Making wool thread
Wool is the hairy coat of animals such as sheep, goats, camels and llamas. Almost all the world’s wool (about 95%) comes from sheep. Sheep are sheared once or twice a year with special shears or electric clippers. Before going to the factory the wool is prepared: first it is sorted by quality, then teased loose and cleaned of bits of straw, then washed in hot water with soap and soda and dried. The clean wool is spun into thread. Wool keeps heat in well, so it is very good for winter clothes.
You need: 3 identical cups, warm (not hot) water, scraps of wool and cotton cloth, rubber bands, a clock. Steps: 1) An adult pours the same amount of warm water into each cup (not hot!). 2) Wrap the first cup in wool and the second in cotton and hold with rubber bands; leave the third bare. 3) After 20 minutes unwrap the cups, dip a finger into the water in each one and decide which stayed warmest. 4) Write the result: the wool-wrapped cup usually stays warmest. Safety: never use boiling water; only an adult pours the water.