成人快手

Watch: What is dissolving?

Learn about dissolving and mixing.

When you add some sugar to water and stir, what does the water taste like? Can you explain why?

Back to top

Dissolving

Circle character looking at a beaker of water heating.
Image caption,
Heat can help some substances dissolve faster in water. Salt, for example, will dissolve quicker in hot water than in cold water.

When a substance dissolves, it might look like it has disappeared, but in fact it has just mixed with the water to make a transparent (see-through) liquid called a solution.

Substances that dissolve in water are called soluble substances. When you mix sugar with water, the sugar dissolves to make a transparent solution. Salt is soluble in water too.

Substances that do not dissolve in water are called insoluble substances. When you mix sand or flour with water, they do not dissolve.

Circle character looking at a beaker of water heating.
Image caption,
Heat can help some substances dissolve faster in water. Salt, for example, will dissolve quicker in hot water than in cold water.

Watch: Solutions

Discover all about solutions.

Back to top

Investigate different substances

Tap on the different substances to find out what happens when you add them to water.

Back to top

Watch: Key learning

Here's what you needed to know about dissolving and evaporation.

Back to top

Activity 1: Fill in the gaps

Back to top

Activity 2: Quiz

Back to top

Activity 3: Investigating dissolving

You may need a pen and pencil for this activity.

Try stirring small amounts of some solid substances into different samples of water to see if they are soluble. What substances could you try?

Back to top

More on Properties and change of materials

Find out more by working through a topic