A piece of carbon, pith, or even a small piece of damp tissue-paper will serve as anelectroscope to test the presence of static electricity.
He used the condensing electroscope as one means of proving that two dissimilar metals become charged differently when in contact.
When a sharp metallic point is held near the knob of a charged electroscope the leaves quickly come together.
If the rod bearing the cap is held near a charged electroscopelittle or no effect is noticed.
If a body charged similarly to the electroscope or positively, is moved toward the electroscope the leaves separate further.
If a metal can is charged strongly while standing on an insulator, tests made by means of the proof-plane and electroscope show no charge on the inside.
An electroscopeis a device employed to test the presence of an electrical charge.
If a circular metal plate several times the diameter of the top of the electroscope is laid upon the latter (see Fig.
The kind of charge upon a body may be determined with an electroscopeas follows: Make a proof-plane by sealing a small metal disc on the end of a hard rubber rod.
The metal plate gives the electroscope a greater surface and hence greater capacity.
If the charged vulcanite rod is brought near the electroscope, the leaves separate further That is, a charge like that on the electroscopemakes the leaves separate further.
If while the charged rod is held near, the metal top of the electroscope is touched by the finger the leaves at once fall together showing that the repelled negative charge has escaped from the electroscope (Fig.
Therefore, it is said that electroscope C mentioned above has a greater potential thanelectroscope D.
Should the metal top of an electroscope have sharp corners?
Placing insulators, such as a sheet of glass, between the charge and the electroscope does not affect the result, which is apparently brought about by the action of the electric lines of force.
The leaves of the latter will separate showing that the electroscope is charged.
Faraday found that if a sensitive electroscope is surrounded by a wire mesh screen (see Fig.
If a sharp tack be dropped point up on the plate of an electroscope the latter is quickly discharged.
Assistant standing on the insulating stool and touching the disc of the electroscope whilst being struck with a dry handkerchief.
Cut some chips from a piece of wood with a knife attached to a glass handle, and as they fall on to the electroscope the leaves are repelled.
A very similar form of electroscope was employed by J.
It was then found that when the end plates of Volta's pile were connected to an electroscope the leaves diverged either with positive or negative electricity.
To detect electrification it is best to charge the electroscope by induction.
A third great use of the electroscope is therefore to detect electric conductivity either in the air or in any other body.
In a dry atmosphere sulphur or amber is an early perfect insulator, and hence if the air in the interior of the box is kept dry by calcium chloride, the electroscope will hold its charge for a long time.
The uses of an electroscope are, first, to ascertain if any body is in a state of electrification, and secondly, to indicate the sign of that charge.
Henley and others devised the pith ball, or double straw electroscope (fig.
As already mentioned, Faraday remedied this defect by coating the inside of the glass vessel in which the gold-leaves were suspended to form an electroscope with tinfoil (see fig.
To employ the electroscope as a means of detecting radioactivity, we have first to test the leakage quality of the electroscope itself.
The sign of charge is then determined by holding near the electroscope a glass rod rubbed with silk or a sealing-wax rod rubbed with flannel.
Curie employed an electroscope made as follows:--A metal case (fig.
Moreover not only does this order prevail in normal forms, but again and again it is to be seen in newly-sprung varieties, which by general consent cannot have been subjected to a prolonged Selection.
If the electroscope be screened from the alpha-rays, it is found that the activity of the rod in beta- an gamma-rays increases for some 35 minutes and then diminishes (Fig.
Is the "natural" leak of a brass electroscope due to an intrinsic radio-activity of brass, or to traces of a radio-active impurity on its surface?
An electroscope may be made of a strip of gold-leaf attached to an insulated brass plate and confined in a brass vessel with glass windows.
Does the feeble electric conductivity always observed in the air contained within the walls of an electroscope depend on ionizing radiations from the material of the walls themselves?
How to Make an Electroscope [103] An electroscope for detecting electrified bodies may be made out of a piece of note paper, a cork and a needle.
The galvanic pile employed in this electroscope is that invented by Zamboni.
This electroscope is, beyond doubt, one of the most delicate ever constructed, and is well adapted to show small quantities of positive and negative electricity.
By touching the carrier to any charged body, it, also, becomes charged; and the nature of the charge may be determined by the use of a previously charged leaf electroscope (Exp.
Did any electrification go to theelectroscope from E S?
A) With the charged E R charge the electroscopenegatively by conduction (Exp.
Two sheets of aluminum-leaf for the leaf electroscope (Fig.
A delicate gold-leaf electroscopewould be ruined by coming in contact with a heavily charged body.
D) Charge the electroscopewith F C until the carbon is strongly repelled.
The electroscope was charged with + electrification by taking - out of it.
C) Discharge the electroscope and recharge as in (A).
Compounds of radium affect a photographic plate or electroscope even through layers of paper or sheets of metal.
It affects photographic plates even in complete darkness, and discharges a gold-leaf electroscope when brought close to it.
As electroscopes used to be constructed, these walls were made of glass imperfectly covered, if at all, by conducting material, and the electroscope was quite indefinite and uncertain in its action.
Such a difference is what a gold-leaf electroscope indicates for its gold leaves and the walls surrounding the air-space in which they are suspended.
But they tell us that the electroscope does not show any signs of electrification in the evaporated moisture.
The electroscope is not made to detect the presence of energy except when set free as electricity.
Let us suppose that the gas is made conducting by Rontgen rays produced by a vacuum tube which is placed in a box, covered except for a window at B with lead so as to protect the electroscope from the direct action of the rays.
If a slow current of air is drawn by the water pump through the testing vessel, the charge on the electroscope will gradually leak away.
V is a testing vessel in which an electroscope is placed.
First charge the gold leaves of the electroscope by touching the knob with a glass rod rubbed on silk.
When an electrified body is held near the electroscope it is attracted or repelled thus indicating the presence and nature of the charge.
Let charged rods or other powerfully charged bodies be brought near the electroscope outside the cage.
The earliest electroscope devised consisted of a stiff straw balanced lightly upon a sharp point; a thin strip of brass or wood, or even a goose quill, balanced upon a sewing needle will serve equally well.
The gold leaf electroscope can be further used to indicate the kind of electricity on an excited body.
An ice-pail P connected with the gold leaves of anelectroscope C, is placed on an insulating stand S.
The gold leaf electroscope will also indicate roughly the amount of electricity on a body placed in contact with it, for the gold leaves open out more widely when the quantity of electricity thus imparted to them is greater.
Another form of electroscope is the pith ball pendulum, shown in figs.
While it is being lowered the leaves of the electroscope diverge farther and farther, until K is well within the pail, after which they diverge no more, even when K touches the pail or is afterwards withdrawn by the insulating thread.
To repeat the experiment in modified form, let an electroscope be placed beneath a bird cage or wire netting, as in fig.
If now the brown paper be brought near the electroscope, the leaves will be seen to diverge more, proving the electrification of the paper to be of the same kind as that with which the electroscope is charged.
The leaves of the electroscope will diverge with positive electricity.
If whilst holding the ebonite sheet over the tray the latter is also touched with an insulated brass ball, then this ball when removed and tested with the electroscope will be found to be negatively electrified.
On the plate of a gold-leaf electroscope place a metal canister having a loose lid.
It will be found that as it does so the gold-leaves of the electroscope diverge, but collapse again if the ball is withdrawn.
At small heights Exner (27) has employed captive balloons, provided with a burning fuse, and carrying a wire connected with an electroscope on the ground.
When a charged body is brought near the electroscope the leaves become charged similarly by induction.
If the approach of the unknown charge causes a further divergence of the leaves, then it is of the same kind as that with which the electroscope is charged.
The general appearance of one form of electroscope is shown in fig.
Bird repeated the question at the next post and was told that the electroscope there was losing its charge in seven minutes.
If I then touch the ball with it, the charge is transferred to the electroscope and causes the two sheets of gold-leaf to stand apart at an angle.
As he touched the ball of the electroscope the sheets of gold-leaf separated and stood apart at a right angle.
The radio operator set up his device, while the other man rubbed his coat sleeve briskly with the hard rubber and then touched the ball of the electroscope with it.
As they climbed out, Carnes saw that one of them carried a portable radio sending set, while the other bore an electroscope and a rubber rod.
Result:--On examination, the electroscope was found to be completely discharged!
After a little time, there was the metallic scraping as before, and on examination the electroscope was found to be completely discharged.
Again, in his Reality of Psychic Phenomena, he says: "I took the electroscope to the table in the corner; then placed it in the circle near the medium.
I took the electroscope to the table in the corner of the room and tried to recharge it, but found I was unable to do so even after repeated trials.
I now show you by thiselectroscope that these charges are unlike in character.
Of this each one present must judge, but I will connect it with this electroscope (Figs.
Bohnenberger’s Electroscope indicates the presence and quality of feeble electric currents.
A sensitive gold-leaf electroscope is attached to the aluminium plate, and its image thrown upon the screen.
There is a liberation of negative electrons at the surface of the aluminium; these, under the attraction of the positive body, are rapidly removed as ions, and the electroscope charges up positively.
Again, if I simply electrify negatively this aluminium plate so that the leaves of the attached electroscope diverge widely, and now expose it to the rays from the arc lamp, the charge, as you see, is very rapidly dissipated.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "electroscope" in a variety of sentences. We hope that you will now be able to make sentences using this word.
