Things Around Us
How things work
Work out what makes one thing spin and another wobble, run a float-and-sink test properly, and see why the same piece of foil can do both.
Meera spun a coin on the table and watched it go. Then she and Dhruv tried a bangle, a pencil, a stone and an eraser, and found that some things spin beautifully and some hardly spin. Then it rained, they made paper boats, and a new question started: some of the boats sat on the water and some flipped straight over.
Guess first, then look
The chapter does not let you drop a thing into water and simply watch. It asks you to write your guess down first, and to say why you think so, and to drop it after that. Doing it in that order is what turns splashing about into an experiment, because a guess you have written down can be proved wrong.
Have a play
The same square of aluminium foil, three times over, in three different shapes.
Tap any part of the picture.
Worked example
An iron nail sinks and a leaf floats. Does that mean heavy things sink and light things float?
Check the rule against the two things that suggested it. A nail is heavy and sinks; a leaf is light and floats. So far, so good.
This is how a wrong rule gets born — it fits the first two cases perfectly.
Try it together
Let us look closely at a spinning coin, together.
Spin one on a table and watch it right to the end, rather than looking away once it is going.
1.The coin spins fast, then slower, then slower still. What does it come to in the end?
Have a go
Your turn. The class made boats and compared them. What does the chapter say they found?
Ready to practise?
Eight questions on what you have just read. Nothing is timed, and you can play as many times as you like.