204 Simple Science Experiments ~ {ERG} - Page 4

LoneRanger · #46 05-24-2008, 12:38 PM

38. Coiled Adder

Cut a spiral-shaped coil from a piece of tissue paper about 4 inches square, lay it on a tin lid and bend its head up. Rub a fountain pen vigorously with a woolen cloth and hold it over the coil. It rises like a living snake and reaches upwards.

In this case the fountain pen has taken electrons from the woolen cloth and attracts the uncharged paper. On contact, the paper takes part of the electricity, but gives it up immediately to the lid, which is a good
conductor. Since the paper is now uncharged again, it is again attracted, until the fountain pen has lost its charge.

ะộ§ộะ мя žǒǒŁ ะộ§ộะ · #47 05-24-2008, 08:10 PM

hmmmm thx

LoneRanger · #48 05-28-2008, 11:54 AM

39. Water bow

Once more rub a plastic spoon with a woollen cloth. Turn the water tap on gently and hold the spoon near the fine jet. At this point, the jet will be pulled towards the spoon in a bow.

The electric charge attracts the uncharged water particles. However, if the water touches the spoon, the spell is broken. Water conducts electricity and draws the charge from the spoon. Tiny water particles suspended in the air also take up electricity.

Therefore experiments with static electricity always work best on clear days and in centrally heated rooms.

LoneRanger · #49 05-28-2008, 11:54 AM

40. Hostile balloons

Blow two balloons right up and join them with string. Rub both on a woolen pullover and let them hang downwards from the string. They are not attracted, as you might expect, but float away from each other.

Both balloons have become negatively charged on rubbing because they have taken electrons from the pullover, which has now gained a positive charge. Negative and positive charges attract each other, so the balloons will stick to the pullover. Similar charges, however, repel one another, so the balloons try hard to get away from each other.

LoneRanger · #50 05-28-2008, 11:55 AM

41. Shooting puffed rice

Charge a plastic spoon with a woolen cloth and hold it over a dish containing puffed rice. The grains jump up and remain hanging on the spoon until suddenly they shoot wildly in all directions.

The puffed rice grains are attracted to the electrically charged spoon and cling to it for a time. Some of the electrons pass from the spoon into the puffed rice, until the grains and the spoon have the same charge. Since, however, like charges repel one another, we have this unusual drama.

LoneRanger · #51 05-28-2008, 12:35 PM

42. Simple Electroscope

Bore a hole through the lid of a jam jar and push a piece of copper wire bent into a hook through it. Hang a folded strip of silver paper, from which you have removed the paper, over the back. If you hold a fountain pen, comb, or similar object, which has been electrically charged by rubbing on the top of the wire, the ends of the strip spring apart.

On contact with a charged object, electrical charges flow through the wire to the ends of the strip. Both now have the same charge and repel one another according to the strength of the charge.

LoneRanger · #52 05-29-2008, 02:48 PM

43. Electrical ball game

Fix a piece of silver paper cut into the shape of a footballer on to the edge of a phonograph record, rub the record vigorously with a woolen cloth and place it on a dry glass. Put a tin can about two inches in front of the figure. If you hold a small silver-paper ball on a thread between them, it swings repeatedly from the figure to the can and back.

The electric charge on the record flows into the silver-paper figure and attracts the ball, it becomes charged, but is immediately repelled because the charges become equal, and goes to the can, where it loses its electricity. This process is repeated for a time.

LoneRanger · #53 05-30-2008, 01:56 PM

44. Electric fleas

Rub a long-playing record with a woolen cloth and place it on a glass. If you toss some small silver-paper balls on to the record, they will jump away from one another in a zigzag motion.

If you then move the balls together with your fingers, they will hop fiercely away again.

The electricity produced on the record by rubbing is distributed in irregular fields. The balls take up the charge and are repelled, but are again attracted to fields with the opposite charge. They will also be repelled when they meet balls with the same charge.

LoneRanger · #54 05-31-2008, 11:43 AM

45. Puppet dance

Lay a pane of glass across two books, with a metal plate underneath. Cut out dolls an inch or so high from tissue paper. If you rub the glass with a woollen cloth, the dolls underneath begin a lively dance. They stand up, turn round in a circle, fall, and spring up again.

The glass becomes electrically charged when it is rubbed with the wool, attracts the dolls, and also charges them. Since the two like charges repel each other, the dolls fall back on the plate, give up their charge to the metal and are again attracted to the glass.

LoneRanger · #55 06-01-2008, 12:55 PM

46. High Voltage

Place a flat baking tray on a dry glass, rub a blown-up balloon vigorously on a woolen pullover and place it on the tray. If you put your finger near the edge of the tray, a spark jumps across.

A voltage equalization occurs between the metal and the finger. Although the spark is discharged with several thousand volts, it is just as harmless as the sparks produced when you comb your hair. An American scientist discovered that a cat’s fur must be stroked 9,200.000.000 times to produce a current sufficient to light a 75-watt bulb for a minute.

deepeshjain · #56 06-02-2008, 10:32 AM

nice exp yaaar

LoneRanger · #57 06-02-2008, 01:34 PM

47. Flash of lightning

Place a metal slice on dry glass, and on it a piece of hard foam plastic which you have rubbed well on your pullover. If you hold your finger near the handle of the slice, a spark jumps across.

When the negatively charged plastic is placed on the slice, the negative electric particles in the metal are repelled to the end of the handle, and the voltage between it and the finger becomes equalized. Plastic materials can become strongly charged. In warehouses, for example, metal stands for rolls of plastic are earthed, by the personnel because otherwise they often spark.

LoneRanger · #58 06-03-2008, 01:05 PM

48. Electric light

In many homes there is a voltage tester, generally in the form of a screwdriver. In its handle there is, amongst other things, a small neon tube, which you can easily remove. Hold one metal end firmly and rub the other on a piece of hard foam plastic which may be used for insulation. The lamp begins to glow as it is rubbed to and fro, and you can see this particularly clearly in the dark.

Since the plastic is soft, its layers are rubbed against one another by the movement of the lamp and become strongly charged with electricity. The electrons collect on the surface, flow through the core of the tiny lamp, and into the body which begins to glow .

The ancient Greeks had already discovered that amber attracted other substances when it was rubbed. They called the petrified resin ‘electron’. The power, which has caused such fundamental changes in the world since then therefore, gets its name - electricity.

LoneRanger · #59 06-04-2008, 01:22 PM

49. Magnetism Field Lines:

Lay a sheet of drawing paper over a magnet - of course you already know how to make a magnet - and scatter iron filings on it. Tap the paper lightly, and a pattern forms.

The filings form into curved lines and show the direction of the magnetic force. You can make the pattern permanent. Dip the paper into melted candle wax and let it cool. Scatter the iron filings on it. If you hold a hot iron
over the paper after the formation of the magnetic lines, the field lines, the pattern will be fixed.

LoneRanger · #60 06-05-2008, 02:19 PM

50. The earth’s magnetic field

Hold a soft iron bar pointing to the north and sloping downwards, and hammer it several times. It will become slightly magnetic.

The earth is surrounded by magnetic field lines, which meet the earth in Great Britain and North America at an angle between 60 and 80-degrees. When the iron is hammered, its magnet particles are affected by the earth’s magnetic field lines and point to the north. In a similar way, tools sometimes become magnetic for no apparent reason. If you hold a magnetized bar in an east-west direction and hammer it, it loses its magnetism.