Page 96 - ICSE Science 3 : E-book

ACTIVITY TIME

Soluble and Insoluble Substances in Water
Aim:
To understand which substance is soluble and insoluble in water
You Need:

Two beakers, water, a spoon, a spoonful of salt, a
spoonful of sand
What to Do:
• Pour water in both the beakers.
• Add a spoonful of salt in one beaker and sand
in another beaker and stir.

• Observe carefully if you can dissolve the two
substances in water.
Observation:
You will observe that salt dissolves completely in water while sand does not dissolve
and settles down at the bottom when left undisturbed.
Result:
Salt is a soluble substance while sand is insoluble. Insoluble substances will not dissolve
even in hot water.

Objects that Float and Sink in Water

Density of an object decides whether it will fl oat or sink in water. All objects
including water are made up of very tiny particles packed together. These tiny
particles are known as molecules. In some objects, the molecules are very tightly

packed whereas in others they are loosely packed. This forms the density of an
object. Objects with tightly packed molecules have higher density than water,

and so they sink in water. For example, stones, fruits, coins and paperclips sink in
water. Objects with loosely packed molecules have lower density than water, and
so they fl oat on water. For example, wooden logs, ice cubes, balloons and several

plastic objects fl oat on water.

Objects that sink in water Objects that fl oat on water

82