Dissolve or not?

Test which things dissolve in water and which do not.

In your book, Our Wondrous World (Chapter 2), there is a simple activity. Take two clear glasses of water. Add a spoonful of sugar to one and a spoonful of cooking oil to the other. Stir both well.

The sugar dissolves: it mixes into the water completely and disappears from sight, so the water still looks clear. The cooking oil does not dissolve: it stays separate from the water and you can still see it.

So some things dissolve in water and some do not. Salt dissolves in water too, like sugar. Sand does not dissolve, like oil.

This is why the Godavari warns us: harmful things like chemicals or dirty soapy water can hide in a river. Even when the water looks clean, it might still carry things that can hurt living beings.

Some things, like sugar, dissolve in water and cannot be seen, while others, like cooking oil, do not dissolve; so water that looks clean can still carry harmful things such as chemicals or soapy water.

Practise this lesson

Questions that get harder as you improve, a Tutor that helps without giving the answer away, and progress you can see. Free for every learner.

Try it now Sign up free I have an account

No account, no email address. Opens the real product.