape on the bottom of each corner.

4. Wrap the silk thread around and tie a knot. One end of the tape paper is stuck on it through the silk thread, and the other end is stuck on the inside of a new year's package (near the crease). In this way, the hanging silk thread is fixed, so be careful not to expose the tape paper.

5. Glue four New Year greeting bags with silk thread, fold the corners and fold the corners together, which is the top of the pendant.

6. Take another folded New Year's bag and stick the Chinese knot in it like a silk thread. Then four new year's packages, including it, are glued together at the corner, which is the bottom of the pendant.

7. Now there are 8 folding corners at the top and bottom of the pendant, so stick the remaining 4 New Year's bags in the middle.

8. After the bottom and top are connected with four New Year bags, the pendant is finished. Does it look nice?

A roaring little box

Experimental materials: a paper (wood or iron) box, a pencil, a rope, a piece of rosin, colored pencils, glue and white paper.

Second, tie the rope in the middle of the pencil.

Third, rub the rope with rosin, just like rubbing the bowstring of an instrument, making it astringent.

Fourth, open the box and propose a toast? Wish? ρ persimmon fierce? BR>5. Wrap the white paper outside the box and stick it with glue.

6. Draw a lion or other loud guy on the box, with its tail just aimed at the exit of the rope.

Seven, hold the box with one hand, and draw the rope with the index finger and thumb of the other hand. Ah, you heard the roar of the lion ... Experimental principle:

After the friction of the rope reaches the box, its four walls will vibrate and make a noise. Using boxes of different shapes and materials to do this experiment will make different sounds, and sometimes the noise will be staggering. This principle is used to sound stringed instruments, such as violin and cello.

Rubber band guzheng

1. Materials and tools: an empty wooden box or cardboard box, a piece of plywood or stronger cardboard, several rubber bands and scissors.

2. Cut the plywood or cardboard into a right triangle, and cut a small gap on the hypotenuse every 1 to 2 cm.

3. Stick the cut right triangle in the middle of the empty wooden box and stretch the rubber band on the gap between the box and the inclined plane.

4. Try pulling the rubber band. Can you play 1-2-3-4-5-6-7? ... Adjust the elastic band to adjust the scale.

Auspicious pendant

The new semester began, and the students got together. In your spare time, try to make some small pendants for yourself, or give them to teachers and classmates with a sincere blessing.

1. Materials and tools: golden paper (which can also be replaced by other colored paper), Chinese knots, KT blow-molded board (which can also be replaced by colored cardboard), thin strips of wood, thin thread, double-sided adhesive tape, paper cutter and scissors.

periscope

Students, if you can have a periscope, you can see things in the distance clearly, such as being blocked by tall people, just like a submarine can observe the situation on the sea under water. Interesting, isn't it? Let's make one now.

1. Preparation materials: cardboard, small mirrors with two sides 10× 7.5cm, scissors, double-sided tape, triangular ruler, knife and pencil.

2. Cut the thick card red into 3 1×40 cm, and draw a line on the cardboard, as shown in the figure. The four parallel lines are separated by 7.5 cm, the square marked with "×" on the left is 7.5×7.5 cm, the square in the lower right corner is the same size, and a circle with a diameter of 4 cm is drawn in the middle.

3. Cut the square marked with "×" and the circle in the lower right corner, fold the four parallel lines inward respectively, and stick double-sided tape on the outermost narrow edge of 1cm to stick the cardboard into a cylinder. The square and circle that have just been cut off form two small windows with opposite directions.

4. Take out the glass in the small mirror and stick double-sided tape on all sides.

5. Stick two pieces of glass on the inside of a long cylinder at an angle of 45 degrees with the window, and pay attention to the position of the two pieces of glass after sticking. Please note that windows and columns should not be blocked.

6. Stick the cut square on the top of the long column with double-sided tape, and the small periscope is completed. You can see many unexpected things with it. Experimental principle: Because the light is reflected twice by the mirror and transmitted in the periscope body (long cylinder), your sight can be extended as long as your periscope body is made.

Write in invisible ink

In adventure novels, you can often read secret letters or treasure maps written in "invisible" ink ... how the protagonist in the book goes through all the hardships to expose the secrets. Today we are going to learn how to write this top secret letter. ...

1. Plain white paper, pen, lemon.

2. Cut a lemon in half, and this is your "invisible" ink.

3. Press the pen hard into the lemon pulp to make the nib penetrate into the lemon juice. But not too much, or it will drip.

Write your "top secret letter" on the paper with this special ink. Use some force when writing to make the strokes thicker. Words written with a thick nib work best.

The lemon juice is almost dry, so you can't read your handwriting.

6. Bake the written paper slowly with a lighter. Be careful not to burn the paper, or what you wrote will disappear forever! In the process of heating, the invisible handwriting gradually becomes brown, and the letter can be read!

Small telephone

1. experimental materials and tools: 2 paper cups (or empty cans), a long rope, colored paper, scissors, double-sided tape, and small round beads that can be used as eyes.

2. The two microphones of the small phone are cute cartoon friends. Let's keep them alive first. First, cut off the "parts" of a small frog with green paper-forelimbs, hind legs, eyes, etc.

Stick these parts on a paper cup and make a little frog.

You can also make a puppy or any small animal you like in this way and paste it on another paper cup.

5. Make a small hole in the center of the bottom of two paper cups (now cartoon microphones).

6. Thread both ends of a long rope (the length should be greater than10m) into the small hole at the bottom of the cup, and then tie a big knot.

7. After the small phone is finished, put one microphone of the small phone to your ear, and then ask your friend to stand at a distance of 10 meter with another microphone (if the length of the rope exceeds 10 meter, stand at a distance of 10 meter. That is, the length of the rope is the distance between the two), singing or talking into the microphone. The rope should be tight and you can't touch anything else.

8. Although the distance between you and your friend is 10 meter, you can hear his voice clearly. Experimental principle: The sound of your friend singing and talking will make the bottom of the paper cup (microphone) vibrate, and the vibration will be transmitted to the paper cup in your ear along the rope, causing vibration, and then causing the vibration of the air next to it, so that you can clearly hear your friend's voice. This is much clearer than talking directly at the same distance and at the same volume, because sound travels better in solid than in air. )

Obedient and disobedient eggs

First, experimental materials: a few eggs, some sand, candles, markers or watercolor pens, colored paper.

Second, take two eggs, poke a hole in the small end, empty the yolk inside and dry the empty eggshell.

3. Fill the empty eggshell with sand accounting for about/4 ~1/3 of the total volume.

Take out one of the eggshells filled with sand, and you will be surprised at the obedience of this egg. No matter where you put it, this egg can keep its posture. Look, it can stand firmly on the bottle mouth like an acrobat. You can also keep balance on various slopes, but the road surface should not be too slippery. If the upper mouth is sealed, you can stand upside down. But in order to keep it in your posture, you'd better put it in a proper position and tap it a few times to flatten the sand inside.

5. Pick up another eggshell filled with sand, let it stand upright and tap gently to make the sand in a horizontal state, light the candle, let wax oil drop on the sand, and fix the position of the sand.

Six, this is a disobedient egg. No matter where you put it, it will always return to its original position. If you make a small hat for it with colored paper and draw a lovely face, it will become an interesting tumbler. Experimental principle: the original center of gravity of the egg is in the middle, so it is difficult for you to make it "obedient" or "disobedient". After loading the sand, the center of gravity of the egg is on the sand. Before the sand is fixed, with the change of the egg posture, the center of gravity of the sand, that is, the egg, is always located at the lower part of the egg in this posture, and when the egg is heavy below it, this posture is maintained. When the sand is fixed on the lower part of the upright egg, it becomes a tumbler due to the principle of center of gravity.

A serpentine windmill on a candle.

1. Materials: pins, empty film boxes, candles, thin plastic straws, pencils, cardboard, scissors.

Second, draw a spiral line on the cardboard and draw the end in the shape of a snake head.

Third, according to the figure, cut along the line, and you must poke a small hole in the middle, which can just pass through a thin plastic straw. This is the serpentine windmill.

Fourth, start making tripods now. First insert a pin into the rubber head of a pencil, then cut a small piece of thin plastic straw to seal one end, and put it on the pin to form a pen cap.

5. Open a round hole at the top of the empty film box and insert the pencil vertically.

6. The small hole in the middle of the serpentine windmill passes through the cap, and the windmill is completed.

Light a candle under the windmill and you will see the snake start to turn. If you put the windmill anywhere above the stove or heater, it will have the same effect. Why is this happening? Because warm air is lighter than cold air, rising warm air can drive the windmill to rotate. In daily life, the rising warm air keeps rising indoors, flows along the ceiling to the window, falls to the floor after being cooled by the window, and rises when it is hot ... The glider has no engine, but there is often a kind of warm air called thermal barrier (rising heat flow) that can make the glider rise.

Method for manufacturing mask