Name ____________________________________________ Date _____________________
“Flashlight Lab” Period ____________________
Light Intensity (Amount of Light Energy Per Unit of Area) vs. Angle of Insolation
a. k. a. The “Flashlight” Lab
Problem: How does the angle of insolation affect the intensity of light hitting a surface?
(Intensity amount of light energy measured in joules…per unit of area measured in squares)
Background Research (and preliminary observations): Provide a summary of the information you have found that relates to the
lab you are conducting. You must have at least once source and cite your source(s).
Think about how the intensity is affected by the angle of insolation, the latitude of the location, the time of day, the
time of year, etc.
Hypothesis: If the angle of insolation _________________________, then the light concentration (amount of light per unit area) will
_______________________________ because ________________________________.
Materials: flashlight, ruler, protractor, graph paper, pencil
Make a list of steps you will follow to conduct your experiment. (You may also want to add diagrams/labeled illustrations to your list
Data/Observations: All results of the experiment including observations and data collected. Typically this section will include a
data table (and/or one or more diagrams). Do not forget titles, labels, and units. ***Attach your graph paper as part of this section.
Data Analysis: Graphs, charts, and a short summary describing (patterns or trends in) the data collected. Do not forget titles,
labels, and units. For graphs, put your independent variable along the x-axis/bottom of the graph and your dependent variable along
the y-axis/side of the graph. Give your graph a title “dependent variable” Versus “independent variable”.
***For each trial, make sure to:
1. Determine the area (of paper in squares) lit up by the flashlight.
2. Calculate the light intensity (amount of light energy per unit area) by:
a. Assuming that the flashlight is giving off 50,000 joules of energy and dividing that by the area (of
paper in squares) lit up by the flashlight.
b. SHOW YOUR WORK!
3. Graph your results using a bar graph.
4. ***Attach your graphs & your graph paper with your data that you collected to you lab write-up!!!
Conclusions: ANSWER IN COMPLETE SENTENCES!
1) Accept or reject your hypothesis, and explain why you accepted or rejected your hypothesis using data from the lab.
2) Include a summary of the data (ex. averages, highest, lowest, control, independent/dependent variables, etc.) to help the
reader understand your results.
3) Discuss possible errors that could have occurred in the collection of the data (experimental errors), and discuss ways you
could improve your experiment if you could perform it again.
4) Discuss how this investigation is related to real-life. (How do the results relate to real-life problems? What future
explorations and investigations might come from this experiment?)
Post-Lab Discussion/Questions: (Use complete sentences, proper spelling, and proper grammar. Remember… pretend your
reader does not have the question in front of him/her and that he/she knows nothing about the topic/experiment.)
1. What is meant by the term insolation? (What is it an abbreviation of?)
2. Based on your calculations of light intensity (from your data analysis section), make a conclusion regarding the angle of
insolation and the intensity of insolation.
3. At what time of day does Darien receive the greatest intensity of insolation? Explain your reasoning.
4. At what time of year does Darien receive the greatest intensity of insolation? Explain your reasoning.
5. If you were to put a solar panel on your house, at what angle, 30°, 45°, or 90°, would you want the sun’s rays to hit the panel?
Works Cited: List all sources of information (books, internet, interviews, journals, magazines, textbook, etc.) in MLA format.
IMPORTANT!!! This lab must be typed or written up using the above format. Make sure to use all section headings (underline and
bold them…). All parts should be written in complete sentences. Do not use vague words like “it,” “they,” or “them,” etc. unless you
first state what you are referring to!