Explore: Just add water

Water has no smell, no taste, and no colour. Pure water has nothing else added to it.

But, it is difficult to get completely pure water – there will almost always be other substances mixed in. Even the most pure water will contain dissolved gases from the air. If water smells, tastes odd, or has some colour, water has impurities in it!

Water easily becomes a mixture. In fact, water has the amazing ability to dissolve most substances. Water is called a universal solvent (able to dissolve or make other substances seem to disappear). The substance that is added to the water and seems to disappear is called a solute.

In a hot chocolate drink, the powdered hot chocolate mix is the solute, and the hot water is the solvent.

In the washing machine, the laundry detergent is the solute, and the water is the solvent.

When a substance dissolves in water, its particles become separated completely and mixed with the particles of water. We call this type of mixture a solution because we cannot see the separate particles of solute and solvent.

In this activity, you will test various solutes to see if they will form solutions. A water-soluble substance is something that will dissolve in water. If it does not dissolve, we say that it is insoluble. Your first step in learning about mixtures is to see what kinds of mixtures can be formed using water.

Did you know?


Water is known as the universal solvent because it dissolves more substances than any other known liquid does.


More than half of the world’s plants and animals live in water. Without water there would be no life on Earth.

What substances are soluble in water?


Materials

  • large bowl or cup
  • water
  • salt
  • sugar
  • oil
  • sand
  • flour
  • vinegar
  • juice
  • food colouring
  • butter or margarine
  • two substances of your choice
  • teaspoon

  Notebook

Click here to download the instructions for this activity. Save this file to your Chemistry Notebook.

  Video

For instructions on how to complete this experiment, watch the ADLC Digital Lesson on Solubility.

ADLC - Elementary Science Solubility

  Check Your Answers

Once you have completed this activity, check your answers below.

Substance

Observations

Soluble

 Insoluble

Salt Disappears into the water

 
Sugar Disappears into the water

 
Oil Floats on top of the water but does not mix
 
Sand Sinks to the bottom
 
Flour Forms clumps that float on the water
 
Vinegar Disappears into the water

 
Juice Mixes with the water and becomes lighter colour
Water changes to the colour of the juice

 
Food Colouring
Mixes with the water and becomes lighter colour
Water changes colour

 
Butter or Margarine
Forms clumps that float on the water
 

1. Answers will vary.

2. salt, sugar, vinegar, juice, and food colouring

3. oil, sand, flour, butter/margarine


Chemistry Connection

The chemical formula for water is H20. This means that water is made up of one oxygen particle attached to two hydrogen particles. The hydrogen in water creates something called hydrogen bonds, which are extra strong bonds between water particles. These hydrogen bonds are responsible for water’s many unique properties such as the following:

  • the ability to dissolve so many substances
  • the high boiling point (100o C)
  • surface tension

Click here to watch the BrainPop: Water video to learn more about water! Try the quiz at the end to check your understanding.

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