Science Experiments Ideas

Science Experiments Ideas

1. Compressed air rocket :
Bore a hole through the cap of a plastic bottle, push a plastic drinking straw through it and seal the joints with adhesive. This is the launching pad. Make the rocket from a four inch long straw, which must slide smoothly over the plastic straw. Stick coloured paper triangles for the tail unit at one end of the straw, and at the other end plasticine as the head. Now push the plastic tube into the rocket until its tip sticks lightly into the plasticine. If you press hard on the bottle the projectile will fly a distance of 10 yards or more.
When you press the plastic bottle, the air inside is compressed. When the pressure is great enough, the plastic straw is released from the plug of plasticine, the released air expands again, and shoots off the projectile. The plasticine has the same function as the discharge mechanism in an airgun.

2. Bath game with a coin :
Stretch a strip of cellophane not plastic foil, 1 inch wide,tightly over a soup plate and fasten the ends with adhesive tape. Lay on the middle of the strip an average sized coin and pour water into the dish up to about 3 inch under the coin. The coin sinks slowly and reaches the water after several minutes.
The water vaporises, the cellophane absorbs the water particles from the air and expands until it reaches the water. But strangely enough it soon begins to tighten again, and the coin rises again slowly to its original position.

3. Compass needle :
Stroke a sewing needle with a magnet until it is magnetised and push it through a cork disk. Put the needle into a transparent plastic lid containing water and it turns in a north south direction. Stick a paper compass card under the lid.The needle points towards the magnetic North pole of the earth. This lies in North Canada and is not to be confused with the geographical North Pole, round which our earth rotates. The deviation declination of the magnetic needle from the true north is 80 in London and 150 in New York in a westerly direction and l0 in Chicago and 150 in Los Angeles, in an easterly direction.

4. Hanging water :
Fill a glass to overflowing with water and lay a postcard on it. Support the card with one hand, turn the glass upside down and remove your hand from the card. it remains on the glass, and allows no water to escape.With a glass of normal height, a weight of water of about 2 ounces presses on each square inch of card. On the other hand the pressure of air from below is about one hundred times as great on each square inch, and presses the card so firmly against the glass that no air can enter at the side and so no water can flow out.

5. Hot air balloon :
Roll a paper napkin into a tube and twist up the top. Stand it upright and light the tip. While the lower part is still burning, the ash formed rises into the air. Take care! The air enclosed by the paper is heated by the flame and expands. The light balloon like ash residue experiences surprising buoyancy because the hot air can escape, and the air remaining in the balloon becomes correspondingly lighter. Very fine napkins are not suitable for the experiment because the ash formed is not firm enough.

6. Electro magnet :
Wind one to two yards of thin insulated wire on to an iron bolt and connect the bare ends of the wire to a battery. The bolt will attract all sorts of metal objects.The current produces a field of force in the coil. The tiny magnet that the iron has a magnetic north and South Pole. If the bolt is made of soft iron, it loses its magnetism when the current is switched off, but if it is made of steel it retains it.

7. Paper saucepan :
Do you believe that you can boil water in a paper cup over a naked flame or in the embers of a fire! Push a knitting needle through the rim of a paper cup containing some water, hang it between two upright bottles and light a candle under the cup. After a little while the water boils but the cup is not even scorched.
The water removes the heat transferred to the paper and begins to boil at a temperature of 2120F or 1000C. The water does not get any hotter, so the paper does not reach the temperature, which is necessary for it to burn.

8. Flying coin :
Lay a sixpence or a dime four inches from the edge of the table and place a shallow dish eight inches beyond it. How can you blow the coin into the dish!You will never do it if you blow at the coin from the front on the false assumption that the air will be blown under the coin because of the unevenness of the table and lift it up. It will only be transferred to the dish if you blow once sharply about two inches horizontally above it. The air pressure above the coin is reduced, the surrounding air, which is at normal pressure, flows in from all directions and lifts the coin. It goes into the air current and spins into the dish.

9. Non inflammable material :
Place a coin under a cotton handkerchief and ask someone to press a burning cigarette on the cloth stretched over the coin. You need not be afraid of scorching the material, because only a harmless speck of ash will be left.The experiment shows that the metal of the coin is a much better conductor of heat than the cotton fabric. On rapid pressure the heat of the burning cigarette is immediately conducted away by the coin. There is only enough heat to cause a small rise in temperature in the coin, and the cotton does not reach a high enough temperature to burn.

10. Air :
Diving bell You can immerse a pocket handkerchief in water, without it getting wet stuff the handkerchief firmly into a tumbler and immerse it upside down in the water.
Air is certainly invisible, but it nevertheless consists of minute particles, which fill the available space. So air is also enclosed in the upturned glass, and it stops the water entering. If, however, you push the glass deeper, you will see that some water does enter, due to the increasing water pressure, which compresses the air slightly. Diving bells and caissons, used under water, work on the same principle.

11. Water from the desert :
We still read in the newspapers of people dying of thirst in the desert, but many of them could help themselves in this emergency. An experiment on a small scale in a sandbox will show you how to do it. Dig a fairly deep hole and place a beaker in the middle. Spread a suitably sized piece of transparent plastic foil over the edge of the hole and lay a small stone in its centre so that it dips down to the beaker in the shape of a funnel. The edges are fixed firmly into the sand. Soon, especially in sunshine, small drops of water form on the underside of the foil. They become larger and larger and finally flow into the beaker. The effect of the sun is to heat the ground strongly under the foil. The moisture held in the sand evaporates until the enclosed air is so saturated that small drops of water are deposited on the cooler foil. Even desert sand contains some moisture. If you also place cut up cactus plants into the hole, you will obtain enough water to survive.

12. Expanded air :
Pull a balloon over the mouth of a bottle and place in a saucepan of cold water. If you heat the water on a stove, the balloon is seen to fill with air.The air particles in the bottle whirl around in all directions,thus moving further apart, and the air expands. This causes an increased pressure, which escapes into the balloon and causes it to distend. If you take the bottle out of the saucepan, the air gradually cools down again and the balloon collapses.

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