Experiments With Reflecting Light

Focusing Light on an Object

• Put a flashlight or lamp in a dark room. Turn on and hold a mirror up to the light. Observe where the beam of light lands. Put a ball nearby and move the mirror, trying to get the beam of light to hit the ball. Then experiment with different objects in the room, trying to focus the beam of reflected light onto the objects.

Measuring Reflection Angles

• Make a narrow slit in the end of a shoebox. Put a flashlight in the box and put it on a table. Focus the beam of light on the center of a mirror (the mirror should be about 10 cm x 10 cm). Put a sheet of paper on the table in front of the mirror. Trace the path of the light to and from the mirror on the paper. Use a protractor to measure the angle of the light beam traced on the paper. Make a note of the distance between the light and the mirror and the angle of the light beam. Move the mirror further away from and closer to the beam of light. Retrace the light beams and measure the angles. Answer questions to further assess your findings, such as "How does the distance between the mirror and the light change the angle of the light beam?"

How Light Responds to Water

• Punch a hole in the bottom of a metal can. Put your finger over the hole and fill it with water. Turn off the lights. Using a flashlight, aim a beam of light down into the can of water. Move your finger and observe the stream of water as it drains out of the can.

  Place your finger in the stream of draining water. Tilt the can and observe the light as it responds. Plug up the hole with your finger again and refill the can with water. Hold the flashlight about 6 inches away from the water and to the side. Look at the ceiling. Explain how the light is passing through the water and reflecting off of the water at the same time.

Light Not Reflected Must Be Absorbed

• Wrap three jars with construction paper - one with white, one with black and one with any other color. Fill the jars with vegetable oil and put them in a sunny window sill. Record the temperature of the oil in each jar. Record the temperatures every 5 minutes for one hour.

  Look at how the colors affect the temperature and why. Answer why the experiment uses oil instead of water. If light is not reflected by a material, it must be absorbed. Explain how this relates to the result of your experiment.