Objective: Children will perform an experiment to determine which substance will work best to melt ice.‹ Return to Theme
What You Will Need
Note: This is a two-part lesson to be conducted over 2 days.
- 7 oz. plastic cups – 1 per child
- Small classroom objects, such as marbles, dice, small plastic toys – 1 per child
- Large trays – 2
- Pitcher or ladle – for pouring water
- Proximity to a freezer (or outside space if overnight temperatures will dip below 32° F)
- Coarse salt – 1 shaker per every 2 children
- Cold water – ½ cup per child
- Warm water – ½ cup per child
- Pipettes – 1 per child
- Plastic plates – 1 per child
What To Do
- Tell the children they will be performing an experiment to explore what works best to melt ice.
- Distribute cups to the children.
- Assist the children with pouring water into the cups, making them two-thirds full.
- Allow the children to select one of the small classroom objects and drop it in their cup.
- Place the cups on a tray and transfer the cups to the freezer, or if outside temperatures are predicted to dip below 32° F overnight, place the tray of cups outside.
- Take the cups from the freezer, or bring them inside and remove the ice blocks from the cups.
- Distribute one ice block on a plate to each child.
- Distribute pipettes, salt, and cups of water to the children.
- Instruct the children to use the pipettes and the cold water to try to melt the ice. Give them a few minutes and discuss if it is working.
- Next, have the children try using the pipettes with the warm water to melt the ice. Give them a few minutes and discuss if it worked better than the cold water.
- Last, have the children sprinkle some salt on their ice cubes. Allow the salt to sit for a few minutes and discuss if it worked better than the warm water or the cold water.
- Allow the children to use the substance they felt worked best until the toy can be removed from the ice.
- Discuss the children’s findings.
Guiding Student Inquiry
- Describe what will happen to the objects in the water.
- Tell me what happened to the water.
- Describe what the ice feels like.
- Explain how we could get the objects out of the ice.
- Explain which substance you think was most helpful in melting the ice.
Explore, Extend & Integrate
- You could allow the children to add a few drops of food coloring to color the water before freezing. Or add liquid watercolors a few minutes after adding the salt, as this can show more clearly how the salt has affected the ice.
- Freeze additional cups of water and place them in the discovery area with pipettes, warm water, cold water, salt, and small wooden mallets for further exploration.
- If the outside temperature is not cold enough to freeze the water, you could place a container of water outside and then discuss why it did not freeze but the cups in the freezer did freeze.
Check for Children’s Understanding
- Could children explain that the water froze and became ice?
- Could children explain how they got the objects out of the ice?
- Could children explain that the salt was the most helpful with the melting process?
Did You Know?
The word water usually refers to water in its liquid state. Water in its solid state is frozen and is more commonly known as ice. Water can also be a gas in the form of steam or water vapor. Water freezes at temperatures below 32 degrees Fahrenheit. Ice begins to melt when the temperature around it begins to rise above 32 degrees Fahrenheit. Unlike most substances, water expands when it freezes. This is why an ice cube will take up more space than it did as the liquid water it was made from.
In winter, many regions experience very cold temperatures. Any water on surfaces such as roads and sidewalks will freeze and become hazardous to drive or walk on. In some of these regions, salt is frequently used to help melt the ice. When salt is added to a block of ice, the area of ice immediately surrounding the grain of salt begins to melt. The melting process spreads out from that point. This is because salt lowers the freezing point of water.
- ice – frozen, solid water.
- warm – having some heat; not cold.
- melt – to change from a solid to a liquid through heat.
- freeze – to make into ice or become solid from cold temperatures.
- liquid – a form of matter that can flow and is neither a solid or a gas. Water is the most common liquid on Earth.
- solid – having a firm shape or form that can be measured.
- To assure that the children will be able to see the effect of the salt more dramatically, use warm water that is not much above room temperature.
- Use plates that are large enough to accommodate the amount of water that will dissolve from the ice blocks.
- Kosher or rock salt produces better results due to the larger grains of salt. These larger grains burrow further into the ice, producing big rivers down the side of the ice blocks.
- Ice (Weather) by Helen Frost
- Ice is Nice!: All About the North and South Poles by Bonnie Worth
- Freezing and Melting (First Step Nonfiction) by Robin Nelson
- Ice Maker, Ice Breaker (Reading Essentials: Exploring Science) by Brian Birchall
Content provided by:
Common Core State
These lessons are aligned with the Common Core State Standards ("CCSS"). The CCSS provide a consistent, clear understanding of the concepts and skills children are expected to learn and guide teachers to provide their students with opportunities to gain these important skills and foundational knowledge.