Monday, June 18, 2012

Why Smoking Causes Cancer ?

                                          Tobacco smoke contain more than 60 carcinogenic compounds. 4000 individual substances identified in tobacco smoke, including carbon monoxide, hydrogen cyanide, ammonia and other toxic irritants. The main reason is tobacco contains nicotine. Nicotine is a additive content which alters brain functioning.

                                           Nicotine is naturally occurring liquid alkaloids. When a man smoke nicotine is absorbed through the skin and mucosal lining of the mouth and nose and by inhalation int he lungs. In the body it activate the same reward system as do other drugs such as cocaine. in the brain nicotine increases the level of neurotransmitter dopamine. so the brain responsible for feeling pleasure. People continue dosing themselves frequently throughout the day to maintain the pleasurable effects of nicotine and to prevent withdrawal symptoms.

Why do onion make you cry ?

                                   Onion cells contain some chemical compounds like sulfur. Cut the onion its cells are broken and the chemical compounds are released into the air. So that more volatile sulfured products are formed. Sulfured compounds react with the moisture in eyes forming sulfuric acid. Which produce a burning sensation. So that the tears comes out.

How To Avoid ?

  • Chop the onion under cold water. The volatile sulfured compounds will be released but then they react  with the water, instead of reaching your eyes.
  • You can freeze the onion for 10 minutes before cutting it. The cold temperature of the onion will slow down the chemical reaction which forms the volatile sulfured compounds.

How meals are cooked faster in a pressure cooker ?

                                         A pressure cooker is like a pot but with a more elaborated lid that seals the pot completely. Heat water inside the pot, it boils and the steam cannot escape.So it remains inside and the pressure is increases. Under pressure cooking temperature raise much higher than under normal condition. So the food is cooked much faster.

How Soap Clean ?

                           Substance which can be dissolved in water and others that cannot. For example water and oil. water and oil do not mix together. So we try to clean oil stain from a cloth or hand water is not enough. So we need a soap.
                           Soap is formed by a molecules of hydrophilic and hydrophobic. So that soap molecules act like a diplomat, and improving the relation ship between water and oil.

                    When soap is added to the water

  • The hydrophilic heads of molecules stay into the water.
  • The long hydrophobic chain join the oil.
                      Then they formed circular groups named micelles, with the oil material absorbed inside and trapped. An emulsion of oil in water is then formed after that the oil particles becomes suspended and dispersed into the water. Soap cleans by acting as an emulsifier. It allows oil and water to mix. So that oily grime can be removed during rinsing.

Tuesday, June 5, 2012

Thrust :

                  All aero planes with engines and all rockets depend on thrust. Thrust makes them move forward. They push large amount of air or other gases in one direction. This makes the aircraft fly in the other direction. Now you can see how thrust work in these experiments with balloons.

Things need :

o   Long balloon
o   Heavy paper
o   Tape
o   Felt-tipped pens

Uncontrolled flight :

   v  Use felt-tipped pen to decorate the balloon as an aero plane if you like. It is easier to draw on the   balloon if you blow it up first. Do not tie it shut. Tie it round a matchstick or a pencil.
   v  Cut wings from the heavy paper. Tape them to the Centre top of the plane.
   v  Remove the matchstick or pencil. Blow the balloon up as full as you can. Let it go. Thrust will make it fly around the room in a series of loops and turns until it runs out of air. 

Make the lemon peel dive :

Things need :

    §  Piece of balloon
    §  Lemon peel
    §  Broad mouthed bottle or rubber band
    §  Water

Instruction :

v  Fill the bottle with water till the brim.
v  Put a peel or lemon in the shape of a boat in water.
v  Stretch the piece of balloon on the mouth of the bottle and with the rubber band seal it in place on the mouth of the jar. The balloon should be slightly stretched. It should not sag.
v  Using you finger gently press down on the lid (balloon cover ) and the lemon peel will dive to the bottom of the jar.
v  Release you finger the lemon peel will return to the top of the jar.
Why ?
              The pressure exerted by hand squashes air bubbles in the lemon peel allowing the water. This makes the lemon peel heavy and sink. When the finger is released the air in the lemon peel expands and returns to the top.

Bring the balls together :

Things need :

   §  Ping pong balls
   §  Table
   §  Straw
Instruction :

            ·         Place the ping pong balls a short distance a part on a table.
            ·         Use the straw to blow air between them. The ball move towards each other.

Why ?
                   Air presses on all things. This is called air pressure. When you blow between the ping pong balls, you blow away the air that is between them. This means that air is no longer presses against one side of each ball. But air still presses against the other sides of the balls, and that air pressure pushes the ball together.

Make the paper rise :

Things need :

v  A piece of paper

Instruction :

  •    Hold a piece of paper by the corners of edge.
  •    Bring it up to your mouth. The paper will droop towards the floor.
  •    Blow gently across the top surface of the paper. Does the paper still droop.
  •    Take a deep breath and blow harder.
  •    The paper rise. Before you blow, the air on both the sides of the paper is still.

§                                                    The pressure is same on both the sides. When you blow over the upper surface, the pressure on the side is reduced. But the pressure underneath is the same as before. The higher pressure underneath forces the paper up. Blowing harder reduces the pressure on the upper surface even more.  This makes the paper rise even higher.

Why water won’t run through the bottle ?

Things need :

            ·         Glass jar with narrow neck
            ·         Funnel
            ·          plasticine
            ·         Screwer
            ·         Water

Instruction :

           *      Position a funnel in the neck of the jar.
           *      Seal it tightly with plasticine.
           *      Fill the funnel with water.

The water cannot flow into the jar. Now  make a hole in the plasticine , the water flow into the jar because the pressure is same inside and outside of the jar.

( i.e ) why you need to make a holes before you can pour liquid from a tin.

Make your own fossil :

Things needed :

             ·         Plasticine
             ·         2 paper cups
             ·         Plaster of paris
             ·         Water
             ·         An object that you would like to use as the fossilized impression

Instructions :

   v  Flatten a ball of plasticine until it is about 2 cm thick while making sure the top is smooth.
   v  Put the plasticine inside the paper cup with the smooth side facing up. Carefully press the object you want to fossilize into the plasticine until it is partially buried.
   v  Carefully remove the object from the plasticine. An impression of the object should be left behind.
   v  Pour half cup of plaster of paris and stir until the mixture is smooth.
   v  Leave it for around 2 minutes.
   v  When the mixture has thickened, pour it on top of the plasticine in the other cup. Leave the mixture until    the plaster has dried.
   v  When the plaster has fully dried, tear away the sides of the paper cup and take out the plasticine and plaster. Keep it in a warm dry place .

Effect of acid rain on rocks :

Things required :
  •   Plastic cup
  •  Vinegar
  •   Water
  •  Small piece of lime stone

How it’s react ?
 o   Take a plastic cup. Take half cup of vinegar. ( vinegar is an acid )
 o   Place a small piece of lime stone in the cup of vinegar.
 o   Allow it to soak for several days.
 o   Remove the lime stone and observe carefully.

Why ?
                 In nature when rain water combines with carbon dioxide in air or with carbon dioxide from decaying organic matter , carbonic acid is produced. When the acid flows through cracks in limestone, it chemically reacts with the rock forming dissolved calcium, which is carried away in water.



Effect of frost in rocks :

Things needed :
           *      Two paper cups
           *      Freezer
           *      Plaster of paris
           *      Water
           *      Scissors
           *      Butter knife

Ø  Take a cup of about 3 inches height.
Ø  Prepare plaster of paris in the cup.
Ø  Use the butter knife to cut a narrow one inch deep groove into the plaster of paris before it dries.
Ø  The grooves should not touch the edges of the container.
Ø  Allow it to dry completely.
Ø  Carefully tear the container away to reveal your block. Measure the size of the groove. Fill the groove with water and place the block in the freezer.
Ø  After the water has frozen, remove the block and record your observation. Allow the ice to melt and place it in the freezer again. Repeat this till the block brakes.

Make a sand stone :

Things needed :
v  Fine sand
v  Two paper cups
v  Water
v  Epsom salt
How to make ?
   v  Take a paper cup. Drop 1 inch of fine salt into it.
   v  Fill another cup with water  about 1 inch high.
   v  Add Epsom salt slowly with stirring still no more salt dissolves.
   v  Pour the Epsom salt solution over the sand in the cup. Stir well.
   v  Place the mixture in a place where it will dry.
   v  It will take few days to dry.
   v  When it is completely dry, take the paper cup away from the sand.