## The Energy Efficient Chemical House

By Christopher Vargo, November 29, 2010

• Middle School

• Architecture

• Science

### Lesson Time

90 minutes for classroom activities and 20 minutes for homework

### Introduction

In this lesson, students will be challenged to design a house that can effectively heat and cool itself using only one heat source and one cooling source.

In Los Angeles, especially for 6th and 8th graders, methods of thermal energy (heat) transfer is an extremely important concept in the science curriculum.  Namely, the processes of conduction, convection, and radiation are of key importance.

This lesson will allow students to "review the challenge" by going over the needs and constraints of the house.  They can be given research opportunities, or the methods of heat transfer can be understood by the students beforehand.  Students will brainstorm solutions to the problem, and begin building their houses.

### National Standards

Science

Standard 9. Level III. Understands the sources and properties of energy

3. Knows that heat energy flows from warmer materials or regions to cooler ones through conduction, convection, and radiation

### Objectives

Students will be able to:

• design a house with efficient heating and cooling
• describe and utilize conduction, convection, and radiation in the design process
• understand that metals are good conducters of heat, while Styrofoam is a good insulator
• understand that heat rises and cool molecules sink in convection

### Resources

http://www.vtaide.com/png/heat2.htm -- a great interactive Web site explaining the three methods of heat transfer

### Materials

• handout detailing directions
• cardboard boxes
• Styrofoam
• a small battery powered heater
• ice
• a small container for each group
• tin foil
• safety scissors for each group
• thermometers
• a lamp or flashlight for each group (optional)

### Vocabulary

• conduction: the transfer of heat between two parts of a stationary system, caused by a temperature difference between the parts; transmission through a conductor
• convection: the circulatory motion that occurs in a fluid at a nonuniform temperature owing to the variation of its density and the action of gravity; essentially hotter (more widely spaced particles) rise because of lowered density, while cold particles then sink
• insulation: the action of separating a conductor from conducting bodies by means of nonconductors so as to prevent transfer of electricity, heat, or sound
• radiation: the process in which energy is emitted as particles or waves

### Procedures

Step 1:

1. Present the students with a handout that states the challenge: to build a house with only one heating unit and one cooling unit.  Begin the Design Process by allowing students to review the handout.

2. Explain to students that they will be building a house that needs to be heated in the winter and cooled in the summer.  The house will have a first floor and a second floor. A basement and an attic are optional.  The house should have at least two rooms on each floor (four rooms total).  Each student gets an extra lamp to heat one room, and there must be a staircase to join the two floors.  There can only be one cooling unit (represented by ice) and one heating unit (represented by a small battery powered heater).

3.  If you have computer resources, allow students to visit http://www.vtaide.com/png/heat2.htm.  Ask students to answer how will each method of heat transfer play into their house?

4. Students may be provided with a graphic organizer on their worksheet that allows them to effectively “Frame” the problem.  Ask the students, “Where in the house should each of the two (or three with the lamp) heating sources be placed?  What method of heat transfer lead you to this idea and what is the predicted outcome?”

5. Give students the opportunity to design their houses through collaboration, sketching, writing, and diagramming.

6. On their drawings, have the students label where the heating unit should go, and where the cooling unit should go and explain why.  Teacher should circulate to monitor student designs and make suggestions. Ask guiding questions to groups struggling for ideas such as:

• How can placing a heating or cooling unit somewhere heat or cool the entire home?
• What kind of materials could the walls be made of to help insulate or conduct heat?

7. Allow students to start building their model houses out of the cardboard material, tinfoil, Styrofoam, and heaters.  During this time, students may test their ideas through experimentation and testing of the ideas developed from the brainstorming session.

8. As peers, students can evaluate each other’s houses.  Students may explain why they made certain decisions, and how the house meets the two needs of the customer, which are maximum heating efficiency and maximum cooling efficiency.

9. Each group should be allowed between one and two minutes to present.

10. After feedback students can make corrections to their houses.

11. To articulate the solution and process, students may complete the last section of their worksheet which requires them to explain how their solution met the needs of the challenge and the reasoning behind their decisions.

### Assessment

1. Students can be asked a number of multiple choice or free response questions.

• Should the heater have been placed on the first or second story?  Why is that?
• What causes one object to be a good conductor?
• How does the flashlight heat the one room that is was placed in?

2. To allow instructional differentiation, some students can be allowed edited design challenges.  Advanced students can be provided with multiple floors and multiple heating/cooling units.  Students that need extra assistance will receive it through the use of graphic organizers, guiding questions, and teacher assistance.

### Enrichment Extension Activities

In their own homes (as well as those of friends, relatives, or even in the school), students can identify where the heaters and air conditioners are.  They can discuss if they are placed in the correct spots for maximum efficiency, and should be able to back up their answers with scientific reasoning.

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