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Title
Activity: Sea Level and Gravitational Flow
NGSS Science and Engineering Practices
NGSS Crosscutting Concepts
NGSS Disciplinary Core Ideas
Materials
- Transparent plastic cup
- Nail or sharp pencil
- Masking tape
- Transparent plastic shoe box
- Ruler
- Food coloring
- Coins or other weights
Procedure
Image caption
Fig. 3.21. Setup for the Sea Level and Gravitational Flow activity
Image copyright and source
- Predict what will happen when a cup with a hole in the side is filled with water to a level above the level of water in a box (Fig. 3.21 A). Record your predictions.
- Carefully punch a hole in the plastic cup as shown in Fig. 3.21 A. The height of the hole should be about halfway up the side of the cup.
- Test the system by carrying out the following steps:
- Cover the hole with masking tape. Leave an unattached flap so that the tape can be easily removed.
- Fill the box two-thirds full tap water.
- Place coins in the bottom of the cup so it does not float.
- Fill the cup with colored water to a level a centimeter or more above the level in the box.
- Pull off the masking tape and sketch your observations. Observe for at least two minutes.
- Set up the system as shown in Fig. 3.21 B. Repeat the procedure step 2, except fill the cup so that the water level is a centimeter below the water level in the box.
Activity Questions
- Explain why the water flows as it does in systems A and B.
- How might the conditions shown in systems A and B be produced in the ocean?
- The Atlantic ocean basin has a lower average sea level than the Pacific ocean basin.
- Which system is modeling the Atlantic ocean basin? The Pacific ocean basin?
- The Atlantic and Pacific ocean basins meet near Antarctica. How do you think the water is flowing in this area? (Bonus: Research the water flow around Antarctica to further your knowledge about this area of the world ocean.)
- The major ocean basins on Earth have large circulation cells called gyres. Gyres pile water in the center of their circulation.
- Which system is modeling a gyre?
- How does a gyre affect water flow?
Exploring Our Fluid Earth, a product of the Curriculum Research & Development Group (CRDG), College of Education. University of Hawaii, 2011. This document may be freely reproduced and distributed for non-profit educational purposes.