## Reflection: Modeling Electric Energy: Evaluating the Cost - Section 3: Watts In a Lightbulb Activity

Sometimes I learn an easier way to do things from my students. While asking students to present their Solution to the problem, there was a group that brought up more elegant solution than mine. I found it to be more simple and understandable and I congratulated them on finding such a path to the final answer.

In my solution to find the cost savings of using the LED over the incandescent, I first figured out how much both bulbs cost to operate for a year when used for 2 hours a day. Then I determined how many years the LED would last given its 20,000 hour life span and multiplied that by the cost savings per year to get a total of \$180.  The Students Elegant Solution was to simply apply the cost formula to both bulbs for 20,000 hours (the life of the LED) and see how much money was saved, which is also \$180. I let them and the whole class know that I preferred that student group's solution over mine and that in the future I will use theirs.

Modeling: Multiple Paths to the Same Answer

# Electric Energy: Evaluating the Cost

Unit 4: Electrostatics and Circuits
Lesson 15 of 16

## Big Idea: When evaluating the cost of an electronic device, the cost of operation, as well as the upfront cost are important to consider.

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50 minutes

### Jameson Parker

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