Cost of light bulbs

With incandescent and halogen bulbs banned since 2023, students compare CFL, LED, and Smart LED bulbs, calculate energy use in kilowatt-hours, and determine which bulb is the better deal over time. 

In this updated activity, students work with decimals, unit rates, and proportional reasoning to complete a table, then graph (linear & piecewise function with your guidance) each bulb's total cost to compare the options and decide for themselves whether they'd switch bulbs at home and why. This is a great activity for Earth Day or really any other day of the year. 

📝 Suitable for Grades 6–8 
⏰ Min. 45 mins