Melting Ice and Sea Level Rise

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Objective

SWBAT design an experiment to model and measure impact of sea level rise from ice melt.

Big Idea

Students design an experiment to model and analyze the impact of melting ice on land and on water.

Getting Started

There are two warnings about melting ice and rising oceans: one is by land, the other, by sea. But it’s ice sheets on land, not icebergs in the ocean, that are the biggest contributors to sea level rise.

Land ice includes mountain glaciers and ice sheets, covering Greenland and Antarctica. These giant blocks of ice are melting and the water is flowing rapidly into the oceans. Think of it like adding water to an already full glass — it soon overflows. But melting sea ice behaves differently. Axel Schweiger is a researcher at the University of Washington.

PhotoSCHWEIGER: “Melting sea ice has no impact on sea level rise because it’s already floating in the ocean.”

Think of as like a glass of ice water. As it warms, the ice in the glass melts, but the total volume of water does not change. However, melting sea ice does contribute to climate change. That’s because white sea ice reflects the sun. So when it melts, the dark open ocean now absorbs sunlight and heats up, raising global temperatures, which in turn cause glaciers and ice sheets on land to melt further. Globally, sea levels have risen four to eight inches since the last century and will continue to rise as the ice melts, putting coastal communities worldwide at risk.

Reporting credits: David Appell and ChavoBart Digital Media.
Photo: The Antarctic Ice Sheet covers an area larger than the U.S. and Mexico combined. This photo shows Mt. Erebus rising above the ice-covered continent. (Ted Scambos & Rob Bauer) Courtesy of the National Snow and Ice Data Center, University of Colorado, Boulder.

In this lab, students explore this phenomena using a simple lab set up. 

Materials (for each group)

  • Two 1-Liter Beakers
  • Two 150-mL (milliliter) Beakers
  • Crushed Ice
  • Plastic wrap
  • Sand
  • Water
  • Graduated Cylinder or beaker for measuring out 300 mL of water
  • Ruler

Engage

10 minutes

I begin this class with a thought experiment by asking students to think about the following scenario, then write a response in their journals before turning and talking to a neighbor about their ideas. 

The Too-Full Glass of Water

Show the image below while you narrate the story:

"You place four ice cubes into a glass and fill it with cold tap water to the brim. Using an eyedropper or spoon, you add even more water to make the glass as full as possible. 

Predict what you think will happen as the ice melts. Will the glass overflow? Why or why not? Write down your prediction and explain your thinking. "

Explore

45 minutes

Method

  1. Label the one 1L beaker “Sea Ice” and a second 1L beaker “Land Ice”.
  2. Fill each of the 150 mL beakers with equal amounts of sand.
  3. Cover each sand-filled beaker with plastic wrap. Tape the bottom of the plastic wrap to secure it in place.
  4. Place a sand-filled beaker in each 1L beaker.
  5. Next, SLOWLY pour 300 mL of water into each of the 1L beakers. Be careful not to disturb the sand. 
  6. Measure and record this original level (depth) of water in each beaker and record in table.
  7. In “Sea Ice” beaker, add crushed ice cubes (3-4 ice cubes equiv.) to the water around the 150 mL beaker. This represents floating (sea) ice.
  8. In “Land Ice” beaker, place the same amount of crushed ice on top of the plastic wrap. This represents land ice.
  9. Place both 2L beakers outside or under a lamp.
  10. Check the water level and ice every ten minutes throughout the session and record your observations on the data table. Record remaining ice as a % of total ice. You start with 100%. 

Below is an image of the experimental set up. We were able to use snow in place of ice. 

 

In the image below you can see the results a student got using compacted snow. Notice the rate of melt of sea ice versus land ice and the corresponding ending water levels.

Explain

15 minutes

Wrap up this lesson by asking students to read and answer questions related to the reading. See the attached handout on melting ice. 

This reading helps to drive in home the change in glaciers and connect this melting ice to sea level rise. Since we are talking about the inputs and outputs of a system and the relationship of the parts to the outcomes, this is a great opportunity to have students build causal loop diagrams. 

Causal loop diagrams help students make connections between elements in a story and identify the relationships between each of the elements. 

I have included a link PBS Learning Media's page on Understanding Causal Loops, a great place to start learning the basics of Systems Thinking. 

I have students share out their causal loop diagrams with the class. In the image below, one of my students is sharing her diagram.

 

Below are images of student completed work: