This is a STEM lesson emphasizing science, technology and math. The science deals with the relationship between the Fahrenheit and Celsius temperature scales. The technology used is the littleBits temperature sensor. The math portion of the learning experience includes graphing points on the coordinate plane, and plotting the equation of a straight line on the coordinate plane. During the process the students will be engaged in inquiry and critical thinking.

**Duration: 1 45-minute class**

**GRADE LEVEL**

Middle School (ages 11-13)

High School (ages 14-17)

**DIFFICULTY**

Intermediate

**SUBJECT**

Physical Science

Engineering

**MODULES & ACCESSORIES USED (6)**

power (1)

mounting boards (1)

temperature sensor (1)

number (1)

wire (2)

**LESSON GUIDE**

**STEP 1 : Introduction**

This lesson will give students practice in several things:

1. Using the equation F = 9/5C + 32 to compute values for F° for several different C°.

2. Plotting the equation relating C° and F° on an xy chart.

3. Observing the y-intercept and relating its value to the equation.

4. Computing the slope of the equation’s straight line and relating this value to the equation.

5. Using the littleBits temperature sensor to collect several data pairs (C°,F°) over a Celsius range from approximately 3°C to 35°C.

6. Graphing (C°,F°) coordinates obtained from a littleBits temperature sensor on an xy chart.

7. Hypothesizing explanations for why the littleBits data does not follow the equation perfectly.

**STEP 2 : Construct the littleBits circuit for collecting the data.**

The image below shows a circuit that the student’s can use to collect the temperature data. As shown in the figure, it consists of power, wire, temperature sensor, wire, and number bits, in that order. The circuit is mounted to a mounting board to provide more mobility for the circuit. The two wires are optional, but help to keep adjacent bits from warming the sensor on the temperature sensor bit. The Number bit mode is set to values so that it will display temperatures in degrees, either F° or C°, depending on the setting on the temperature sensor.

**STEP 3 : The Accompanying PDF File**

The accompanying Temperature_Experiment.pdf file contains pages that may be duplicated for students to record their data and construct the graphs.

Page 1 contains two tables, with the top table for computing values of F° from C° using the equation. The students can then plot these points on the chart on page 2. For teacher reference, page 3 contains a graph with the equation already plotted. The y-intercept (F°-intercept) is 32°F, the freezing/melting point of water, corresponding to 0°C. The slope of the line is 1.8 = 9/5 F° per C° and tells us that each Celsius degree corresponds to 1.8 Fahrenheit degrees.

For teacher reference, page 4 contains data obtained from the littleBits temperature sensor. Page 5 contains both sensor data and the line for the equation relating F° and C°.

The table at the bottom of page 1 of the pdf file can be used by the students as they collect (C°,F°) data pairs using the littleBits temperature sensor.

**STEP 4 : Collecting Temperature Sensor (C°,F°) Data Pairs**

Students will need to collect data for a temperature range from about 3°C to 35°C. The data can be recorded onto a copy of the table at the bottom of page 1 on the accompanying pdf file. One way to get the higher temperatures in this range is to place the sensor in direct sunlight for several minutes. Then readings can be made periodically as the sensor cools down to ambient room temperature. Similarly, the sensor could be placed in a refrigerator for several minutes to cool down. Then readings can be made periodically as the sensor warms back up to ambient room temperature.

**STEP 5 : Plotting the temperature Sensor (C°,F°) Data**

After collecting the temperature (C°,F°) data pairs, the students can then plot these pairs on the chart. They should then be encouraged to suggestion explanations as to why the points do not fall perfectly on the line for the equation relating Fahrenheit and Celsius temperatures.