Strand: Materials

Lesson: Dissolving Solids in Liquids

 
Aim/Objectives

To increase pupils' knowledge of solids, liquids, gases and their properties.
To experment dissolving substances in liquids.
To explore changes in substances through heating and cooling.

Materials Needed

Laptop
Projector
Screen
Speakers
C.D. Rom - Mad About Science 3 - Matter DK
Selection of materials - solids, liquids and gases for categorisation
Water
Containers
Substances eg sugar, salt, tea bags, curry powder sto dissolve in water

Content/Methodology

Introduction

Elicit what pupils already know about Solids, Liquids and Gases. Elicit properties of each, give examples and summarise in a table eg below.

 

 

Solids

Liquids

Gases

 

Properties

Fixed shape
Fixed size
Can not pour

Flows
Changes shape to fit shape of container

Flows

Spreads to fill space it occupies

 

Examples

 

Jug, brick, spoon, salt

Water, syrup, raindrop

Steam, air, perfume

Development

Set up laptop and data projector. Insert CD Rom and click on Al's Kitchen.
Select the following sections:

24: Does it dissolve in water - which materials dissolve or do not dissolve in water
25: Dissolving to the limit
27: Ice, water and steam - how do you turn water into a solid block of ice or cloud of steam?

Explore interactive games which ask children to:

Section 24: group materials (salt, brown sugar, sand, chalk powder, flour, brown rice, washing powder and tea leaves) into two categories - those which dissolve in water to make a solution and those which do not.

Section 25: find out how much of a substance can dissolve in water until the solution becomes saturated.

Section 27: identify heating and freezing processes - eg ice changes to a liquid when heated to 0 degrees Celcius, conversely it changes back to ice when temperature is lowered; a liquid changes to steam when it is boiled to 100 degrees Celcius and conversely changes back to a liquid when cooled.

Vocabulary includes: heats, cools, melts, freezes, evaporates, condenses

Children are asked a series of multiple choice questions on the above information.

Conclusion/Follow Up Activities

Experiments:
Dissolve a range of substances in water to see if they dissolve or not.
Observations made and recorded.

Click on pictures for results of experiments.

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