More than 150 experiments, each accompanied by a charming period engraving, promise to amuse and astonish viewers. Stunts include making an egg waltz and a banana peel itself, balancing a plate on the point of a needle and a cup of coffee on a knife blade, changing water into wine and back again, and scores of other exploits. Created by French engineer and science educator Arthur Good, these experiments are regarded as the foundations of the modern approach to science education.
More than 150 experiments, each accompanied by a charming period engraving, promise to amuse and astonish viewers. Stunts include making an egg waltz and a banana peel itself, balancing a plate on the point of a needle and a cup of coffee on a knife blade, changing water into wine and back again, and scores of other exploits. Created by French engineer and science educator Arthur Good, these experiments are regarded as the foundations of the modern approach to science education.
Magical Experiments: Scientific Amusements to Entertain and Instruct
336
Magical Experiments: Scientific Amusements to Entertain and Instruct
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Overview
More than 150 experiments, each accompanied by a charming period engraving, promise to amuse and astonish viewers. Stunts include making an egg waltz and a banana peel itself, balancing a plate on the point of a needle and a cup of coffee on a knife blade, changing water into wine and back again, and scores of other exploits. Created by French engineer and science educator Arthur Good, these experiments are regarded as the foundations of the modern approach to science education.
Product Details
| ISBN-13: | 9780486840703 |
|---|---|
| Publisher: | Dover Publications |
| Publication date: | 06/12/2019 |
| Sold by: | Barnes & Noble |
| Format: | eBook |
| Pages: | 336 |
| File size: | 93 MB |
| Note: | This product may take a few minutes to download. |
About the Author
Read an Excerpt
CHAPTER 1
MAGICAL EXPERIMENTS;
OR,
SCIENCE IN PLAY.
EXPERIMENTS IN PHYSICS.
The Plate on the Point of the Needle.
Everybody has seen the jugglers in the circus spinning plates, and even dishes, on a pointed stick For the most part, the plates they use are made of wood or metal, and their equilibrium is due to centrifugal force, which will fail just as soon as the rotation is too weak to overcome the force of gravity.
But here is a way to balance a china plate on the point of a needle, and even to cause it steadily to spin upon this delicate support.
Cut a couple of corks down the middle, through the long axes, and in the extremity of the four halves thus obtained insert as many forks, inclined to the smooth sides of the corks you have just cut at a little less than a right angle. Place these four corks, as in the illustration, round the rim of the platter, at equal distances from one another, and see that the teeth of the forks are in contact with the rim, to prevent them swaying like so many pendulums.
The little system we have now constructed is capable of being balanced, even firmly so to speak, upon the point of a needle, whose eye-end is buried in the cork of an upright wine-bottle. With a little care to prevent the plate slipping, you may even cause it safely to rotate at a fair rate of speed, which, when once set in motion, will continue for a long while, because the friction at the point of contact is almost nil.
The Egg that will Stand up.
Fix two forks firmly in a cork, as in the illustration, observing that they are of equal weight and at equal angles with the perpendicular ; gently hollow out the lower portion of the cork with a sharp penknife, so that it may fit with some exactness one of the ends of the egg. Now poise the other end of the egg carefully on the edge of the neck of the bottle ; see that the egg is in the vertical position, and after a few tentative shakes, not letting go of it at once, yon can ascertain that the whole is in a state of equilibrium, an effect that is obtained, of course, by our thus placing the centre of gravity below the point of support.
One Way of Halving a Pear.
How are we to manage to get the knife into the exact position under a pear, suspended as high as possible by a thread from the ceiling, so that the fruit shall fall precisely on the blade as soon as the thread that held it has been burned ? We shall not require a plumb-line in order to manage this ; there is an easier way-to dip the fruit in a glass of water, which we put out of the way when it has served its purpose. A few drops falling from the fruit will spatter one particular spot on the chair or table underneath, on which we put a private mark. These preparations must be made in secret, so that when the spectators assemble they find nothing but the pear suspended, and know nothing of the drop of water that fell, which is our little friendly guide to success in this pretty experiment.
At the anticipated moment, you place your knife upon the spot that you have marked, and the pear will infallibly split itself in exact halves upon your knife-blade.
Or you may arrange the experiment as in the picture, with two knives instead of one, causing a sufficient number of drops of water to fall, till you have ascertained the exact spot at which the blades should cross each other. The pear will cut itself into quarters, which you gather on the plate you have placed in position underneath, and present to the spectators in token of your skill.
How to Pierce a Pin with a Needle.
The pin is thrust half way into a cork, from which hang suspended, as in the illustration, a couple of penknives of equal weight. Should they happen to be of different sizes, you can maintain the equipoise by varying the angle of the blades. Balance the head of the pin on your forefinger, and make sure, by swaying the knives gently to and fro, that they will hold themselves horizontal. Next balance the body of the pin on the point of a needle whose eve is run into another cork in an upright wine-bottle. By blowing on the cork that holds the knives, yon will set your little system rotating on the point of the needle. Further, the needle, being harder than the pin, which is only brass, will penetrate it, and bore a hole, which, if the experiment be continued long enough, will traverse it completely, to the astonishment of the beholder.
The Housekeeper's Terror.
The problem here is to balance a cu p of coffee on the point of a knife, upright. 'f he apparatus necessary is extremely simple ; you will find it at hand upon the table — with a cork and a fork you have what is wanted for the purpose — not forgetting a little address upon the operator's part.
Insert the cork in the handle of a coffee-cup, vigorously enough to fix it pretty tight, hut not so tight as to snap the handle off. Stick the fork into the cork, straddling the handle of the cup, two prongs on one side, two on the other — unless it be a three-pronged fork — gently inclining the hand le of the fork toward the bottom of the cup.
The centre of gravity of the system being thus successfully lowered, place your cup, a quarter full of steaming coffee, on the point of a knife or dagger, and verify, by a few tentative pushes to and fro, that the cup is in exact equilibrium. Cups being, for the most part, highly glazed, see that the hand that holds the dagger does not tremble, or it will make all haste to slip and spill your steaming coffee. To begin with, you had better keep your left hand near the handle of the fork, so as, in case of threatened accident, to be able to seize your cup in its extremity.
One last precaution : If you are thirsty, drink your Coffee — first.
How to Pierce a Nickel with a Needle.
To pierce a nickel with a needle, especially if the needle be a very fine one, seems a difficult, if not an insoluble, problem. It is, nevertheless, a very simple feat.
To succeed, insert a needle in a cork, so that the point be just apparent, and, if the needle project at the other end, snap off the remainder of it with a pair of shears.
Now place your nickel on a couple of wooden blocks, as in the illustration, and strike a sharp blow with a heavy hammer on the prepared cork that you have placed above it ; or it will do if the nickel is simply laid upon a single block of soft wood.
The needle, being unable to bend either way — thanks to the friendly support of the cork — is forced to go one way, and will pierce the nickel, or even a silver quarter, with the greatest ease ; for, as we know, the steel of the needle is harder than the bronze or the silver of the coin.
The Diving Bell.
When we plunge an empty glass upside down into a bowl of water, we see that the level of the water in the glass is a long way below the level of the water in the bowl. This well-know phenomenon permits us to give an easy and am using demonstration of the use and functions of the diving bell, in which workmen, though far below the level of the water, can breathe and do their business at will.
To render the experiment visible to your audience, dispose your apparatus as follows : The vase containing the external water is a cheese-cover upside down, supported on an empty pickle-bottle, in to which its handle enters, and on which it safely rests. You have thus a transparent arrangement, enabling you to see everything that goes on in its interior. Assure yourself by actual experiment, that, in plunging the glass into the water, the level within is far lower than that of the surrounding fluid.
Relying on this principle, yon may safely make the following demonstration : Dip a lump of sugar below the water-level without wetting it.
Dispose your lump of sugar in the middle of a bung or mustard cork, and place your glass upon the floating cork so as to surround it. Now lower the glass, taking care to keep it vertical, so that t he cork does not turn a somersault and drown its precious burden. You will now be able to hold the rim of your glass against the lower surface of your improvised vase as long as you desire, and when you lift your glass, and with it raise the cork and its submarine passenger, you will perceive the lump of sugar still entirely dry, the compressed air enclosed in the glass having prevented the water from coming into contact with it.
A Bottle, or an Acrobat ?
How are we going to balance a bottle on its side upon a cord stretched across the room ? It seems impossible ; yet it is easy. As in the illustration, all you have to do is to insert the curved handle of an umbrella or parasol into the mouth of the bottle. In order to prevent the bottle from slipping, it is sufficient to chalk the cord at the point of support, just as acrobats rub white chalk over the soles of their shoes, and for the very same purpose.
The figure to the right shows us a novel method of decanting a bottle of port-wine without shaking u p the dregs. Into the neck of the bottle, instead of a parasol handle, insert the curved handle of a kitchen ladle, such as cooks use in the preparation of soup ; instead of the cord in the first experiment, make use of a wide strip of cotton ; and in order to make the bottle gradually bow toward the ground, yon must pour, very gently and without shock, a little at a time, sufficient water into a receptacle that you have suitably bitched on to the ladle.
Let me add, that this experiment is quite safe, in theory : it will be better, in practice, to use a bottle of vin ordinaire, instead of fine old port.
The Bottle in Peril.
My readers will exclaim aloud at this illustration ; and, indeed, it appears to me it would be a pity not to publish the way, no less new than neat, in which this feat is accomplished. By this experiment, you can carry a caraje of water, a bottle of wine, and three wineglasses, on a platter whose diameter is hardly large enough to contain the base of the caraje. I am ready to admit, as my title proves, that the bottle is not in the safest of positions ; but is it not the very difficulty of the attempt that makes the charm of these experiments in equilibrium For the rest, would it be a very great disaster, if, in consequence of a, mistake, one should do a good turn to the glass industry of the country, and gladden the heart of the crystal-merchant by a miniature smash ?
Let us, for the nonce, brave the housekeeper's often-merited censure, and make plain the way we are to build our brittle edifice. At the onset, we are confronted with a difficulty. The illustration, taken from a photograph, shows well enough the respective positions of the six pieces ; but how are we to make clear the precise way of getting them into place ? The theory is, in a word, as follows : Place the feet of your three glasses between the bottom of the bottle and the neck of the carafe. But in practice it is not quite so simple. I will here confine myself to a few words of advice as to how to diminish the chance of accident.
At first, in order to succeed in the experiment, set the carafe on a table instead of holding it in the hand : you will do exceedingly well on the first attempt if you avoid an accident. An assistant or two will prove acceptable, and I need not say that you should choose them amongst the neatest-handed of your acquaintances.
Let three of them, then, hold each a wine-glass by its body, and group themselves around the platter placed upon a centre-table. The fourth holds a bottle half full of wine (water will be best at first). The four operators act with military precision : first, the three glass-holders pose each the foot of his wine-glass on the edge of the neck of the carafe, in such a way that they are equally distributed and stand out horizontally.
At this moment, the fourth gently poses the bottom of the bottle, like an extinguisher, over the feet of the three glasses, assuring himself by pressing lightly on the bottle, and then lifting it up gently, that its weight is barely sufficient to maintain an equilibrium. The glasses being still held by the assistants, the fourth one is to pour into the bottle, by means of a funnel, enough water to maintain the balance of the system, so that now no longer t he glass-holders find them heavy on their hands. Each of them now quits his hold, and the last can cork the bottle. Now is the time, the experiment having been performed in seclusion, to call in the spectators to admire your handiwork.
One last precaution : before you place the glasses in position, make sure, by putting them foot to foot, that they are exactly equal in diameter.
And now I wish those of my readers who intend to try the experiment a happy delivery l
The Barrel and the Bottle ; or, The Automatic Cellarman.
The problem is, with a barrel full of wine, bung upward, and a commmon wine-bottle, how to fill the bottle with wine, through the bung-hole, without the aid off any other apparatus save the bottle.
Here is the solution : Your barrel being completely full of wine, you fill the bottle with water ; then temporarily closing its neck with your thumb, you plunge it quickly upside down into the bung-hole, quitting at once your control of its contents. Now you leave the bottle in the position of the illustration, and in a few minutes you will actually behold the wine, which is lighter than water, mounting of its own accord into the bottle. The water subsides meanwhile in the barrel. At the close of the experiment, the bottle, at first full of clear water, will be full of wine.
Eruption of Vesuvius.
Place at the bottom of a large, flat glass vessel of water a little flask containing some red wine. The flask is sealed with a cork having a small hole bored through it by means of red hot wire in the direction of its axis. We have already seen that, in consequence of the difference in their densities, wine will fall upward into water ; and accordingly we shall soon see the ruby liquor escaping in a small but slowly widening thread that ascends toward the top of the water.
The following is a picturesque and effective method of presenting this well-known phenomenon to the eye : From clay, or simply sand or ear t h, fashion an imitation mountain at the bottom of your vase. Imagine it Vesuvius. In this miniature mountain you conceal the flask of wine, only taking the precaution to leave a small hole to allow the thread of wine to escape : this is the crater.
Now gently give the water in the vase a circular motion with the hand ; call in your spectators ; and in the red, swirling plume of wine that escapes, as though agitated by the wind, you have an exact representation of the eruption of Vesuvius.
Water Changed into Wine.
We are not going to repeat the miracle at the marriage feast of Cana ; but the experiment now proposed is not ·without its interest to scientific amateurs.
Take two drinking goblets of equal diameter, which I will call respectively A and B, and plunge them in a pail of water, holding one upright, the other upside down. As soon as both are completely full of water, and not a bubble of air remains in them, put them together, brim to brim ; and uow, with their axes vertical, A below (the right way up) and B above (upside down), remove them carefully from the water. Having allowed them first to drip the outside moisture on a plate, and wiping them dry, you will find that B remains full of liquid, even if you displace its brim the least in the world, so as to leave visible a little thread of water, whose function we shall presently perceive. On the foot of B now place a smaller glass, C, full of red wine ; and you may announce to your friends that, without touching either one or the other of the three glasses, without even covering them with the traditional magician's handkerchief, you are about, under the very eyes of the public, to cause the wine in C to pass into the glass B without a drop of it obtaining entrance into A. The operation, as we shall see, is double : first, it is necessary to get the wine out of the small glass C ; second, to cause it to penetrate into the upside-down glass B. A fibre of tapestry wool dipped into the wine in the upper glass, whose two extremities are left to hang outside, will form, on account of its capillarity, an excellent siphon ; and soon at each end of the thread we shall perceive a trickling drop of wine, which will grow larger and larger till it drops upon the foot of B, and then, overflowing, down the sides of the glass. Thus the wine will gently creep toward the brims of the two larger glasses ; and there, strange to say, instead of continuing its descent under the action of gravity, we shall see it creeping upward and sideways between the rims of the glasses.
This phenomenon is due to capillarity, and recalls the experiment of making water mount between two plates of glass that have been closely juxtaposed, or with the interior of a glass tube of very small diameter. shall behold our wine, once having obtained an entrance to the lower system, mounting in slender red columns to the top of the water in B, lending it a deeper and deeper tint as it advances, which wm appear paler as the centre approaches.
(Continues…)
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