Fon of the assignment will be graded by your teacher Question: In a lab experiment, A square of black paper and a square of white paper are place directly under 100-watt lamps for 30 minutes. Predict what happens to the temperature of each paper during the experiment.

OVERVIEW

Students will use black and white construction paper and a light source to learn that dark objects

absorb more light and reflect less light than bright objects. The activity also demonstrates the conversion

of radiant light energy into heat energy.

CONCEPTS

• Dark surfaces absorb more visible light energy than bright surfaces

• Dark surfaces reflect less visible light energy than bright surfaces

• Energy can change forms, in this case from radiant light energy to heat

• Clouds, being bright, reflect significant amounts of sunlight and help to regulate Earth’s temperature

MATERIALS

• 2 thermometers

• Flood lamp, desk lamp, or area in direct sunlight

• Ruler

• Construction paper, 1 piece white, 1 piece black, or 2 sheets photocopy paper

• Scissors

• Cellophane tape or rubber bands

• 2 empty metal food cans, same size (be sure rims are not jagged)

PREPARATION

The paper and the cans can be prepared beforehand or prepared as part of the activity (see Procedure).

Although two cans with their tops completely removed can be used, the experiment will be more effective

(have fewer external effects), if only holes are placed in the cans’ lids, e.g., two holes from a bottle opener

to empty material out of the can, and one center hole created with an awl for the thermometer. Only one

hole is actually needed for the experiment - for the thermometer. Cans can optionally be filled with water,

or this can be done as a separate experiment to demonstrate the higher heat capacity of water compared to

air.

You can either use a flood lamp or a desk lamp (light bulb) to simulate sunlight, as described here, or

you can place the cans on a windowsill (window closed) or other sheltered area in direct sunlight. A flood

lamp will be the most effective option, causing the largest temperature increases.

PROCEDURE

Engagement

Discuss whether dark surfaces (e.g., asphalt) or bright surfaces (e.g., concrete) tend to get hotter in

sunlight. Which would you rather walk on during the day in the summertime? What color are solar cells,

for example those found on some calculators or freeway call boxes?

Explanation: I hope this helps! ∧    ∧

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