Support children to investigate how they can make ice melt.
Early Learning Goal links
Understanding the World ELG: Past and Present – Talk about the lives of the people around them and their roles in society;
Understanding the World ELG: People, Culture and Communities – Describe their immediate environment using knowledge from observation, discussion, stories, non-fiction texts and maps;
Understanding the World ELG: The Natural World – Understand some important processes and changes in the natural world around them, including the seasons and changing states of matter.
STEM vocabulary to introduce
Freezing, cold, solid, hard, melting, wet, dripping, smooth, shiny, white, crystals, see through, cloudy.
Before you start
Freeze water in your containers overnight. Remove the ice from the moulds and place on a tough spot or in a tray.
What to do
Step 1
Tell the children they are going to be glaciologists and look carefully or observe the ice.
You could ask:
What shape is the ice?
What colour is the ice?
Is it the same colour all over?
What can you see inside the ice?
What does the ice feel like?
Step 2
Provide the children with pipettes (or plastic straws) and a beaker of warm water mixed with food colouring. The colour helps the children see what the warm water is doing to the ice. Tell them that glaciologists are curious about what makes ice melt. Ask the children what they think or predict will happen when they drip warm water on the ice.
Ask the children to drip the water onto the ice and to observe what happens.
You could ask:
What has happened? What has changed?
What can you see in the bottom of the container?
Has all of the ice melted?
What does the ice look like now?
What can you see inside it?
What can you hear?
What do you think will happen next?
Step 3
Step 3: Now provide the children with some salt. You may want to give them this in a salt shaker or in a container with a spoon. Ask the children to sprinkle salt on to the ice and to observe what happens.
You could ask:
The questions from step 2 again and see if the answers have changed.
Which shapes are melting the quickest?
Do you think the salt is making them melt faster?
Other things to try
Leave the ice, pipettes, water and salt out for the children to investigate. Ask the children how long they think it will take the ice to melt.
Challenge the children to melt the ice as quickly as they can using the salt and warm water.
The science of melting
We have put together some useful information about the science of melting to accompany this activity. Don’t worry this is for your information only and to help you answer any questions children may have. We don’t expect you to explain this to the children in your setting!
How does water freeze?
Water is a molecule made up of two Hydrogen (H) atoms and one Oxygen (O) atom. Molecules are constantly moving because they have energy. In a liquid form, water molecules have more energy than in a solid. As the liquid cools down, the amount of energy is reduced, and the molecule movement slows down. When the water temperature reaches around 0°C, the molecules stick together and form a solid. This is ice.
Why does ice melt?
Ice melts when heat energy causes the molecules to move faster. If the temperature of the water rises above 0°C the movement of the molecules breaks the bonds between them to form liquid water.
Why does warm water make ice melt faster?
Warmer water contains more heat energy, causing the molecules to move faster and the bonds between molecules to be broken faster to form liquid water.
Why does salt make ice melt faster?
Salt lowers the freezing point of water. This is called “freezing point depression.” The salt makes it harder for the water molecules to bond together to form a solid.
Why does the surface of the ice melt faster?
During melting, the water molecules absorb heat energy. This heat is transferred from the water, air or object surrounding or touching the ice and is why an ice cube melts more quickly on the outside and retains its coldness and solidity longer at the centre.
What you’ll need
- Ice frozen in a variety of shapes and sizes- water balloons and plastic containers such as yoghurt pots make good larger moulds.
- Water
- A freezer
- Tough spot or tray
- Pipettes (or plastic straws if you don’t have any)
- Beakers of warm water coloured with food colouring
- Salt
- The geologist poster
Duration
10 minutes or so.
