Contributed by: Louise Huffman, Director of Education and Outreach for the US Ice Drilling Program Office, Dartmouth College
When presenting to a large audience, or if you are looking for an easy hands-on activity to do with a classroom, this activity works well.
It is a common misconception with non-science audiences regardless of age, that ALL melting ice will raise sea level. This is a simple demonstration that can be used in almost any venue with almost any audience to demonstrate the difference between melting land-based ice (glaciers, ice sheets, etc.) and floating ice (sea ice, ice bergs, etc.). Audiences will consider how melting ice affects sea level by observing two models that are identical except for one factor: one will have ice on “land” and the other will have ice in the “sea.” Directions for using the activity as a demonstration can be found on the ANDRILL website.
If you have the opportunity to visit a classroom, this can easily become a hands-on activity that the students create by using two smaller sandwich-sized clear containers for each group of four students following the same directions in the link. Set-up this demo at the beginning of your presentation, have the audience predict the answer to the questions (how will melting land-based/floating ice affect sea level? Raise it? Lower it? Stay the same?) and then revisit the models at the end of your presentation to discuss the results.
Lessons learned from less-than-successful demos:
- Stack as much “land-based” ice as possible on the rocks not touching the water to be sure the melt water is enough to raise the “ocean” level noticeably.
- Be sure the lines drawn to mark ocean levels are drawn accurately and AFTER ice is added to the water
- Put as much “floating ice” in the “ocean” water as possible but be sure it is truly floating and not grounded to the bottom.
- If you have a short presentation and need the ice to melt quickly, place the containers near a window and/or add salt to the “ocean” water and “land” rocks and use small ice cubes or crushed ice. If you want it to melt slower (for example at a museum or all day event), use larger ice blocks and no salt.