When Things Heat Up
To relate the physical and chemical properties of water to a water pollution issue.
In this exercise, students will measure the temperature and dissolved oxygen (DO) of a stream (or use their findings from the activity What’s in the Water?) and discuss what this information can tell us about possible pollution problems.
See discussion questions for additional background information and some leading questions to help guide discussions about the relationship between dissolved oxygen and temperature.
Note: This lesson plan is designed to follow the activity What’s in the Water? where students measure several abiotic factors in a stream, or the lesson can be conducted as a stand alone.
The lesson is designed in four parts:
- A classroom activity that helps students understand what they will be measuring and why;
- a field activity where the students explore a water body and collect water-quality data and other information (see tips on preparing for a water related activity to have a safe and meaningful experience);
- follow up STEM activities, discussion, data analysis, presentation of results
- and watershed connections.
1. Ask the students to list all the abiotic factors they can think of in an aquatic
system (e.g., solar radiation, physical structure of the stream or lake, surrounding landscape,
weather, and the properties of water itself).
2. Tell them they will be testing two of these factors that relate specifically to the water – dissolved oxygen (DO) and temperature.
3. Define each of these factors, talk about why these factors are important in an aquatic ecosystem, what can naturally influence these factors, and also what humans can do to influence these factors.
4. Explain to the students that they will be going to a stream (or other waterbody) to measure DO and temperature. Demonstrate how each test will be conducted in the field.
The following videos demonstrate how each test is conducted. dissolved oxygen and temperature.
You can also let the students try out each test, using tap water or other water that you've brought to the classroom.
NOTE: If you have already done the activity What’s in the Water? skip to field activity step five
Prepare for Field Activity:
Proper preparation, before entering the field, is important to class safety. Follow the links below for tips for thorough preparation.
1. Set up a station for each factor (DO and temperature). You may want to have multiple
stations for each factor so your students can work in smaller groups.
Note: Many teachers have an adult or older student volunteer at each station.
At each station, provide:
2. Divide the students into groups. Provide each group with clipboards, pencils, and student worksheets. Explain to the students that each group will start at a different station and rotate so each group will measure both factors.
5. Have the students compare their results to the state standards for water quality (found on the student worksheet) and determine if the water is in compliance with state standards.
6. If the results are in violation of the state standards, have the students hypothesize what may have caused this. Alternatively, give the students the following hypothetical situation and again have them hypothesize what may be causing the problem.
“You have returned to the same stream site to test the temperature and DO again. This
time your data show that the temperature is 20° C and your DO level is 4 ppm.” What
may have happened to change the results? (Summer versus winter time temperatures, loss of canopy cover, low flows, thermal source,
pooled or widened stream).
For more information, see the discussion questions for this activity and the discussion questions for the activity What’s in the Water?
After sampling, it is beneficial for the students to view and graph the data in order to understand the activity they have just completed. Some helpful ways to assist students in a better understanding are:
1. Use your data to create graphs and comparisons. You can view examples of some graphed data and sample data sets here.
- Compare results from different water sources or different locations within a water body.
- Compare samples from the same station on multiple dates or throughout the day.
- Compare results with samples that have been modified. For example, room temperature
water vs. stream water.
- Compare results from stream water with tap water, bottled water, or salt water (e.g., from the Great Salt Lake).
2. Compare your results to results collected by others.
- Go to Utah Water Watch's online database to find results from Citizen Monitors.
- Other online databases are available at : Bear River Watershed Information System or iUtah's online database.
- Contact USU Water Quality Extension (email@example.com or 435-797-2580) for help accessing other water quality data.
3. Discuss what the results mean. (See the discussion questions for this exercise, and for temperature, dissolved oxygen).
- Utah's Water Quality Standards or guidance are indicated on the field sheets.
- Learn about the "beneficial use designations" of the stream you are monitoring and what your water measurements mean
- Discuss what activities might affect the measurements you made. For example, loss
of shade along a stream leads to more heating from the sun.
4. Have students research DO concentration of water at different elevations, temperatures, during different seasons, salinity levels, etc.
Curriculum and Teacher Materials
Core Alignments by Grade:
Materials and Worksheets:
For Proper preparation:
Worksheets and More: