Structural and Thermal Engineering
“Penguins”
An OSU Improving Teacher Quality:
Sustainability Engineering Lesson
Revised By Owasso 8th Grade Center
Problem-Based Learning Scenario
Your team’s challenge is to design the most efficient house to extend the lives of penguins. These houses would be built at the north and south poles to help penguins survive the warmer temperatures caused by global warming. Ultimately, you will have to argue for the efficiency of your Penguin Palace using data acquired through your design and experimentation.
Here are your tasks:
1) You will be given a kit of material samples and a price list.
2) You will be given $250 to purchase the materials your group decides would be most efficient to build your Penguin Palace.
3) You will build a palace that has the best insulating properties.
4) You will place your palace with your four-penguin family in the Global Warming Simulation Unit.
5) You will measure the mass of water collected over time, the mass that is not melted, and temperature; record and graph your results on your data sheet; and determine rate of melting.
Roles Guidelines:
Each member of a team brings critical expertise to this process. Each of you must serve as your team’s expert, gathering and sharing information to make your best case for your penguin palace. Descriptions below are basic guidelines, but you may think of additional things you can contribute to your team.
Mathematician—It is important that your Penguin Palace is affordable. You will be given a cost sheet for all materials, and be in charge of calculating the costs of the palace. You will use your expertise to interpret and explain data calculations and graphs.
Scientist—As a scientist, you will need to ensure accuracy and appropriateness of data collection, recording, and reporting. You will use your expertise to explain to the team conduction, convection and radiation. You will help your team select appropriate materials to build your penguin palace.
Language/Communication Specialist—Communication of your team’s work is going to be very important. Your task is to take the information acquired through the data collection process and create a new page on your wiki for Mr. Gore to view. The page must contain: a 100-word persuasive paragraph regarding your design process, a picture or diagram of the design, the math and science data collected, and a cartoon illustrating your understanding of global warming.
Media/Technology Specialist—Your job will be to create a cartoon illustrating your understanding of global warming. Use the free tools at http://toondoo.com. The cartoon will be posted to the wiki page under direction of the Language/Communication Specialist.
Social Scientist—You will need to contextualize the environment of the Penguin Palace. Using sources such as Google Earth, create a scenario that will explain the conditions the penguins will be facing. Determine the weather conditions--wind, temperature, precipitation etc.
Content Background Information Required:
Students should have basic understanding of the dependence of organisms and the environment within an ecosystem; conducting investigations; and the basic nature of matter. See Appendix A for specific science background content.
Student Objectives:
· As a team students will determine which materials are best to insulate the penguin family of four from global warming.
· As a team, students will use available materials to design a structure that will keep their "penguin family" from melting.
· Students will use budgeting skills to purchase the necessary materials to build their structure.
· Students will test their structure to measure the effectiveness of the insulation design.
· Students will create a cartoon using http://toondoo.com that will help their group communicate issues learned about penguins.
· Students will collect and communicate data in a group presentation.
Materials:
This is a listing of all the materials to be used during the activity outlined in the lesson plan. All quantities are given by the number of items required per group. The teachers should determine in advance the number of groups the class will be divided into, and purchase the required quantities as well as any spare material that may be needed.
Appendix A
Science Background: There are three main types of heat transfer, convection, conduction, radiation.
Convection is the transfer of heat by the actual movement of the warmed matter. Heat leaves the coffee cup as the currents of steam and air rise. Convection is the transfer of heat energy in a gas or liquid by movement of currents. (It can also happen is some solids, like sand.) The heat moves with the fluid. Consider this: convection is responsible for making macaroni rise and fall in a pot of heated water. The warmer portions of the water are less dense and therefore, they rise. Meanwhile, the cooler portions of the water fall because they are denser.
Conduction is the transfer of energy through matter from particle to particle. It is the transfer and distribution of heat energy from atom to atom within a substance. For example, a spoon in a cup of hot soup becomes warmer because the heat from the soup is conducted along the spoon. Conduction is most effective in solids-but it can happen in fluids. Have you ever noticed that metals tend to feel cold? Believe it or not, they are not colder! They only feel colder because they conduct heat away from your hand. You perceive the heat that is leaving your hand as cold.
Conduction is mainly seen with solid objects, but it can happen when any materials come into contact. When you put your hand in a container of warm water, you hand it heated by conduction from the water. Some materials are better conductors of heat than others. For example, metals are good conductors of heat, while a material like wood isn't. Metal heated on one end will soon be hot on the other end too, while that is not true with a piece of wood. Good conductors of electricity are often good conductors of heat. Since the atoms are closer together, solids conduct heat better than liquids or gasses. This means that two solid materials in contact would transfer heat from one to the other better than a solid in contact with a gas or a gas with a liquid.
Radiation: Electromagnetic waves that directly transport ENERGY through space. Sunlight is a form of radiation that is radiated through space to our planet without the aid of fluids or solids. The energy travels through nothingness! Just think of it! The sun transfers heat through 93 million miles of space. Because there are no solids (like a huge spoon) touching the sun and our planet, conduction is not responsible for bringing heat to Earth. Since there are no fluids (like air and water) in space, convection is not responsible for transferring the heat. Thus, radiation brings heat to our planet.
Thermal Insultation
Thermal insulation is the method of preventing heat from escaping a container or from entering the container. In other words, thermal insulation can keep an enclosed area such as a building warm, or it can keep the inside of a container cold. Heat is transferred by from one material to another by conduction, convection and/or radiation. Insulators are used to minimize that transfer of heat energy. In home insulation, the R-value is an indication of how well a material insulates.
Where thermal insulation is used
If you have an object or area that is at a certain temperature, you may want to prevent that material from becoming the same temperature as neighboring materials. This is usually done by employing a thermal insulation barrier.
For example:
* If the air outside is cold, you may want to protect your skin by wearing clothes that keep the cold out and the body warmth in.
* If your house has cool air inside during the summer, you may want to prevent the temperature from becoming the same as the hot air outside by having the house well insulated.
* If you have a hot drink, you may want to prevent it from becoming room temperature by putting it in a thermos bottle.
In any location where there are materials of two drastically different temperatures, you may want to provide an insulating barrier to prevent one from becoming the same temperature as the other. In such situations, the effort is to minimize the transfer of heat from one area to another.
How insulation works
Insulation is a barrier that minimizes the transfer of heat energy from one material to another by reducing the conduction, convection and/or radiation effects.
Insulating materials
Most insulation is used to prevent the conduction of heat. In some cases radiation is a factor. A good insulator is obviously a poor conductor.
Less dense materials are better insulators. The denser the material, the closer its atoms are together. That means the transfer of energy of one atom to the next is more effective. Thus, gases insulate better than liquids, which in turn insulate better than solids.
An interesting fact is that poor conductors of electricity are also poor heat conductors. Wood is a much better insulator than copper. The reason is that metals that conduct electricity allow free electrons to roam through the material. This enhances the transfer of energy from one area to another in the metal. Without this ability, the material--like wood--does not conduct heat well.
Insulation from conduction
Conduction occurs when materials--especially solids--are in direct contact with each other. High kinetic energy atoms and molecules bump into their neighbors, increasing the neighbor's energy. This increase in energy can flow through materials and from one material to another.
Solid to solid
To slow down the transfer of heat by conduction from one solid to another, materials that are poor conductors are placed in between the solids. Examples include:
* Fiberglass is not a good conductor nor is air. That is why bundles of loosely packed fiberglass strands are often used as insulation between the outer and inner walls of a house.
* Heat cannot travel though a vacuum. That is why a thermos bottle has an evacuated lining. Heat cannot be transferred from one layer to the other through the thermos bottle vacuum.
Gas to solid
To slow down the heat transfer between air and a solid, a poor conductor of heat is placed in between.
A good example of this is placing a layer of clothing between you and the cold outside air in the winter. If the cold air was in contact with your skin, it would lower the skin's temperature. The clothing slows down that heat loss. Also, the clothing prevents body heat from leaving and being lost to the cold air.
Liquid to solid
Likewise, when you swim in water, cold water can lower your body temperature through conduction. That is why some swimmers wear rubber wet suits to insulate them from the cold water.
Insulation from convection
convection is transfer of heat when a fluid is in motion. Since air and water do not readily conduct heat, they often transfer heat (or cold) through their motion. A fan-driven furnace is an example of this.
Insulation from heat transfer by convection is usually done by either preventing the motion of the fluid or protecting from the convection. Wearing protective clothing on a cold, windy day will inhibit the loss of heat due to convection.
Insulation from radiation
Hot and even warm objects radiate infra-red electromagnetic waves, which can heat up objects at a distance, as well as lose energy themselves. Insulation against heat transfer by radiation is usually done by using reflective materials.
A thermos bottle not only has an evacuated lining to prevent heat transfer by conduction, but it also is made of shiny material to prevent radiation heat transfer. Radiation from warm food inside the thermos bottle is reflected back to itself. Radiation from warm outside material is reflected to prevent heating cold liquids inside the bottle.
R-value
The R-value of a material is its resistance to heat flow and is an indication of its ability to insulate. It is used as a standard way of telling how good a material will insulate.The higher the R-value, the better the insulation.
Definition
The R-value is the reciprocal of the amount of heat energy per area of material per degree difference between the outside and inside. Its units of measurement for R-value are:
(square feet x hour x degree F)/BTU in the English system and
(square meters x degrees C)/watts in the metric system
Appendix B
Save the Penguins Project Cost Sheet
Material / Price $ / Quantity / Cost $Bake Fresh paper baking cups / 30
Bake Fresh foil baking cups / 30
100% cotton balls, 10 per bundle / 2
Forster mini craft sticks, 10 per bundle / 20
Art Street construction paper pad, 9"x12" / 4
Creative Hands foam sheets, 9” x 12” / 40
White felt fabric, polyester, 3"x 3” wide / 40
Pink felt fabric, polyester, 3"x 3” wide / 40
Blue felt fabric, polyester, 3"x 3” wide / 40
Green felt fabric, polyester, 3"x 3” wide / 40
Duck bubble wrap, 3" x 12” / 10
Great Value heavy duty aluminum foil, 37.5 sq. feet / 4
PB Medical Supplies mylar foil 3” x 3” / 5
Appendix C
Save the Penguins Ledger ($250.00 Maximum)
Product/Material / Price x Quantity / Cost / Balance
Appendix D: Pre- and Post Test
Heat Transfer Evaluation
· This questionnaire is about your understandings of heat transfer.
· For each question, circle the answer that is closest to your understanding.