Explain: What will the students and teacher do so students have opportunities to clarify their ideas, reach a conclusion or generalization, and communicate what they know to others?
1. After the construction is completed, it's time to get a base reading of how well the houses are insulated as is. These readings are important for us to be able to see the impact of the insulation, which will be added in the next steps. Before testing:
- Introduce the tools that will be used: lamp, thermometers, iPad or other tablet.
- Have students practice reading the temperature in Celsius instead of Fahrenheit. Explain that Celsius is the unit used globally in the field of science.
- Be sure the students are familiar with the use of the iPads for the thermal imaging pictures. This can be achieved by using the filter offered in the "Photo Booth" application (preinstalled on iPads) or through a third party app, which can be found for free on the app store.
- Make sure that the students understand the light bulb is being used to represent a heater in their model homes and it will get very hot! Note that the thermometers could get hot to the touch as well.
2. In order to test the houses, you will need to set up your light bulb on a table and place the house over the light bulb. Explain the students that the light bulb will act as their house's heater. It is highly recommended that you use a 40-60 watt MAX incandescent light bulb as it will produce more heat than a compact-fluorescent bulb. Anything over 60 watts will get far too hot and cause the tape and straws to melt and fail.
3. You will want to have multiple thermometers in order to calculate an average temperature from inside the house, as well as multiple thermometers resting on roof of the house (on the outside). Before testing, use all of the thermometers to calculate an average of the room temperature of your class. Model how to take the temperature from four different thermometers in the room. Then model how to find the average room temperature by adding the four temperatures and dividing by four. Have the students create a table in their notebooks for recording this information.
4. Provide students with copies of the Data Log (attached) and go over the directions for collecting the data.
5. Note: In order to achieve the most controlled results, do not turn on the light bulb until you are ready to begin your timer. Go over the following steps for conducting the experiment:
- Step One: Place the interior thermometers around the light bulb and play around with the configuration of the thermometers until you find the best placement that allows the thermometers to be completely inside the house but still at the bottom, or "floor," of the house. Record the initial temperature.
- Step Two: Place the thermometers on the roof of the house as close to the middle as you can for the best results. Record the initial temperature.
- Step Three: Leave the light on and the house and the thermometers untouched for five minutes. You may choose to shorten or lengthen this time as you see fit. *Know that the longer you leave the light on, the hotter it will get. Be prepared to smell a faint heating of the plastics in the house, but do not be alarmed unless you see visible smoke. No part of the house should ever come in contact with the light bulb while it is on to avoid risks.
- Step Four: During the five minute period, allow students to use iPads or other tablet devices to take pictures of their house. There are a number of free apps that offer thermal-like or infrared-like filters for the camera. These filters will allow the students to see where light, or "heat," is escaping their homes. These are the spots that they will want to consider insulating in the next steps.
- Step Five: Once the time is up, quickly read the temperatures on the roof and in the interior. For safety, it is recommended that the teacher be the only one that touches the light bulb and thermometers after each test to avoid burns.
6. Repeat these steps for each house/team. For the most accurate results, allow for the thermometers to reach room temperature and the light bulb to be cool to the touch before each test.
7. Once the teams are completed with their initial test, have them discuss any problem areas they might have with their homes. Have them analyze the data at their tables. Ask: "Were the temperatures hotter on the inside or on the roof of your house?" "Why do you think that is?" "What can you conclude about the way heat travels?" You want them to see that heat rises and while there may be cracks or holes on the sides of the house, with most of the heat was going up towards the roof. Have them respond in their journals to the question on the Data Log. Discuss the difference between their observations and the inferences they are making about what happened.
8. Allow the students to compare their data with the other teams. You can do this by allowing them to move around the room freely or by making new groups. Try selecting one member from each team and have them form a discussion group. Disperse all of the students into the same type of groups. Before returning to their engineering teams, have students write a brief summary about the results shared with them in their discussion group. Have them answer the following questions: "What was different about the results of the other teams?" "Why do you think that happened?" "Could there be a flaw in the results?"
9. After the test, have students observe different types of insulation used in actual constructions of houses. Explain that aluminum insulation is much like tin foil and fibrous insulation like cotton balls and newspaper are used in walls and the ceilings of all buildings. Allow the students to handle the three types of insulation and describe their physical properties using their senses in their notebooks. Each group should then compare notes and compile their observations in their notebooks and form a group hypothesis as to which materials will work the best from these choices: aluminum foil, cotton balls, or newspaper.
10. Finally, have them write their conclusions in their notebooks and submit their choice of material, then plan the steps that need to be taken in order to insulate their houses.
Elaborate: What will the students do to apply their conceptual understanding and skills to solve a problem, make a decision, perform a task, or make sense of new knowledge?
1. Begin the rebuild of the houses. Have the teams set a goal for the day and begin work on adding insulation to their models. It is highly recommended that the insulation is added to the outside of the houses to avoid it getting too close to the light bulb during the tests (which could cause a fire hazard).
2. If teams finish their rebuilds, you may begin retesting them. Have students complete the second chart in their notebooks in order to collect the data from the test (Data Log attachment).
1. Analyze your results of the pre- and post-insulation tests. Have students find the differences between the interior and exterior temperatures (averages). Students should write a summary and conclusion of their results in their notebooks. Some guiding questions: "What did you notice about the internal temperature after you added insulation?" "Did it go up or down?" "Why do you think this happened?" "What did you notice about the temperature collected from the roof of the house after adding insulation?" "Did the temperature go up or down?" "Why do you think this happened?" "Did you create an effective form of insulation for your house?"
2. Allow the students to compare their data with the other teams. You can do this by allowing them to move around the room freely or by making new groups. Try selecting one member from each team and have them form a discussion group. Disperse all of the students into the same type of groups. Before returning to their engineering teams, have students write a brief summary about the results shared with them in their discussion group. Have them answer the following questions: "How does your model's insulation compare to other students' houses that used the same material?" "How does it compare to other students' houses that used different materials?" "Which material do you think worked the best?" "Could there be a flaw in the results?"