Samm Vetrone

Kristin Mohr

Standard:P.PM.03.51 Demonstrate how some materials are heated more

than others by light that shines on them.

Grade Level: 3rd Grade

Lesson Title:

Heat Absorption and Color

Lesson Objectives:

After completion of this lesson, the students will be able to:

  1. Describe the relationship between color and light absorption and reflection.
  2. Explain the difference between conduction and radiation.
  3. Collect data from the experiment they have created.
  4. Graph data gathered from experimentation.
  5. Work together as a group to perform a successful experiment.

List of Materials:

For each group:

1.2 metal soup cans with tops removed, one painted black the other with no paint.

2.Heat lamp

3.2 cups of water (at room temperature)

4.2 liquid thermometers

5.Clock or stop watch

6. Data chart provided

7. Paper for data graph

8.Markers and writing utensils

Previous Knowledge:Students should know that the light we see is made up of all of the colors of the Visible Spectrum. Students can identify that light is a form of energy.

Engage:

The students will be engaged by a discussion. They will be asked if they have ever stepped on a blacktop driveway on a hot day. Is it hotter than a regular concrete (whitish-gray) sidewalk? How can it be that two pieces of matter, in this case the ground, are in the same environment and receive the same amount of sunlight, yet one is much hotter than the other? What difference in their appearance could have an effect on their temperature?

Explore:

Each group of students will heat two cans of water, one black the other silver, with a heating lamp and record the temperature of the water at a chosen time interval , for example every 2 minutes). Before the experiment is conducted, the students will each decide as a class what variables they want to keep constant in their experiment. For example, how long they will keep it under the lamp, the time intervals that the temperature will be recorded, or the distance from the cup to the lamp. During each interval of their choice, each student will record the temperature read for both the black and silver can on the attached data table. Finally, the students will plot the data their group has recorded and create a line graph that representative of their groups’ data.

Explain:

Students will as, a group, explain the results of their experiment and describe their data graph. The teacher will lead the discussion by asking the students if they were able to make any conclusions about their findings.

The class will be taught the information in the form of guided discovery. The teacher will facilitate a discussion and ask questions to help students derive their own conclusions about the experiment. The class will discuss why the black can’s temperature increased at a faster rate.

  • What is light? Energy
  • If something is hotter or has a higher temperature does it have more energy or less energy? More
  • What does that say about the color black if it was heated at a faster rate? It must absorb more energy than lighter colors.
  • If the lighter colors have less energy, where does the light energy go if is not absorbed by the object? It is reflected.

The class will discuss how radiation is a process of energy transfer, or heating. The waves that make up light contain energy. When they are radiated, an object either absorbs the energy or reflects the energy. When we see colors we are seeing the waves of the Visible Spectrum that are reflected. If all of the waves are reflected we see white. If all of the waves of energy are absorbed by the object we see black. The fact that all of the energy from the light is absorbed by the black can made its temperature rise at a faster rate (more energy means a higher temperature).

  • If the can absorbed the energy, how did the water’s temperature increase?

Finally, the class will discuss how conduction transferred the energy. Conduction is the transfer of energy from molecule to molecule through direct contact. An example would be when a metal spoon gets hot from touching a hot pot. In conduction, the energy moves from warmer things to colder things.

  • What does this say about the can and the water in the experiment?
  • What was colder and what was warmer?

Conclude that the energy was transferred by conduction from the warmer can to the colder water, consequently heating it.

Elaborate:

Students will be given the following scenario and will answer it in the form of a journal entry:

You and your friend are planning to spend the day at an amusement park. It is about 90 degrees Fahrenheit outside and the sky is very clear. When you pick up your friend, he is wearing a black t-shirt and black shorts. Would you suggest that he changes before you leave? Explain why or why not. Use your experiment results and the information you have learned to support your decision.

Evaluate:

The students will be evaluated on:

--Their graph and data table with accurate information. Are all the temperatures accurate throughout the group? Does the graph correctly reflect the information on the data table?

--Working together as a group through observation of walking around the room. Did each student participate in the experiment? Did they work together to create and carry out the experiment?

--Their journal entry answering the “Elaborate” question. Did they answer correctly? Did they use concepts from the lecture and experiment to support their answer?

References:

Woolridge, Mike. (November 18, 1994) Cool Ideas for Roofs. Science Magazine. p 43.

Heat Absorption and Color

Data Table

Name: ______

Group Members: ______

Time Interval:_____ / Black Can / Silver Can
Time:______/ Temperature:____˚C / Temperature:____˚C
Time:______/ Temperature:____˚C / Temperature:____˚C
Time:______/ Temperature:____˚C / Temperature:____˚C
Time:______/ Temperature:____˚C / Temperature:____˚C
Time:______/ Temperature:____˚C / Temperature:____˚C
Time:______/ Temperature:____˚C / Temperature:____˚C
Time:______/ Temperature:____˚C / Temperature:____˚C
Time:______/ Temperature:____˚C / Temperature:____˚C
Time:______/ Temperature:____˚C / Temperature:____˚C
Time:______/ Temperature:____˚C / Temperature:____˚C

Temperature Change Versus Time

Create a line graph of your results. Plot the temperature change for both cans. Use a different color to draw each line (one for the black can and one for the silver can).