| One of the best science fair project ideas for students | | | | - Scissors |
| that are particular interested in the science and | | | | - Tape |
| mathematics of light travel is the Joly Photometer. This | | | | - Identical light fixtures |
| project allows students to use the inverse square law | | | | - Measuring tape (not a ruler) |
| to measure light intensity. This might not be one of the | | | | - Several kinds of light bulbs |
| best projects for students in lower grades, as the | | | | Procedure: |
| project does require an understanding of some difficult | | | | Follow these steps in order to successfully complete |
| mathematic concepts. | | | | one of the best science fair project ideas for |
| In order to perform this experiment, students will need | | | | determine how light works differently with different |
| to spend between $20 and $50. The project should | | | | bulbs: |
| take about a week, which makes it one of the more | | | | |
| time-consuming science fair project ideas that I've | | | | 1. Cut one slab of the wax in half. (Each box of wax |
| come across. Also, students might want to have a | | | | should have four slabs). |
| parent around to make sure the project is done safely. | | | | 2. Cut aluminum foil to be the same size as the slabs |
| Objective: | | | | and place it in between the 2 slabs. |
| During this project, you will measure the light intensity | | | | 3. Create a cardboard box around the slabs. Use tape |
| of light bulbs using your very own hand-crafted | | | | to hold it together. |
| photometer. | | | | 4. Make 3 windows in the sides of the cardboard box |
| Introduction: | | | | (one side will not have a window). This is your |
| Through this project, you will learn that different light | | | | photometer. |
| sources have different powers to project light into a | | | | 5. Place the photometer straight between 2 light |
| room. Every light bulb in your home might not have the | | | | fixtures at equal distances and equal heights. Make |
| same ability to emit light the same distance. During this | | | | sure these light fixtures are the only sources of light in |
| project, you will learn about the basic differences | | | | a room. |
| between how light bulbs work. Plus, you'll build and use | | | | 6. With the light bulbs illuminated, move the photometer |
| your very own photometer. | | | | between the two light bulbs until the wax has the |
| Terms and Concepts You'll Need to Know: | | | | same level of brightness on each side of the aluminum |
| You'll learn much more about these terms and | | | | foil. |
| concepts through the course of your experiment, but | | | | 7. To find the inverse square law, use the standard |
| it's a good idea to start with a basic knowledge of | | | | equation, which is found here. |
| them: | | | | 8. One of your light bulbs should be your standard bulb. |
| - Inverse square law (you'll learn lots about this law!) | | | | This bulb should be called I1. To find the intensity of the |
| - Incandescent light bulbs (you may already have | | | | second light, make sure you divide the first light by the |
| some in your home) | | | | square of the distance and make it equal to the |
| - Compact fluorescent light bulbs | | | | second light divided by the square of the distance so |
| - Photometer (you'll make your own) | | | | both lights are equidistant from the meter. |
| Questions You'll Answer: | | | | 9. Measure the distance from each light bulb to your |
| - What makes incandescent light bulbs work? | | | | photometer (measure to the foil). |
| - Why do incandescent light bulbs die? | | | | 10. Use the equation to calculate the intensity of each |
| - What makes fluorescent light bulbs work? | | | | bulb. |
| - Why do fluorescent light bulbs die? | | | | 11. In order to find out how efficient each bulb is, divide |
| - Which is the longest lasting light bulb? | | | | the relative intensity by the wattage of the bulb. |
| - Which light bulb makes light most efficiently? | | | | Again, this is one of my favorite science fair project |
| Materials You'll Need: | | | | ideas for students that enjoy math and physics. |
| You shouldn't have to pay more than $50 for all of | | | | However, it can be tough for those students that don't |
| these materials, but you'll probably find most of them in | | | | quite understand tricky equations. Science projects |
| your home already: | | | | should be fun - so have fun doing this project! |
| - One pound of paraffin wax | | | | If you're ready to get going with your own light intensity |
| - A sharp knife | | | | science project, your next step is to download a free |
| - Foil | | | | copy of "Easy Steps to Award-Winning Science Fair |
| - Cardboard box (small) | | | | Projects" from the link below right now. |