That heat flows from hot to cold is an unavoidable truth of life. People have put a lot of effort into stopping this natural physical behavior, however all they have been able to do is slow the process. Student teams investigate the properties of insulators in their attempts to keep cups of water from freezing, and once frozen, to keep them from melting.
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- Common Core State Standards for Mathematics: Math
- 1. Tell and write time to the nearest minute and measure time intervals in minutes. Solve word problems involving addition and subtraction of time intervals in minutes, e.g., by representing the problem on a number line diagram. (Grade 3)  ...show
- 3. Draw a scaled picture graph and a scaled bar graph to represent a data set with several categories. Solve one- and two-step "how many more" and "how many less" problems using information presented in scaled bar graphs. For example, draw a bar graph in which each square in the bar graph might represent 5 pets. (Grade 3)  ...show
- International Technology and Engineering Educators Association: Technology
- C. Things that are found in nature differ from things that are human-made in how they are produced and used. (Grades 3 - 5)  ...show
- J. Materials have many different properties. (Grades 3 - 5)  ...show
- D. Requirements for a design include such factors as the desired elements and features of a product or system or the limits that are placed on the design. (Grades 3 - 5)  ...show
- D. Identify and collect information about everyday problems that can be solved by technology, and generate ideas and requirements for solving a problem. (Grades 3 - 5)  ...show
- C. Compare, contrast, and classify collected information in order to identify patterns. (Grades 3 - 5)  ...show
- Massachusetts: Science
- 2.1 Identify a problem that reflects the need for shelter, storage, or convenience. (Grades 3 - 5)  ...show
- 3. Describe how water can be changed from one state to another by adding or taking away heat. (Grades 3 - 5)  ...show
- 7. Identify and classify objects and materials that conduct electricity and objects and materials that are insulators of electricity. (Grades 3 - 5)  ...show
- 5. Give examples of how energy can be transferred from one form to another. (Grades 3 - 5)  ...show
- 1.1 Identify materials used to accomplish a design task based on a specific property, i.e., weight, strength, hardness, and flexibility. (Grades 3 - 5)  ...show
- Next Generation Science Standards: Science
- Make observations to provide evidence that energy can be transferred from place to place by sound, light, heat, and electric currents. (Grade 4)  ...show
- Explain what "insulate" means and its implications in keeping things cold or warm.
- Conduct basic experimental processes.
- Describe how natural materials differ from human-made materials in terms of insulation.
- 4 3 oz. plastic cups
- 4 larger clear plastic cups
- 3 Styrofoam cups
- aluminum foil, 8½-in x 11-in piece
- 20 cotton balls
- teaspoon-sized spoon
- 4 rubber bands
- Data Chart, one per student, to be filled in during the experiment
- Results Chart, one per student, to be filled in after the experiment
- pitcher of warm water
- plastic wrap
- baking pan
- large book or magazine
|insulate:||To prevent or slow the transfer of electricity, heat or sound from one environment to another.|
|conductor:||A substance or body that can allow electricity, heat or sound to pass through it.|
|insulator:||A substance that resists the flow of heat, electricity or sound through it.|
|heat:||A form of energy that causes substances to rise in temperature or go through associated changes (melting, evaporation or expansion).|
|energy:||The capacity for doing work; can be in many forms such as electrical, mechanical, chemical, sound, light and heat.|
|conservation of energy:||A physics principle that states that energy can neither be created nor destroyed and that the total energy of a system by itself remains constant.|
|melt:||The process of changing from a solid to a liquid state through heat gain.|
|freeze:||The process of changing from a liquid to a solid (as ice) by loss of heat.|
Before the Activity
- Gather materials and make copies of the Data Chart and Results Chart, one each per student.
- To minimize the time spent in the classroom, prepare the insulating materials (although students CAN do this!!).
- Break up the foam cups into small pieces.
- Tear the aluminum foil into pieces and loosely crunch up the pieces.
- Pull the cotton balls apart a little and flatten them so that they resemble pancakes.
With the Students
- Present the Introduction/Motivation content. As a class, discuss what types of devices students have seen or used to keep things warm or cold. Talk about the materials from which they think these devices are made.
- Divide the class into groups of two to four students each.
- Have students examine the insulating materials they are going to be given and have groups make predictions about which they think will work best.
- Hand out the materials and blank charts to each group.
- Give each team its supply of three different insulating materials: Styrofoam, aluminum foil and cotton balls. Air is the fourth insulating material. Have students place enough of each insulating material in each large plastic cup so that it covers the bottom of the cup. Put nothing in the fourth large cup because air will serve as the insulator for that cup.
- Place a small 3 oz. cup in the center of each large cup.
- Have students fill the space between the cups with the same insulating material they used on the bottom.
- Place 3 teaspoons of warm tap water in each small cup.
- Have each group cover each of its large cups with plastic wrap held on by a rubber band.
- Place the cups in the freezer. Check the cups every 15 minutes to see which cup forms ice first. Record observations in the data chart. Keep checking until you see ice form in all four cups.
- Let the cups sit in the freezer until the ice is frozen solid in all cups.
- Remove the cups from the freezer and place them in a baking pan.
- Place a book or a magazine on top of the cups to keep them from tipping or floating.
- Pour very warm tap water into the pan.
- Have teams check their cups every few minutes to see which seems to be melting first, second, third and fourth. Record observations in the data chart.
- Conclude with a class discussion to share and compare results and findings. Ask the Investigating Questions. Use the attached rubric to gauge student accomplishments.
- What does "insulate" mean?
- What materials are used for insulation?
- Which insulator was best at slowing down the loss of heat from the warm water? Which was the worst?
- Did the results in the second half of the activity make sense with the results from the first half? Explain.
- Which is best for insulating a cup of ice: Styrofoam, foil or cotton?
- Would you rather have gloves made of fabric or aluminum foil? Explain your choice using what you know about the properties of heat transfer. (Example answer: Fabric gloves would keep my hands warmer than foil gloves because fabric insulates our bodies, slowing down the time it takes for our hands to become cold. On the other hand, metals speed up the transfer of heat so any warmth in my hands prior to putting on "aluminum gloves" would quickly escape through the foil, leaving me with very cold hands.)
- List at least three different products, devices or structures for which engineers applied their understanding of heat transfer principles in designing systems or choosing materials for the purpose of temperature regulation. (Tip: Think what might be designed by packaging, mechanical, electrical, computer and civil engineers, maybe items you use every day for comfort, life-saving necessity and entertainment.) (Example answers: thermos beverage containers, ice cream cart coolers, refrigerated trucks to ship foods at specific temperatures, coolers used to store and transport donated blood and body parts to patients, insulating materials in house walls and roofs to keep the inside cool or warm, special materials and weaves of fabrics used for clothing designed for specific weather conditions, wires made of metal and coated in plastic, fans and the liquids in radiators to keep electronics and motors from overheating. Specific example: If the casing that surrounds a tablet computer or pocket computer was made of rubber, the device would become hot very fast, and too uncomfortable to hold.)
- Have each student wrap a cup with aluminum foil and another cup with paper.
- Pour ice water into the cups.
- Have students hold the cups in their hands to judge which material is the best insulator.
Kessler, James H. and Andrea Bennett. The Best of WonderScience: Elementary Science Activities. Boston, MA: Delmar Publishers, 1997. pp 207, 210-211. ISBN: 0827380941
© 2013 by Regents of the University of Colorado; original © 2004 Worcester Polytechnic Institute
Center for Engineering Educational Outreach, Tufts University
Last modified: July 3, 2015