Day 138: Light Intensity vs. Distance

College-Prep Physics: Students designed a lab to determine the relationship between light intensity and distance. But first in the pre-lab, they made observations about moving the light, the square hole, and the grid paper. Then they had to invent a “light intensity factor” much like they had to invent the “cheesiness index” the other day. Finally, we agreed upon a common factor for us to all use in the lab: light intensity = # light bulbs / light area. This was similar to cheesiness = # bags of cheese / pizza area. The handout is here. The graph and analysis they had to do was identical to the math relationships we analyzed yesterday.

Conceptual Physics: Students used the bike generators and a diode to charge a rechargable NiCd battery. They pedaled for 20 minutes, stopping to take a battery voltage reading every 5 minutes.

HS Physics Teacher constantly questioning my teaching.

3 responses to “Day 138: Light Intensity vs. Distance”

1. Laura Hirsch says :

I am interested in the bike generator, battery activity. Do you have some directions, list of supplies, etc?

• Frank Noschese says :

Hi Laura,

It’s all part of the Physics The Works curriculum. All the materials are copyrighted. I was able to find a copy online at a used book seller. You need the student textbook (has the supplementary readings, which are important), the teacher guide (has notes, suggesstions, planning, materials list) AND the CD that goes with the teacher guide (has student activity handouts, which aren’t in the textbook or the print copy of the teacher’s guide).

The major supplies that you’ll need to round-up well in advance are the bikes and the generators. I was able to get some child bikes (great because they don’t take up much room) from our dump/recycling center. The generators I bought online. This was the model: http://www.realrecreationusa.com/p/Bike-Gear-Generator-Light-1819939.html It was important that the case of the generator was plastic because one of the activities had the kids examine a dissected bike generator. You will want to pick up a few extra, because I had one generator that didn’t work, and one with missing hardware.

It was a lot of fun, especially for me. Trying something new in class is always exciting.

Keep up posted!

• Frank Noschese says :

I forgot to add that there were a few activities I created myself for the unit. I posted those handouts to this blog on the days that I used them.