Sugar Attracts Water, Soap Repels Water
You will need: Bowl of water, wooden matchstick, lump of sugar, soap.
It is interesting to see the differing actions of soap and sugar when they are allowed to touch the surface of a bowl of water.
Cut a wooden splinter (or match-stick) into small pieces and float them on the surface of the water. When a cube of sugar is placed in the center of the water (see Fig. 1) the pieces of wood are immediately attracted toward it. This does not occur because the sugar has suddenly developed any magnetic tendencies, but because the sugar is so porous that it draws water into itself. The pieces of wood can be seen moving toward the sugar on the small current which has been created.
If you replace the sugar with a small sliver of soap you will see the
reverse action. The soap gives off a slight, oily film which spreads quickly
outward from the point where the soap touches the water and weakens the surface
tension. The pieces of wood are similarly affected and their movement is also
outward and away from the piece of soap.
Children learn best through doing
Before children can understand a thing, they need experience: seeing, touching, hearing, tasting, smelling; choosing, arranging, putting things together, taking things apart. Experimenting with real things.
Old-time school teaching used only words and the teachers thought children knew something if they could repeat it. Now we know better. To reach practical understanding we do not need to use many words with young children.
Children are clever. They learn a lot, without being taught. The greatest skill - to be able to talk, to communicate is learnt outside school. In the classroom it's the children who need to talk the most. Unfortunately it is the teacher who does most of the talking!