How Warming Water Causes Sea Level Rise

It’s not required, but you can use a heating pad or lamp in this activity. To avoid burns, have an adult help you with the use of heating pads or lamps. DO NOT attempt this activity without adult supervision.

Completely fill the bottle with water to the rim. If possible, use a bottle made with thick, sturdy plastic. It's OK if some water spills out. Just have a towel ready to clean it up. You can use food coloring to make the water more visible. If you don’t have food coloring, use something else like tea to color the water. Colored water isn’t required.

Grab your clay and wrap it around the straw, being careful not to pinch the straw closed with the clay. Leave 2-3 inches (5-8 cm) of straw above and below the clay and be sure to close any gaps between the straw and the clay so no water can leak out.

If you want to add a thermometer, you can:

• Apply a stick-on thermometer to the side of the bottle that will face away from the heat source.
• Or poke a small hole in the clay with the thermometer probe. The thermometer should not interfere with the position of the straw.

Insert the straw into the water bottle. Have a towel ready to clean up any spills. The straw should extend down about 2-3 inches into the bottle. Using the clay, putty or another sealant, seal the top of the bottle. There are several ways you can do this:

• Plug up the bottle opening using clay wrapped around the straw.
• Wrap the clay around the opening of the bottle and cover the threads.

No matter how you do it, make sure no water leaks out of the top of the bottle. You should see some water in the straw near the top of the clay.

Place the water bottle in the place where you plan to apply heat from a lamp, the Sun or another heat source. Use the marking pen to mark a line on the straw to indicate the base, or zero-level, of the water. Because moving and squeezing the bottle can alter your measurements, avoid moving or handling the bottle once the line is marked.

Direct a heat source at the bottle or place the bottle in direct sunlight. Because some heat sources apply heat with different intensities, you'll want to keep checking the water bottle to make sure the heat isn’t damaging it.

At regular intervals – every minute or five minutes – measure and record the water level in millimeters, starting from the zero-level mark drawn on the straw. Make note of what’s happening. For each measurement, you should align the "0" mark on the ruler to the zero-level mark you made in Step 4. If you're using a thermometer, also record the temperature at these intervals.

Note: The time it takes to notice a change in temperature and water height may vary depending on the heat source you use and the size of your water bottle.

Write a description of what you observed in the straw. Graph your measurements on paper or using spreadsheet software.

What happened to the water level as heat energy was added? How does this relate to increasing global temperatures and sea level rise?