Let the Sunshine In

Category:Experiment

Learning Objectives:

1. Students will predict the relative amount of the sunŐs heat which will flow through different window coverings.
2. Students will measure the amount of sunlight (heat) which flows though various window coverings by conducting a controlled simulation experiment.
3. Students will record their findings in the form of a chart.
4. Students will use their results to draw conclusions about the relative quality of each window covering based upon its ability to control heat flow.

Materials, equipment and/or facilities:

• Access to sunlight (outdoors preferable)
• Water
• White paper, Scissors, and Tape to cover beaker sides
• Small pieces (the size of beaker tops) of various window coverings such as:
  • screens
  • tinted shading (lens from sunglasses will work)
  • curtain materials (may use more than one type)
  • window blinds
  • vinyl window shade
  • glass (to represent double panes)
• Beaker for each type of covering
• Thermometer for each type of covering
• Writing utensil and paper for chart

Sequence and duration of each part of lesson:
Introduction: 5 to 10 Minutes
Ask students to list different window coverings which they have observed in their home, school, car, or other enclosed structures. Write their ideas on the board and then ask which covering they believe best limits the flow of heat. Which do they think keeps the inside of a home warmest/coolest in the summer/winter? Inform them that the following experiment will help them to answer these questions.

Set-up: 10 to 15 Minutes
Assign students to:

1. Fill each beaker to the same level (at least 3 cm.) with water.
2. Place a thermometer in each beaker.
3. Cover the sides with white paper.
4. Number them.
5. Cover the top of each beaker with one of the different window coverings.

Each student should construct a chart to record the beaker number, temperature of water for each beaker, and the type of window covering. Set the beakers in a sunny location.

Wait time: Approximately 30 Minutes
Time must be allowed for the water to absorb the heat energy from the sun that passes through the covering. During this period, a teacher may develop an original activity for students or may choose from the following:

1. Instruct students to construct a hypothesis for each beaker's relative heat absorption. Have them list the beakers in order from what they believe will be the coolest to the one they think will be warmest. They may even be asked to go a step further and predict how many degrees they believe the water temperature in each beaker will increase.

2. Travel around the school, observing and recording different window coverings, the position of windows relative to the sun's rays, and the relative temperature of the rooms near these windows.

Results and Conclusions: 10 to 15 Minutes
Return to the beakers. To insure uniformity, the teacher should read to the students the new temperature of the water in each beaker and have each student carefully record these results on their chart. Ask students to write their conclusions about which materials best control the flow of heat. Have them answer the following questions:

Which covering would keep an enclosed structure warmest/coolest in the summer/winter?
Which of your hypotheses were correct?

Evaluation: A teacher may determine whether or not the student objectives have been met through asking the questions in the conclusion sections.

Variations: Students may investigate the absorption of different colors or materials to determine which clothes might be best to wear in the summer or winter. They may also test the quality of various sunglass lenses or brands of sunscreen.