Activity 3 (Explore): Why Are Sea Levels Rising?
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In this activity, students design and run experiments to determine whether sea ice or land ice is having a bigger effect on sea level rise. They then use this information to draw conclusions about which is more responsible for the sunny day flooding from their original phenomenon.
Activity Objectives & Materials
Approximate Time: 1-2 class periods (60-90 minutes)
Students will design and conduct experiments to determine the effect of melting land and sea ice on sea level change.
Materials (see activity for details on these materials)
Computer & projector
Ice, Water, Measuring cups, Containers, Rulers, Clay or other materials to make “land”
Scale (optional to weigh ice)
Heat lamp (optional)
What is Causing the Ocean to Rise?
DCI: ESS 3.C: Human Impacts on Earth Systems
SEP: Planning & Carrying Out Investigations
CCC: Cause & Effect
Name as many places as you can think of where there is water (in any form) on Earth.
Possible answers: lakes, rivers, the ocean, the atmosphere, ice, snow, the ground, etc.
Have students share when they are done with their lists, but don’t discuss further (they will use these lists shortly)
1. Frame the Activity
During our last activity, we learned that sea level rise is causing the sunny day flooding. The next question we have to answer then, is what is causing the sea level rise? During today’s activity, we’re going to do an experiment to help figure out why the ocean is rising. If students asked any questions in Activity 1 related to sea level rise (or where the water is coming from), tell students they they’ll be investigating this question today.
2. Where is the Water Coming From?
Have students consider the lists they made during their warmup, and ask what percentage of the world’s water is in the ocean. They will likely know that most of the water is in the ocean, but they may be surprised how high the percentage is (97%). Show them the pie chart below:
Next ask them where the 3% is. They will likely say things like the lakes, rivers, the air, etc. If they don’t mention it, ask about water in another form. See if students recognize that some water is frozen. What percentage of the 3% is frozen as ice? Show students the pie chart below, which breaks up the 3%:
Students may be surprised to find that more than 2/3 of the freshwater on the planet (2% of the total) is frozen as ice in glaciers and ice caps (make sure students know what a glacier is). 1% of the total is in the ground, and only a tiny fraction (about 0.007%) is in lakes, rivers, and swamps.
Ask students: if the sea level is rising, where do they think the water is coming from? They will likely say it is coming from the melting ice. Tell them that during their experiment today, they are going to investigate how melting ice can affect sea levels.
Melting ice vs. thermal expansion: In this activity, students learn about how melting land ice affect sea level rise. Thermal expansion (when water expands as it is heated) also plays a major role in causing sea level rise. How much each of these factors affects sea level rise is still debated today. While there is not space in this activity to introduce students to thermal expansion in detail, it is worth bringing it up when time permits. See this article for more information on the debate and see this graph for additional information on how much each contributes to sea level rise.
3. Land Ice vs. Sea Ice
Hand out the “What is Causing the Ocean to Rise?” sheet to students. Show students these two pictures and ask them what the difference is in what they see (the pictures are also on their sheets)
There are several differences, but the important one to help students see is that in the picture on the left, the ice is on land, and the picture on the right, the ice is floating in the ocean. Once picture (on the left) is Antarctica, and the other is the Arctic Ocean. Have students label the left picture “land ice” and the right picture “sea ice.” Ask them where land ice is found (mountains and Antarctica) and sea ice (the Arctic Ocean). Ask students if they think land ice melting or sea ice melting is doing more to cause sea level rise. Have them write this research question on their sheets.
4. Design the Experiment
Materials: This activity can be done in small groups (recommended) or as a whole group. If it is done as a whole group, use a larger container to make it easier for all students to see.
This experiment requires a very simple setup, so rather than tell students what to do, have them design their own experiments given the materials you have. In general, student groups will need:
2 identical containers (one each for sea and land ice) approximately 6” x 6”
Something to make land out of (blocks of wood, clay, a jar, etc.
Something to measure height (ex. a ruler)
Heat lamp (optional – see timing tip below in "Run the Experiment")
Tell students what materials you have available (having additional materials will give them more flexibility in their designs).
Form students into groups and have them brainstorm ways they could test whether sea ice or land ice will make the ocean level rise higher. When they have an idea, they should share it with you for approval. You may also choose to have students share ideas as a whole group. If students are stuck, consider asking questions such as:
What will you need in order to compare sea ice vs. land ice?
How can you simulate land ice?
How can you simulate the ocean?
How will you measure sea level rise?
Have students write down the materials they will use for their experiments, and draw their designs in the boxes at the bottom of their data sheets.
Differentiation: Depending on students’ level of experience designing their own experiments, they may have an easier or harder time getting started. You may want to brainstorm together as a class before having student groups work on their own.
Teacher Tip: The amount of ice in each container needs to be the same. If you don’t have ice cubes that you can count, suggest to students that they use a scale to weight out equal amounts of ice.
5. Variables, Controls, and Data Gathering
On the back of their sheets, have students consider what they are changing between the two setups (independent variable), what they are measuring (dependent variable) and what needs to be the same for both of their setups (controls). In general, these will be the same for all groups:
Independent variable: ice on land vs. ice in water
Dependent variable: the height of the water
Controls: same container, same amount of ice, same amount of water
Also have students describe how they will measure the water rise, and what units they will use.
6. Write a Hypothesis
Have students write a hypothesis about whether they think the land ice or the sea ice will make the water rise more. Encourage them to think about why the land or sea ice will make the water rise more.
7. Build the Setups
When you are confident that students understand what they are doing, have them build their setups. As they are building, make sure they are measuring the amounts of ice and water they put into each container to be sure they are equal. Also check that the ice in the “sea ice” container is floating (not sitting on the bottom), and the land ice is above the water level.
As groups finish building, make sure they measure the height of the water as quickly as possible before the ice starts melting.
Teacher Tip: If you are short on materials, pair up groups that have similar designs so that one builds the sea ice setup and one builds the land ice. Just make sure they work together to ensure the amount of ice and water is the same.
8. Run the Experiment
If you are having students leave the experiment overnight, then make sure you have at least 1-2 measurements before they leave class. If you are using a heat lamp, you may want students to take measurements at regular intervals. The data sheet on their handout is flexible to accommodate various methods.
Timing Tip: It is possible to do this experiment in a shorter time period if you set up a heat lamp or put experiments in a sunny location where the ice will melt more quickly. This will also prevent evaporation from being a variable.
9. Data Analysis
When students have collected all their data, have them analyze the data by determining which water level rose more and by how much. You may choose to have students graph their data (especially if they took data at multiple points), but since the most consequential data is the beginning and ending points, it is not necessary.
10. Sensemaking Discussion
As a whole group, have student groups share their results. Did everyone get the same result? Why or why not? Use discussion techniques to have students consider why the water level rose more in the “land ice” than the “sea ice.” While they do not need to understand the physics of buoyancy, they should understand that the ice on land was added to the water level, making it go up. The ice in the water was already there, so when it melted, it didn’t make the water go up at all.
11. Check In With Questions
Go back to students’ question board from Activity 1. Are they able to answer any of the questions they asked? If so, take a moment to acknowledge this and make note of what they’ve figured out.
12. Conclusions (Formative Assessment)
Have students complete the conclusions section of their experiment handout, including why the water rose more in one container than the other, and which kind of ice melting they think is causing the sunny day flooding from their original phenomenon.
Experiment Reflection: If you have time, have students reflect on their experience of designing and running their own experiments. What did they like? What was frustrating? What would they do differently next time? This opportunity to reflect on the process of science is useful in helping students learn to think like scientists.