Lesson: Our Town

Prerequisites:

Thermometer Reading
North, South, East, West
Map Reading
Reflectivity and Absorption

Objectives:

This lesson uses and/or introduces new tools in geography, math, and science to make observations and draw conclusions on the local temperature variations in your area.

Materials:

A large map of your town which covers an area large enough to include all of the student's addresses.
One thermometer for each student or as many as possible (see Resources for possible sources of thermometers)
Graph Paper
A large sheet of paper or poster board
Assorted colored stick-on stars
Red, White, and Blue construction paper

Introduction:

Explain to the students that they will be taking thermometers home this evening to record the temperature of the air in their backyard. "You will all be taking the temperature at your home at exactly 7 PM tonight." Some questions to stimulate thought:

Any guesses as to what the temperature will be tonight?
Do you think you will all record the same temperature or different temperatures? Why?
If there are different temperatures recorded, will the warmer ones be on one side of town and the colder ones be on another or will they be mixed up? Why?
Are there any reasons why the temperature where I live will be different than where you live?

Body:

Hang the map of your town in a place in the classroom where it can remain relatively undisturbed for a week or so, yet is accessible by the students. On the large sheet of paper(s) or poster board list the student's names down the left side with room for an address column and a temperature observation column. Place a colored star next to each name on the list using as many different colors as possible.

* Mrs. Floyd        | 105 South State Street     |  59

* Sally Fields      | 620 Elm Street             |  58

* Bobby Reynolds    | 511 Maple Street           |  59

* Sue Blue          | 100 Magnolia Lane          |  61

etc...

Start the lesson by asking the students to print their address with marker in the address column next to their name on the poster board. Next, have the student find the location of their home on the large map one student at a time, with the help of the class. The teacher may help or may feel it is necessary to have this part of the lesson prepared beforehand if no map skills have been taught. This section may be difficult and tedious so it can be done in several smaller sessions spanning several days if desired. Once a student has found his/her location, he/she should put a colored star on the map matching the color of the star on the name board. It may be a good idea to have the student put his/her initials next to the star to make it easier to locate each address later.

Before the rest of the lesson can be done, the students must record the air temperature at their home. Pick a day, preferably when the evening promises to be clear, to send a thermometer and instructions home with each student. The following day when the students return with their temperature observations, they can each record their temperature next to their name and address on the poster board. Explain that the students are making a table of the temperature observations. A table is another name for a list of items, such as temperatures, names, and addresses.

Max/Min/Range:

Ask the students: "Did everyone have the same air temperature at home last night?" Tell the students that you are interested in finding the range of the temperatures in your town last night. To do this you need to know the maximum (highest) temperature and the minimum (lowest) temperature in town. The maximum temperature is the highest temperature on the list or table. No other temperatures will be greater than the maximum. Have the students find the maximum temperature on the list. Write the temperature on the chalkboard. The minimum temperature is the lowest temperature on the list. No other temperatures will be less than the minimum temperature. Have the students find the minimum temperature on the list. Write the temperature on the chalkboard. If this exercise proves difficult it may help to sort the list of air temperatures on the chalkboard from least to greatest with the help of the students.

OPTIONAL: Explain to the students that "in our town the air temperatures changed from (maximum, e.g. 59) in one part of town to (minumum, e.g. 39) in another part of town." We call this change from one area to another the "range of air temperatures." We can make a measure of the range of air temperatures by taking the difference between the maximum and the minimum air temperatures. As a class, subtract the minimum from the maximum in a conventional manner or by counting up from the minimum to the maximum while holding up fingers. The number of fingers up when the maximum is reached represents the range of the air temperatures. The larger the change or difference between the maximum and minimum, the larger the range in air temperatures. The smaller the change or difference between the maximum and minimum, the smaller the range in air temperatures.

Graphing:

Note: The following procedure can be time-consuming. It is advisable to have other activities available for the students to do while others are graphing their data.

Make a large graph template on the chalkboard or a large piece of poster board with air temperatures labelled on the vertical axis and student's names labelled on the horizontal axis:

      60 ____________________________________________________
           |       |       |       |       |       |       |
      59 __|_______|_______|_______|_______|_______|_______|_
           |       |       |       |       |       |       |
      58 __|_______|_______|_______|_______|_______|_______|_
           |       |       |       |       |       |       |
      57 __|_______|_______|_______|_______|_______|_______|_
           |       |       |       |       |       |       |
      56 __|_______|_______|_______|_______|_______|_______|_
           |       |       |       |       |       |       |
      55 __|_______|_______|_______|_______|_______|_______|_
           |       |       |       |       |       |       |
      54 __|_______|_______|_______|_______|_______|_______|_
           |       |       |       |       |       |       |
        Mrs. F.  Sally   Bobby   Sue     Fred     Sam    Tina

Model how temperatures are plotted on the graph by putting an X on the temperature that you observed. Read your temperature from off the observation posterboard and count up from the bottom of the graph until you reach the value which corresponds to your observation. Put a bold X at the intersection of the lines for your temperature observation and your name.

Have each student come to the graph, read their observation from the observation board, count up from the bottom of the graph and put a bold X over the correct temperature. When the graph is full, explain to the students that this is another way to represent the information on the observation board. To demonstrate this: turn the observation board so that the students cannot see it. Show the students that you can find your temperature from the graph by searching the horizontal axis for your name, follow the vertical axis up until you reach your bold X, follow the horizontal axis to the left to read the temperature. Have a few students come to the graph, find their names, follow up to the X, left to their temperature observation, and read their temperature to the class. Finally, have each student find the temperature observations for another student using the graph. Position the observation posterboard so that the rest of the class can check that the process is working yet the student at the graph cannot see it.

Comparing Temperatures:

Sometime before the start of this part of the lesson, calculate the average of the temperature observations (round to the nearest degree). Explain to the students that you are going to draw a line through the middle of the temperatures on the graph. Draw a thick horizontal line across your graph through the average temperature. Your graph should look something like this now:

      60 ____________________________________________________
           |       |       |       |       |       |       |
      59 __X_______|_______|_______|_______|_______|_______|_
           |       |       |       |       |       |       |
      58 __|_______|_______|_______|_______|_______X_______|_
           |       |       |       |       |       |       |
      57 ==|=======|=======X=======|=======X=======|=======|= 
           |       |       |       |       |       |       |
      56 __|_______X_______|_______|_______|_______|_______X_
           |       |       |       |       |       |       |
      55 __|_______|_______|_______X_______|_______|_______|_
           |       |       |       |       |       |       |
      54 __|_______|_______|_______|_______|_______|_______|_
           |       |       |       |       |       |       |
        Mrs. F.  Sally   Bobby   Sue     Fred     Sam    Tina

Explain that we are going to compare the temperatures to the middle line temperature. Some temperatures will be above this line, some temperatures will be below this line. Tell whether your temperature is above or below the middle line and by how many degrees. Count from the line up or down to your observation to get the number of degrees away from the line. Ask a number of students to do the same thing with their observations. Ask: "Whose air temperature is the farthest away from the line? How far away is it? Whose air temperature is the farthest away and warmer than the line? How far? Whose air temperature is the farthest away and colder than the line? How far? Are there any observations that are exactly line? Whose?"

Mapping and Data Visualization:

Explain to the students that you are going to try to determine which parts of town were warmer than the middle temperature line on our graph, and which parts were colder than the middle temperature line on our graph, on the night they took their observations. Ask each student to get some red construction paper if their observation was warmer than the line, blue construction paper if their observation was colder than the line, and white construction paper if their temperature was exactly on the line. Each student will cut a circle from their colored paper (2-6 inches, depending on the size of your town map). With a piece of tape, have the students place their colored circle on top of the star marking their address on the town map. The circles may overlap some.

When all the circles have been placed, ask the class to look at the map and try to determine if there are any areas which have more red than blue and any areas with more blue than red. Ask: "Was the area of our town with more red than blue warmer or colder than the surrounding area? Was the area of our town with more blue than red warmer or colder than the surrounding area? Can you think of any reason why one area of our town might be warmer than the other? Colder?"

Physical characteristics to watch for:

Elevation Changes: If you have hills or mountains in your area, the higher elevation areas may cool off faster in the evening.
Bodies of Water: If you have a decent size body of water near your town, the locations nearest the water may have their temperatures modified to be closer to the water temperature than surrounding areas.
Urban Heat Island Effect: Urban areas tend to be significantly warmer in the evening than rural areas because asphalt, bricks, concrete, etc. tend to absorb and retain heat more than surrounding areas.

Try to determine if any of the above may be relevant in your observed temperature pattern. If they are, propose the theory to the students and ask the students for their input as to any further experiments you might be able to perform to prove your theory. For example, if the central part of town has many red circles and the outskirts of town has many blue dots, you can explain the Urban Heat Island Effect to the students and review the lesson Reflectivity and Absorption. You may want to follow-up with an experiment in which you take temperature measurements over vegetation covered surfaces and over asphalt covered surfaces. If you have a body of water near you and you believe it may be influencing your evening temperatures in some way, you may suggest that the class somehow obtain the water temperature to test your theory. Even if the initial theory is suspect, proceed with the follow-up experiments keeping in mind that fostering scientific inquiry rather than the search for correct answers is the ultimate goal.

Conclusion :

Review with the class the three ways you looked at the temperatures you observed: table of observations, graph, and map. Ask the students to name their favorite. Why? What can the graph show that the table couldn't? Is it easier to find the maximum and minimum temperature from the table or from the graph? Can you think of other numbers for which a graph might be useful? What can the map show that the graph couldn't? Was it easier to see what areas where warmer and what areas where colder than the middle line temperature from the map or from the graph? Can you think of other numbers that would be useful to put on a map?

Vocabulary Words:

Maximum
Minimum
Range
Table
Graph

Evaluation:

Make up a list of air temperatures or have the students take another reading on another evening. From this new list of temperatures have the students find the maximum, minimum and range (optional) of the air temperatures.
Students can graph the observations in the list above on a prepared graph template.
Students can reconstruct the observed list of temperatures for each student using only the graph the class made.

Followup Lessons:

none

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