SCIENCE WONDERS

INVISIBLE INK:

A simple chemical reaction makes invisible ink visible. Squeeze some juice from a fresh lemon, then write, then paint it on to a piece of while paper. When the juice dries, the marks are virtually invisible. To make them visible put the paper in an over 175 degrees centigrade for 10 minutes. How it works? The heat burns the chemical so its becomes visible.

TURN MILK INTO PLASTIC:

Many plastics are made from petroleum oil. Oil formed in the rocks over millions of years, from the bodies of billions of small creatures. You can make a similar plastic in a few minutes using milk, another organic(carbon containing) substances.
Warm some creamy milk in a saucepan. When it is just simmering, slowly stir in few teaspoons of vinegar. The acidic chemicals in the vinegar react with organic milk chemicals. Keep stirring cool and wash it under running water. You now have your own plastic, which you can bounce around or mould into shapes. (Wash 'plastic' in ta water leave plastic to dry-figure).

UN FREEZABLE WATER:

Pure water changes from a liquid to solid as its temperature falls below 0 degree centigrade. We call this freezing. But water that contains a dissolved chemical, such as salt, freezes at a lower temperature. You can make up-freezable water by dissolving as much salt as you can in cold tap water. Put this salt solution in one plastic container, and clean water in a similar container. Place them in the icebox or freezer. The pure water soon turns to solid ice. The salty water stays liquid for much longer. In very cold weather, salt is spread on roads. It dissolves in anywater there, to stop dangerous ice forming on the road surface. The water in an iceberg freezes at 0 degree d since it is made from rain water. Seawater freezes well below 0 degree centigrade, because of the salt dissolved in it.