Properties of Light
July 28st, 2014
Lab #10
Properties of Light
Purpose:
The ideal purpose of this lab activity is to investigate the relationship between the frequency of the light (color) and the energy produced by different colors of light. Other purposes of this experiment include calculating the proper current for each LED, measuring the evaporation rate of rubbing alcohol, and being able to discuss the outcome of the relationship in light energy and the color of the light producing the energy.
Materials:
Light Emitting Diodes (red, green, blue)
LEDs and circuits (from previous lab)
Pipette (or eyedropper)
Rubbing alcohol
Index card
9-volt battery
Flashlight
Stopwatch
Small cardboard box (shoe box)
Procedure:
1. Create a location for applying light from the LED to the drop of alcohol while minimizing the effect of air currents on the evaporation rate, by making a three-sided enclosure with the cardboard box.
2. Place a single drop of isopropyl (rubbing) alcohol on an index card within the enclosure using the eyedropper. Try and make sure you are using the same size drops when repeating.
3. Without the LED present, measure the time it takes for the drop to evaporate. You will notice that the spot on the card from the alcohol will not be visible, and record this evaporation time in an Excel spreadsheet. It may be helpful to used a flashlight to help watch for when the spot is no longer visible.
4. While holing different colored LEDS over the alcohol, repeat the same procedure. The current through the LED should be the same, as well as the distance from the LED to the drop should also remain the same for each time.
5. Repeat the procedure for each color of LED at least 10 times and calculate an average time of evaporation for each color.
6. Make a graph of evaporation time versus frequency of the LED. (Look up the frequency of the diode).
7. Based on results, discuss and make calculations.
Data/Calculations:
Lab #10
Properties of Light
Purpose:
The ideal purpose of this lab activity is to investigate the relationship between the frequency of the light (color) and the energy produced by different colors of light. Other purposes of this experiment include calculating the proper current for each LED, measuring the evaporation rate of rubbing alcohol, and being able to discuss the outcome of the relationship in light energy and the color of the light producing the energy.
Materials:
Light Emitting Diodes (red, green, blue)
LEDs and circuits (from previous lab)
Pipette (or eyedropper)
Rubbing alcohol
Index card
9-volt battery
Flashlight
Stopwatch
Small cardboard box (shoe box)
Procedure:
1. Create a location for applying light from the LED to the drop of alcohol while minimizing the effect of air currents on the evaporation rate, by making a three-sided enclosure with the cardboard box.
2. Place a single drop of isopropyl (rubbing) alcohol on an index card within the enclosure using the eyedropper. Try and make sure you are using the same size drops when repeating.
3. Without the LED present, measure the time it takes for the drop to evaporate. You will notice that the spot on the card from the alcohol will not be visible, and record this evaporation time in an Excel spreadsheet. It may be helpful to used a flashlight to help watch for when the spot is no longer visible.
4. While holing different colored LEDS over the alcohol, repeat the same procedure. The current through the LED should be the same, as well as the distance from the LED to the drop should also remain the same for each time.
5. Repeat the procedure for each color of LED at least 10 times and calculate an average time of evaporation for each color.
6. Make a graph of evaporation time versus frequency of the LED. (Look up the frequency of the diode).
7. Based on results, discuss and make calculations.
Data/Calculations: