Toilet paper races
Students in my Algebra classes chose their own problem to use to investigate ratios and proportional relationships. My first period chose to test toilet paper races. In each race, one student would hold an end of the toilet paper roll and the other student would hold the roll and run backwards as far as he or she could in a certain amount of time. They began by doing some trial runs in which they tested and recorded how far they could go in three seconds. Then they worked at predicting how far they could go in 17 seconds. Students determined unit rates for each runner, graphed their predicted distances for any given time, and wrote an equation for their distances with respect to time. Students then tested their hypotheses by repeating the race and measuring their distance after 17 seconds.