Science becomes your gardener

Articles Required: A potted plant, a pot full of water, a piece of cotton string.

Many people are fond of indoor plants. But they hesitate to go in for them only because of the extra care they call for. For instance, who would look after them when the whole family is away on a vaca­tion? At some places the neigh­bours might take care of them, but you don't always have such caring neighbours. Then what to do? Shouldn't one have indoor plants only because one likes to enjoy some vacation. Now go wherever you want to without worrying for your plants. In your absence, the science will take over the task of watering your plants. Well, get to know here how it's done.

Place your water container at some high place and put your potted plant somewhere near it, at the bot­tom, as shown in the figure here. Now take your cotton string and insert its one end in pot's soil and dip the other in the container. As you do it, the water will first start moving up through the string and then starts going down alongwith the string to the pot. In scientific terminology this phenomenon is called 'Capillary attraction'. As long as the water remains in the container it will keep on wetting the string and thus flowing out of it to water the plant. So the size of the water container should correspond to the time of your absence and the number of plants to be watered. Yes, remember one important thing: for each plant there should be a different string although the water container can remain the same.

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Matchstick with sweet-tooth !

Articles Required: Amatchstick, a tub of water, sugar cube or sugar.

First of all, fill your tub with water. When the water surface is abso­lutely quiet and no bubbles are seen, just put a matchstick at the centre of the water surface. Now hang a sugar cube with thread at a distance of about three-four centi­meters from the matchstick in such a manner that half of it remains sub­merged in the water. Yes, one thing: while handling these things take care not to create any distur­bance in the water.

If you can't get a sugar cube, don't worry, you can just make a small pocket of sugar and hang it instead of the cube. After sometime you'll notice that the matchstick starts sliding towards the sugar cube, as if attracted by sweet. But do you know what is the actual reason behind it?

The sugar dissolves in water and makes a sweet solution. Being heavier than plain water, this sweet solution starts settling down. In this condition the water rushes from all directions to fill the gap. And as a result the matchstick is dragged along.

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Colour absorbs heat !

Articles Required: An ice slab, four cloth-pieces of dif­ferent colours (at least one black and one white) :- :-

Doesn't it sound strange that differ­ent colours absorb different amount of heat? Coming to think of it, what have colours to do with heat or cold ? But if you ponder a little deeply over it you would realise, that there is some weight in the argument. That's why we wear soft shades in summers and dark colours in winters.

How would you react if some friend calls it your whim and challenges you to prove it? Well, there is nothing to mind in that. After all'the basis of science is demonstration and experiment. So, how will you prove this to him? Come, we'll tell you here.

First of all, take a large slab of ice whose one surface is smooth and even. If it's not, make it so with the help of some hot object. Now take four rectangular cloth pieces, equal in size but in different colours. Yes, one of these must be white, one black and the other two of some other colours. Place them on the surface of ice as shown in the figure here and then put the ice slab in the sun for some time.

If the colours had no connection with heat whatsoever, it wouldn't have any special effect on the melt­ing of ice. But it doesn't happen like this. After some time you notice that the ice has melted under the cloth pieces at different rate and the interesting fact to note is that the depth of these 'enclosures' is not the same under all four pieces.The maximum ice has melted from underneath the black cloth and the minimum under the white piece, and under the other ones depend­ing upon their colour tones.

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Magic Butterfly !

Articles Required: A • thin cardboard sheet, two small coins, adhesive tape, one broom-straw.

What about having a 'magic but­terfly' that can sit on your fingertip without any support? Try making it today itself because it's very simple.
First of all, cut out a cardboard piece in the shape of a butterfly. Now paste a white paper on it and paint in pretty 'butterfly' colours.

Now paste a coin each under butter­fly's two wings as shown in the fig­ure. Also paste the broom straw right in its centre with its ends pro­truding a little from its mouth and tail. Well, your 'magic' butterfly is ready. If the coins have been pasted in such a way that its centre of grav­ity falls on the top of its head, it can be balanced on the tip of your fore­finger very easily to enchant every­body present around you.

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The Umbrella dance !

Articles Required: An umbrella with a "U" handle, a bottle in which umbrella handle can be inserted, string and a piece of chalk.

First rub the chalk on the string. Tie this string loosely to two points of opposite walls of a room. Now insert the umbrella handle in the bottle," and try to balance the bottle on this string. Once you've found the balancing point, your job is over. Now as you give it a light jerk it will start dancing like an acrobat—going up and down in a funny manner

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The Dancing couple

Articles Required: Two long thin nee­dles, a piece of card­board, a pair of scissors,kfive pieces of cork (one big, four small) and camphor.

I Make a figure of a dancing couple on the cardboard. Cut it along its outline, and stick it on the bigger cork with glue.

Once it's firmly stuck, pierce two needles into the big cork making a 90° angle, to each other. Now on their four ends, insert small corks. Try to make the base as compact as possible. But in any case its diame­ter should never exceed 5 cm.

Stick camphor grains on the sides of four outer corks with the help of pins and place it on water surface. If it has been made as described above, the cardboard couple will turn around and move about—as if the couple has begun its waltz.

In order to have a flawless perfor­mance, you must remove all traces of oil from the container and corks. You can do this by washing these articles well with hot water mixed with soda.

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Smoke goes down !

• Articles Required: An empty card­board shoe-box, two chimneys of kerosene lamp, can­dle, cigarette and matchstick.

Whenever you burn something the smoke moves upwards. Isn't it? Now, how would you react if you're asked to make it go downwards? Will you be able to do it? Well, once you try the experiment explained below, you'd naturally quip after that "Oh, it was so easy!"

Make two holes in your shoe-box as shown in the figure here and fix the chimneys in both of them. If you can't find such chimneys, you can use even the empty talcum powder tins after cutting their tops and bot­toms. Having done this, remove the shoe-box cover and put a burning candle just below the left chimney. Now replace the cover and paste cello-tape on the joint of box and its cover to restrict air entry from the slit.

Now, if you light a cigarette and bring it on top of the second chim­ney, something interesting would happen. The cigarette smoke, instead of going upwards, would start travelling downwards. Isn't that strange?

Let's explain the logic of it. You know very well that the hot air is lighter than the cool air. The air above the candle becomes hot, moves upwards, and escapes from the left chimney. Now, this gap has to be filled and as there is no inlet for the air except the right chimney, the air comes in through it, creating a force of suction which draws the cigarette smoke alongwith it. So instead of going up smoke goes downwards.

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Magic Pictures !

Articles Required: Two books, one glass sheet, cork, brush, a little glycerine.

With the help of brush and glyce­rine, make a figure on the glass sheet. Now, show it to the specta­tors from the reverse side. And take care to keep the light source also on the reverse side.
First grate the cork into fine, smaller pieces. You can do this with the help of a grater used in the kit­chen. Put these pieces between the books and then draw the figure on the glass sheet as described above. Now lift the top book and put glass sheet on the cork pieces with the glycerine-coated side facing downwards. If you start rubbing the sheet' top with woollen cloth, it would be charged with electricity.. As a result, the cork dust would get stuck to the glass. But when the rubbing is stopped, most of the dust would drop back on the table, except from the glycerine-coated part.

Now lift the sheet and blow off the extra cork dust around the figure. Your picture is ready. A magic pic­ture for those who don't know the secret about glycerine!

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Picture made by Fire

Articles Required: Cobalt chloride, cobalt acetate, cobalt oxide dis­solved in acetic acid with a little potas­sium nitrate, brush a sheet of paper.

You must've heard of special inks which, when used on the paper, remain invisible, and can be seen only through some special method. But, here instead of inks we are going to talk about colours that have almost similar properties. In beginning the picture made with these colours will remain invisible but on heating a little it will come to life with cheerful pink, blue and green colours.

To make such colourful pictures, prepare three solutions in separate glasses. Be careful to keep them separate even when you are using them on paper.

Your three solutions are colour­less, so when you make a painting with these on the paper it would appear invisible. However, while applying the solutions you've to keep one solution from touching the other. Of course this is a difficult task, but with a little care you can do it. When you've finished with one 'colour' you'll have to wash the brush properly. When your picture is dry and you show this blank paper to somebody, he wouldn't be able to even imagine that a colour­ful picture is hidden therein.

Well, your main task is over and now you just have to raise the .cur­tain of suspense. As you bring the sheet near the fire, colourful attrac­tive picture would emerge on your blank paper. Do you know how? Simple! Due to the effect of heat cobalt chloride will turn into green colour, cobalt acetate into the blue and cobalt oxide into pink!

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Pretty garden—without plants !

Articles Required: A large glass case, water glass, metallic salts and water.

Most of us live in crowded places— where we don't even have commun­ity parks, what to talk of a house garden. Then how would you react if we show you a way to grow a garden inside your own room and that too within a few hours? Aren't you surprised?

Come, let's begin. First of all, put a thick layer of sand in the glass case. Now pour water-glass and add plain water in it. You know what water-glass is? It is the same thing which is used to preserve fish eggs in acquariums.

Having got this ready, you have to sow the 'seeds'. Your 'seeds' are the grains preferably of 1 mm size, of metallic salts like copper chloride, copper sulphate, lead nitrate, man­ganese sulphate, aluminium sul­phate, ferrous sulphate, ferrous chloride, copper nitrate, nickle sul­phate, cobalt chloride and cobalt nitrate etc. These are available from a chemist shop.

These 'seeds' must be embedded in the sand properly. Moreover, make sure that the case doesn't shake, asthis can displace the salts and spoil the show.

A little while after sowing your 'seeds', you can witness the emer­gence of exotic colourful plants of different sizes and shapes. An ideal showpiece for your living room that will impress not only your family but also friends and guests!

However, it can take a few hours for the garden to come up completely. But when you wish to change the water, you'll have to siphon it off carefully without disturbing the sand.

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Pulse moves pin !

Articles Required: A drawing pin and a match.

• You have often noticed the doctors or 'vaidyas' feeling the pulse of their patients to diagnose the dis­eases. In fact, the heart pumps the blood to the various organs of the body through arteries. So, just by" putting the finger at some particu­lar artery, the pulse rate can be gauged. And this helps in the diagnosis.

Just put your fingers at the right place on wrist of your other hand. Can't you feel it? Here we are telling you a magic trick through which you will not only feel but also be able to 'see' it clearly.

Take the match and insert the drawing pin into its back. Make sure that its a pin with a curved top. Now if you put this pin on the -point where you can feel the pulse, the match will move back and forth with every pulse beat. And thus you will not only feel but also 'see' the pulse movement.

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Soap-driven boat !

Articles Required: A cardboard piece, soap, a pan full of water.

• A boat driven by soap! Doesn't it sound strange? Well, not only it's possible, you can even make one yourself and simply surprise all your friends.

Cut out a boat-like figure from the cardboard piece, and fix two soap pieces at.its back as shown here. Now, if you want, your boat should follow a circular path instead of going straight, you can join a card­board piece at the back to act like a rudder.

Well, your boat is ready. As you put it in a big pan of water, it will start sailing. How does it happen? As the soap dissolves in water, it reduces the surface tension at the back of the boat and due to the difference in surface tensions on two sides of the boat, it is pushed forward. But as soon as the soap gets dissolved in all of water the boat becomes station­ary. Why?

Because of the dissolution of soap in the water/the surface tension of the whole body of water becomes the same. And thus the boat can't move forward any more. So it is suggested that once it happens, you change the water. And if you can go down to some pond etc. that would be ideal.

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Water boils in a Paper Pot

Articles Required: A sheet of thick paper, paper-clips, water, fire.

I You've of course seen water boiling in ali kinds of utensiis but when the pot happens to be of paper, things are more than interesting. Doesn't it seem incredible? Well, why don't you try yourself.

As shown in the figure here, make a paper pot wjth the heip of the clips. Now fill it with water and burn a candle under it. Be carefui about one thing. The flame should not reach that part of the pot which is untouched by water.

After some time, the water will start boiling without burning the paper. How does it happen? In fact the water takes away ail the heat before the paper can reach its burning point. The water boils at 212°F and at this temperature it gets con­verted into steam. And as the temperature doesn't go above it, the pot can't reach its ignition point which is much higher than the boil­ing point of water.

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Water that boils instantly !

Articles Required: A strong solution of ammonia water, a beaker, stove or heater.

If you don't believe it, try this exper­iment. Take a beaker or any other glass-vessel which won't break on a heater. Fill three-fourths of it with the strong solution of ammonia water. Now the moment you put it on the heater, almost immediately bubbles start rising from the bottom of the liquid to its surface. Can any liquid boil so fast? Would you believe it? No! Then what happens in this case ? Why do bubbles form ?

All this happens because you have a very strong ammonia solution and it means that water contains a great deal of ammonia. Thus when it's heated it's unable to contain all the ammonia gas any more. So, as the temperature rises the ammonia emerges out of it in the form of bub­bles, and you get the impression that the solution is about to boil.

When you put water in a pot to make tea, what's the indication that it's about to boil ? The bubbles! Isn't it? But be careful! Whenever the bubbles are seen that doesn't mean that the liquid is about to boil. This phenomenon is true only within the boundary of your kitchen.

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Water boils without fire

Articles Required: One round-bottom flask with a tight-fitting cork, water and arrangement to heat it.

We all know that water boils at 100° C. But this fact is not true in all the conditions. So we can say that the boiling point of water is 100° C at the sea-level under normal condi­tions. So higher you go, the air pres­sure decreases correspondingly, and as a result the water boils at a much lower temperature. By the same principle, deeper one goes the boiling point of water increases correspondingly.

So, if you want to prove this fact through experiment just fill your flask with water and put on fire to heat. Now when the water begins to boil, and the flask is full of steam produced by the boiling water, tighten the cork on its mouth. Remove it from the fire and hang the flask upside-down as shown in the figure here and make sure that the water is not boiling now. Once the water surface-is quiet, just squeeze some cold water on its top with the help of a cloth piece. But wt at's this? With little sprinkling of cold water, the water inside the flask starts boiling again! Do you know its reason?

By sprinkling cold water on the flask, some of the steam inside gets converted into water. This leads to a decrease in pressure and so water starts boiling once again and that even without fire!

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Funny Diver !

Articles Required: A tall glass, dropper, one thick-rubber balloon, rubber bands.

Fill the glass with water leaving one-eighth of it empty. Then fill the dropper also with water sufficient to hold it erect in the glass. Now float the dropper in the water of the glass and stretch a rubbr balloon on its mouth. To make it air-tight use rubber bands on top. That's all. Your preparations are done!

Just press the rubber top lightly with finger tip. What happens? The dropper, like an expert diver, dives towards the bottom! If you keep on pressing it, it will reach and touch the bottom. And on the contrary, as you take away your hand from the rubber sheet, the dropper jumps back to the water surface.

Under pressure, the air contracts more than water. So as the rubber lid is pressed down, the air is pres­surised and this in turn puts pres­sure on the water as a result of which the water forces its way into the dropper and pushing its air,.fills it. So the dropper dives down. That's the secret of thi? extra­ordinary diver.

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Wow, what an air-gun

Articles Required: A 15-cm long metal or glass tube, potato, pencil.


Cut 4-5 mm wafer-thin potato slices. Now take the metal tube and press hard its one end against a potato slice. This end will get closed. Now similarly press the second end and close it also. With the pencil, force the potato piece of one side a little further down in the tube. Now. point it towards the target. Use your .pencil as the trigger and push it in the tube. The wafer on the other side will act as a shot and hit the target with a 'pop' sound!

So, how about making a harmless and inexpensive airgun? An airgun—in real sense.

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