GO IN DEPTH

Thermal Mass Lab

By Fred Bauder [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0), via Wikimedia Commons

Introduction

In this investigation, you will determine the best material to be used as a thermal mass in a passive solar home design.

Materials
Your lab group should test a material for its effectiveness as a thermal mass. You will need:

• Box with clear plastic cover
• Stop watch
• Thermometer
• Heat lamp or direct sunlight
• Thermal mass material assigned by your teacher
• Black or white construction paper assigned by your teacher

Procedure

1. Place the thermal mass material in the box and cover the box with plastic
2. Insert the thermometer through the hole in the top of the box so that the bulb of the thermometer is close to, but not touching, the thermal mass.
3. Record the initial temperature in the data table.
4. Place the box under the heat lamp, or in direct sunlight. Take the temperature every minute for 10 minutes. Record your observations in the data table.
5. Turn off the heat lamp or remove from the sunlight.
6. Record the temperature every minute for 10 minutes. Record your observations in the data table.

Data Table

Thermal Mass Material:

Color of Construction Paper:

Initial Temperature:

 Minutes 1 2 3 4 5 6 7 8 9 10 Lamp on temp. Lamp off temp.

Analysis

• Create a graph of your temperature data.
• After all data is entered, get a copy of the graph that shows all the materials tested by all the groups from the class data spreadsheet.
• Which material showed the fastest change in temperature? __________________
• Which material showed the slowest change in temperature? _________________
• Which material had the greatest range of temperature?______________________
• Which material had the least range of temperature? ________________________
• Did there seem to be a relationship between the color of materials and how well they absorbed and stored heat?

• Did there seem to be a relationship between the color of the construction paper and how well the materials absorbed and stored heat?

• Which material went through a phase change, and how did that seem to affect the temperature change during the test?

• When something melts, it absorbs energy called latent heat. When it freezes, it releases that latent heat. How can that concept be applied to a thermal mass for passive solar energy?

• Looking at the graphs, why do some materials experience more rapid temperature changes and a greater temperature range than others?

• Remember, the purpose of the solar mass is to absorb energy during the daytime and release that energy at night. Which material do you think would be the best thermal mass to use in a home and why?