Melting Sea Ice and Sea Level

Engage

45 minutes

Engagement section is covered in Arctic Sea Ice Data.

Explore

45 minutes

Arrange students in pairs. Each pair of students needs the following materials:

• Water
• 1 clear plastic 6-8 oz. cup
• Permanent felt-tip marker or tape
• Ice cube

Instructions:
1. Pour warm water into the cup, so that the cup is about half full.
2. Add an ice cube to the cup and carefully mark the level of the water with a permanent marker or a piece of tape.
Ask students to predict what will happen to the water level in their cup as the ice cube (iceberg) melts, and to record this prediction in their science notebooks.
3. Let ice melt in the cup. Report changes in sea level in their cups.

While students are waiting for their ice to melt, they can cut and assemble the sea ice flip book.

If time, pace, and materials are not available, this activity can be demonstrated by the teacher.

Explain

20 minutes

Ask students if their predictions were correct. Ask for explanations for why the water level in the cup did not change. Ask students to reflect on the following questions in their science notebook: What does this experiment suggest might occur to the sea level if arctic sea ice continues to melt?

Ice is less dense than water. An ice cube floating in a glass of water displaces the same volume of water that it contains. So, if sea ice were to melt, the sea level would stay the same.

Extend

If you would like to further explore the concept of density, you can change this activity slightly. Use salty water in the cup, and melt a blue-colored ice cube in the water. The cold blue water from the ice cube will melt and form a distinct layer on top of the warmer, clear salt water, showing that even though it is much colder, it is less dense than the salt water.

Another option is to use warm fresh water in the cup, instead of salt water. The blue water from the ice cube will be more dense than the warmer water, so the blue water will sink to the bottom. It will gain heat energy as it sinks through the warmer water column, so as it moves along the bottom it will begin to rise.

Evaluate

This activity is followed by Temperature and Sea Level Rise.