Aquatic Field Investigation
Materials and Methods 3
Air and Water Temperature


At this station your team will take air and water temperature measurements and learn what these measurements indicate about your aquatic site. Water temperature affects the ability of oxygen and salt to stay dissolved in water. Water temperatures greater than 20 degrees C (about 66 degrees F) do not contain as much dissolved oxygen as those below 20 degrees C. For salt content, the pattern is similar - as the temperature increases from 15 degrees to 30 degrees C (about 57 degrees to 84 degrees F), the salinity decreases. Air temperature is also an important characteristic of an aquatic site, because it gives scientists an insight regarding weather factors which will eventually increase or decrease the water temperature.

Materials

For the Pre-Field station:

For the field station:

Methods

Pre-Field Experiment:

  1. Hold the thermometer in the air until you can take a steady temperature reading. Record the results in your JASON Journal.
  2. Hold the thermometer in the cup of hot water until you can take a steady temperature reading. Record the results in your JASON Journal.
  3. Hold the thermometer in the cup of cold water until you can take a steady temperature reading. Record the results in your JASON Journal.

In the field, you will consider these readings along with measurements taken from other stations to determine the ability of your aquatic site to support life.

Field Experiment

  1. Hold the thermometer in the air until you can take a steady temperature reading. Record the reading on Master 4a.
  2. Hold the thermometer in the water until you can take a steady temperature reading. Record the reading on Master 4a.
  3. If you want to get a water temperature reading at a deeper spot, you can modify your thermometer as follows: Cut a piece of fishing line several meters long. About 15 cm (6 in) from one end of the line, tie the fishing line around a small rock or large pebble. Then wrap a piece of duct tape around the line and rock to hold them in place. Now tie the thermometer to the very end of the line (15 cm from the rock). Also secure the thermometer with a piece of duct tape. Holding the opposite end of the line, cast the thermometer into the water. The rock will provide the weight necessary to submerge the thermometer. Keep the thermometer submerged for about as long as it took to obtain a steady reading in shallower water. Record the results on Master 4a.

Conclusions

After you have completed both the Pre-Field and Field Experiments, discuss the following questions within your research team and record your answers in your JASON Journal.
  1. How are water and air temperatures good indicators of a site's ability to support life? How would sites with colder water likely differ from those with warmer water?
  2. How does air temperature relate to water temperature?
  3. Think about some of the measurements you have taken at other stations at the aquatic site. How do air and water temperature relate to these other measurements?
  4. What new questions do you have about how air and water temperatures affect aquatic environments?
  5. Look for more answers to your questions in the JASON Online Systems, the library, and science textbooks.


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Gene Carl Feldman (gene@seawifs.gsfc.nasa.gov) (301) 286-9428
Todd Carlo Viola, JASON Foundation for Education (todd@jason.org)
Revised: 3 Nov 1995