Idiom of the Day
wind up (something) or wind (something) up
to tighten the spring of a machine or clock to make it work
Every night before he goes to bed my grandfather winds up his alarm clock.
Science Experiments Ideas
A piece of sulphur is ignited in a jam jar. Since a pungent vapour
is produced, you should do the experiment out of doors. Hold
a red rose in the jar. The colour of the flower becomes visibly
paler until it is white.
When sulphur is burned, sulphur dioxide is formed. As well as its germicidal action in sterilisation,
the gas has a bleaching effect, and the dye of the flower is destroyed by it. Sulphur dioxide also
destroys the chlorophyll of plants, which explains their poor growth in industrial areas, where the gas
pollutes the air.