| Do you know the weather picture? |
| you will need: coloured picture, blotting paper,water, some cobalt chloride and cooking salt. Do you remember the weather pictures, the brightly coloured pictures on which the blue turns pink in damp weather? Pictures like these can be made quite easily. Dissolve in some water two teaspoonfuls of cobalt chloride and one of cooking salt. In the solution soak a piece of new, white bloting paper. While the paper is damp it is pink. Let it dry in the sunshine or near the fire and it changes to blue. Now you must make a coloured picture, for example a seaside, or a mountain scene. Over the of the sky stick you piece of blotting paper. In dry weather the sky is bright blue, but when damp weather is coming we are warned in good time because the sky turns pink. |
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| Boiling water in a.. paper basin! You will need: sheet of stiff paper, 4 paper clips, water, flame. Don't you believe it is possible to boil water in a paper basin over a flame? You expect the paper to catch fire from the heat of the flame?Oh, come... Nothing is more convincing than doing the experiment. From a piece of stiff paper make a small dish . Fix the corners securely with paper clips. Then fill the paper dish with waterand put it on the gas. Take care that the flame does not reach that part of the paper above the water, and that the corners are not in the flame. After a while the water will start to boil without the paper getting burnt. During the heating the water takes away the heatwhich the paper receives form the flame, and the paper never gets hotter than 212° Fahrenheit; the boiling point of water. This temperature is very much lower than at which paper catches fire. |