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School science experiments (view source)
Revision as of 15:05, 22 August 2014
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<br>'''Shared by/ Source'''<br>
<br>'''Shared by/ Source'''<br>
Praveen Kamath Sir, GHS Ankanahally, Somavarpet Taluk, Kodagu
Praveen Kamath Sir, GHS Ankanahally, Somavarpet Taluk, Kodagu
=The blue bottle=
<br>'''Materials'''<br>
10g of glucose, 8g of KOH, 300ml of distilledwater, 6-8 drops of methylene blue indicator, 500ml round bottom flask.
<br>'''Procedure'''<br>
Dissolve 8g of pottassium hydroxide in 300ml of water in 500ml round bottom flask. When the KOH has dissolved add 10g of glucose to the flask and dissolve it by shaking. Add 6-8 drops of methylene blue indicator to the flask and swirl it. Allow the flask to rest untill the solution becomes colourless.<br>
Give the flask one or two shakes. The blue colour will reappear and then slowly fade. The regeneration and fading of blue colour maybe repeated a number of times by shaking the flask and allowing it to rest.
<br>'''Discussion'''<br>
Methylene blue indicator is blue in the oxidized form and colourless in the reduced form. It is reduced to the colourless methylene white by alkaline glucose. Shaking the flask dissolves oxygen in the flask and the dye is oxidized back to the blue form.
=Coloured Fountain=
<br>'''Materials'''<br>
500ml round bottom flask, 300ml water, 5-6 drops methyl red indicator, a long glass tubewith anozzle at one end, one holed rubber cork, conc.HCl, 2-3gof sodium bicarbonate.
<br>'''Procedure'''<br>
Take 300ml of water in the round bottom flask and add one test tube of conc.HCl and 5-6 drops of methyl red indicator and shake well. Fit the flask with cork carrying a long glass tube with the nozzle at the open end.<br>
Pack 2-3g of sodium bicarbonate in a filter paper or tissue paper, tie it with a thread with a loose knot and place in just above the solution in the flask passing the free end of the thread outside the flask through the cork. Cover the flask so that only the thred and glass tube visible to the audience.<br>
Ask the inaugurator to pull the thread gently so that the sodium bicarbonate packet detaches and falls into the acid. Within few seconds red coloured fountain emerges out of the nozzle.<br>
<br>'''Discussion'''<br>
Sodium bicarbonate as it comes into contact with the acid liberates carbon dioxide. The pressure built up pushes the water from the flask in the form of afountain.
=Funny liquids=
<br>'''Materials'''<br>
25ml carbon tetrachloride, 2-3 crystals iodine, copper sulphate solution(0.1g of salt dissolved in 25 ml of water) ,25ml benzene, 100ml measuring jar ,glass rod.<br>
<br>'''Procedure'''<br>
Place 25ml of carbon tetrachloride in the measuring jar. Add 2-3 crystals of iodine and shake to get a pink colour. Ask the audience what is the resulting colour when pink is mixed with blue. Pour copper sulphate solution into the jar and show the distinct pink and blue layers. Slowly introduce benzene into jar and exhibit the third seperate colourless upper layer. Using a glass rod try to mix the solutions by stirring. The layers remain as they are. Now closing the mouth of the jar with your palm give a vigorous shaking to the jar.Allow the solutions to settle. Exhibit only two layers-pink and blue.<br>
<br>'''Discussion'''<br>
Copper sulphate solution is immiscible with carbon tetrachloride and the two form seperate layers. Similarly benzene and copper sulphate are immiscible;benzene being lighter forms the upper layer.on vigorous shaking benzene dissolves in carbon tetrachloride and the colourless layer dissappers.<br>
=Colour bands=
<br>'''Materials'''<br>
Honey, liquid soap(green), water coloured by adding a rystal of KMnO4, vegetable oil, alcohol coloured by adding food colour.<br>
<br>'''Procedure'''<br>
In a tall glass jar or measuring cylinder pour directly about 10 ml of honey( do not pour from the sides). Above the layer of the honey slowly introduce about 10ml of coloured liquid soap. Next introduce pink color by adding coloured water. Similarly introduce vegetable oil and coloured alcohol.
Exhibit the five different bands of colourswhich do not mix with one another.<br>
=Magic fire=
<br>'''Materials'''<br>
candle, potassium chlorate 1g, sugar 2g , conc.H2SO4 ,glass rod.
<br>'''Procedure'''<br>
The foot of the wick is made a little cup shaped by previous burning. In this cup place a mixture of one gram of potassium chlorate and two grams of sugar. Dip the tip of a glass rod in conc.H2SO4 and bring it in contact with the wick of the candle. The candle catches fire instantly.
<br>'''Discussion'''<br>
Potassium chlorate exothermically oxidizes sugar in the presence of conc.H2SO4 and the heat produced is sufficient to light the candle.
=Fire writing.=
<br>'''Materials'''<br>
White sheet of paper, sodium nitrate solution ( dissolve 2g of the salt in about 20ml ofwater), glass rod, splinter or agarbatti stick.
<br>'''Procedure'''<br>
Write the word on the white paper using sodium nitrate solution with the help of a glass rod. (there should be continuity from the first letter to the last) Allow the paper to dry. The writing is almost invisible. Hang the paper in front and using a glowing splinter or glowing agarabatti set the fire to the begining of first letter. The sparkling fire continues till the last letter.
<br>'''Discussion'''<br>
Sodium nitrate is an oxidizing agent. As it decomposes giving oxygen the reaction ccontinous along the writing of sodium nitrate.
=Dancing sodium and blushing water=
<br>'''Materials'''<br>
Sodium piece, glass trough, phenopthalein.
<br>'''Procedure'''<br>
Cut a small piece of sodium. Dry it between the folds of filter paper. Using a clean spatula drop the piece of sodium into the glass trough containing water and a few drops of phenopthlein. Sodium runs around in the water with hissing sound gradually dissapperaing itself. Meanwhile the solution in the trough turns pink in colour.
<br>'''Discussion'''<br>
Sodiumreacts with water readily liberating hydrogen. Hydrogen as it comes out pushes the sodium and sets it in a random motion. Sodium hydroxide formed during the reaction renders the solution pink in the presence of phenopthalein.
=Magic Milk=
<br>'''Materials'''<br>
A clean plate, milk about 100ml, food colours( As many as youwant), dish detergent, a cotton swab.
<br>'''Procedure'''<br>
ut milk into the plate so that it covers the entire plate. Place a few drops of food colours around the milk in different places.<br>
Dip a cotton swab( earbud) in dish detergent.<br> Touch the milk with the dish detergent swab at the center. The food colour will start to swirl and move in different directions giving a colourful art work.<br>
<br>'''Discussion'''<br>
he dish detergent reduces the surface tension of water which allows the food colour to spread around the milk.
=Disappearing beakers=
<br>'''Materials'''<br>
Beakers 250ml,100ml, 50ml, 20ml, carbon tetra chloride 100ml, benzene 100ml.
<br>'''Procedure'''<br>
Place the small beaker into a big beaker. 20ml beaker in 50ml,50ml beaker in 100ml and 100ml beaker in 250ml. The beakers will be visible with definete boundaries. Pour a mixture of 100ml of carbon tetrachloride and 100ml of benzene into the250ml beaker untill the liquid level crosses the 100ml beaker upper rim. Hold the big beaker in front of the audience. The small beakers look to have dissappeared.
<br>'''Discussion'''<br>
Mixture of carbon tetrachloride and benzene has the same refractive index as that of glass and te ray of light passing through the beakers donot suffer refraction and hence the beakers become invisible.
=Fire ball in hand=
<br>'''Materials'''<br>
Roll a piece of cotton cloth into a ball. Using a string tighten the ball. Soak the ball with lighter fuel. Set fire to the ball and keep rolling into your palm or transfer from one palm to the other.
=Burning bubbles=
Take soap water in a cup and pass butane gas ( lightergas or LPG)into the solution to produce bubbles. Using a lighter set fire to the bubbles an enjoy the byrning bubbles.
=Fire Flare=
<br>'''Materials'''<br>
Fuming nitric acid 5ml., turpentine 2ml, china dish, beaker 250ml.
<br>'''Procedure'''<br>
Pour 5ml of uming nitric acid into the china dish and place the dish at the bottom of the beaker. Using a pipette or a narrow glass tube add turpentine on the acid dro by drop. As each drop falls into the acid it flare up and burns with a large flame, forming a cloud of soot.
<br>'''Discussion'''<br>
Fuming nitric acid is a powerful oxidizing agent. It oxidizes the hydrocarbons of the turpentine. The heat produced burns the turpentine.
=Green fire=
In a glass bowl take about 1g of boric acid (boric powder) and add one test tube of methanol ( methyl alcohol). Set the fire to the alcohol and watch the beauty of green flame.
=Inflate a ballon=
<br>'''Materials'''<br>
Ballon, a plastic bottle,dil HCl, sodium bicarbonate.
<br>'''Procedure'''<br>
Add about 100ml of dil HCl to the bottle.Take about 10 to 15gms of sodium bicarbonate in ballon.Now attach the mouth of the ballon to the mouth of bottle without allowing the sodium bicarbonate to fall into the bottle.Then infront of the audience show the ballon inflating by mixing sodium bicarbonate with dil HCl.
<br>'''Discussion'''<br>
When sodium bicarbonate is mixed with dil HCl CO2 is released which inflates the ballon.
=Hibiscus magic=
Take a white paper and fold into 2 equal parts.To one part rub with citric acid and dry it. Then using hibiscus flowers rub the both sides of the paper. The part with citric acid colour chages and the other part the colour do not change. Here the hibiscus flower acts as an indicator.
=Al Foil and Sodium Hydroxide=
Take a small piece of Al foil and add 3-5 pallets of Sodium Hydroxide pallets into it.Then slowly add 2-3 drops. Alluminium reacts with the sodium hydroxide and slowly the foil burns.
=Cloud in the Bottle=
Take a plastic bottle and light a match stick near the mouth. Extinguish the fire and then fill the smoke inside the bottle by compressing and releasing.Add the cap and then show the cloud of smoke.
=Rotating Candle=
Take a candle and insert a nail in between the candle and hang the candle using two tumblers. Now lighten the candle on both sides one after another. After a few seconds the candle starts moving ups and down and then slowly starts rotating.
=Magnet=
Take a new iron nail. Wrap a copper wire around nail and connect the two ends of the nail to the two poles of the battery. Now the iron nail acts as a magnet. It can be shown by bringing some iron fillings near to this.
=Pepper magic=
Take a small glass bowl and add little water. Add small amount of pepper powder at the center. Then dip your finger in soap solution and keep it over the water where pepper powder was poured. The pepper powder starts to move to the sides of the bowl by showing they hate the soap particles.
=Water jet=
Take a plastic straw and insert a small plastic stick in the centre. Now using a knife or blade cut the straw half way on both sides at equal distance from the centre. Now bend the straw in opposite side of the cut portion so that it touches the stick that is passs through the centre. Using cello tape make it stic to the stick. Now dip this straw water jet in water taken in a beaker and rotate usin your hand. The water starts sprinling around.
=To show the magnetic lines=
Place a bar magnet on the table wrapped with paper. Slowly pour iron fillings around the magnet. Slowly agitate the table. Beautiful magnetic lines can be seen.
=Egg magic=
Prepare a concentrated solution of NaCl. Take it in a 100ml beaker. In another beaker take water. Now take a raw egg and dip in water. It sinks. Take it out and place it in salt solution it flaots.The reason is because of differnce in density.
=Removing the coin=
Take two match sticks. Arrange them in such a way that their lighting portion should face upwards, one stick straight and another one errect touching the straight one. Below the errct one place a rupee coin well before. Now the glow the stick, the stick which is erret start moving up in air and the coin can be easily removed.
=Dispersion of light=
Take a glass trough filled with water.place a plane mirror in a slanted position so that the sun light falls on it. The sun light should fall on that portion of the mirror which is inside the water. Focus a beautiful rainbow on the wall. Here the water and mirror acts as a prism.
=References=
್ರFuntastic science experiments by Ronald Saldana <ಬ್ರ್br>
್ರ್ರyou tube -easy home science experiments by appu series.
