Materials Affect the Rate of Heat Transfer - Experimental Design
Lesson 5 of 6
Objective: SWBAT compare different materials to determine which ones are better at preventing heat transfer.
Students have learned a lot about heat, heat transfer and thermodynamics. Working as scientists they collected data and evaluated data from their experiments. Now they will collect data specifically to evaluate materials for penguin homes. This lesson provides students an opportunity to apply what they learned in a real world context.
According to CNN Antarctica experienced a record high temperature of 63.5 degrees Fahrenheit on March 24, 2015. Student must determine which materials to use to build penguin homes.
Students must find a way to construct igloos for the Antarctic penguins that will reduce the transfer of heat. An experiment must be designed to test available materials. (MS-PS3-4 Plan an investigation to determine the relationships among the energy transferred, the type of matter, the mass, and the change in the average kinetic energy of the particles as measured by the temperature of the sample.) (MS-PS3-3 Apply scientific principles to design, construct, and test a device that either minimizes or maximizes thermal energy transfer.) (SP3 Planning and carrying out investigations.)
As part of the process, students will be able to identify three methods of heat transfer. (MS-PS4-2 Develop and use a model to describe that waves are reflected, absorbed, or transmitted through various materials.)
Students gather scientific information that they will apply in the next lesson (Penguin Homes) where they construct prototypes of igloos to be tested using "ice penguins" to determine if their design protects the penguins from being overheated. (SP1 Asking questions and defining problems) (SP2 Developing and using models) (SP4 Analyzing and interpreting data) (SP6 Constructing Explanations and designing solutions) (SP7 Engaging in argument from evidence) (SP8 Obtaining, evaluating and communicating information)
The construction of the testing stations is the longest timeline for teacher preparation for this lesson. The testing station is a black box. It can be a storage container or simply a box painted black. The inside of the box is lined with heavy duty aluminum foil on the sides. The black floor is not covered. Place four shop lamps around the outside of the box. Position them so they shine on the foil and the floor of the testing station. Place thermometers at the testing stations. Quick read digital thermometers are the best. A wet sponge should be at each station. Students will use the sponge to cool the thermometer after each test in the testing station.
The materials provided for student testing should be cut into 3" x 3" squares and placed into a container or baggie to be given to each test group. Suggested materials are: construction paper: black, green, pink and white, foam sheets: black, green, pink and white, felt fabric: black, green, pink, and white, bubble wrap, aluminum foil, and Mylar. Also include the cotton balls and craft sticks. Cotton balls and craft sticks are used to elevate the thermometer so students are measuring air temperature and not the temperature of the floor of the testing station.
An easy-to-print complete materials list is available in the resource section.
This lesson was adapted from Save the Penguins ©2009 Christine G. Schnittka, Ph.D. in cooperation with the Virginia Middle School, Engineering Education Initiative (updated version 5-13-13)
Students in Action
We begin the lesson by stating the problem - penguins are suffering from a general warming trend. Their habitats in the Antarctic are disappearing as the climate warms and the ice melts. Without our help they will not survive. We must build suitable housing to protect them. Before we can design homes for penguins, we have to find out which materials will prevent heat transfer into the penguin home. Available materials are expensive so accurate testing is of the utmost importance.
Three experimental stations have been setup for student testing. Each station has a hot box, heat lamp, thermometers and a cup of water. The water will be used to cool the thermometer after testing.
Students are given a bag of sample supplies that may be used to build the penguin home they design for to keep the penguin shaped ice cube from melting. The material costs are high so determining which materials will prevent heat transfer the best is critical.
- Cotton balls
- Craft sticks
- 3" x 3" Construction paper: black, green, pink and white
- 3" x 3" Foam sheets: black, green, pink and white
- 3" x 3" Felt fabric: black, green, pink, and white
- 3" x 3" Bubble wrap
- 3" x 3" Aluminum foil
- 3" x 3" Mylar
I explain to students that they will use the cotton balls and craft sticks to build a platform for their penguin home. The penguin home will be placed on the platform and the thermometer will be place under the thermometer to check for changes in temperature.
A Sample Test Station
The test station is an empty printer paper box. The bottom is painted black. I used tempera paints from the local hobby store. The sides are covered with foil. The heat lamp has a 60 watt incandescent bulb. It is hard to locate 100 watt incandescent bulbs. Because the 60 watt bulb generates less heat than the 100 watt bulb, we increased the testing time from 1 to 3 minutes. Note the platforms for the testing materials are made from cotton balls and wooden craft sticks.
The testing station allows for all three type of heat transfer to occur. We review each of these big ideas as a class.
- Radiation - radiation is the heat from the light along with the reflection of the light off the foil sides of the test station.
- Conduction - bottom of the test station box is painted black and will heat up from the radiation from the light. The heat of the floor will warm the air under the penguin home.
- Convection - the heated air radiated from the light will rise in the test station, cool and sink. We talked about convection currents in the lesson - Convection Currents as an earth science lesson.
Data Collection Student Sample
Students used prior knowledge to determine that they minimally wanted the top color to be a lighter color and did not test the darker green and black as the top color for testing. This document is a sample of one groups average test results.
In the following video, I explain why my students did not use the lesson sheet for data collection but instead designed their own.
Connecting the Learning
At the conclusion of data collection, I asked students to consider the following questions as they designed their penguin homes. Students discussed the answers with their lesson partner as they began to consider possible designs.
- Which materials performed the best?
- Why do you think these materials worked better than others?
- What combination of materials worked the best?
- Why do you think these combinations worked better than others?
The materials provided for penguin home construction are constraints for this engineering challenge.
I remind students that their criteria for success is to design the best home to keep the penguins cool for the least amount of money.