Tinkerclass (Week 2 Day 4): Improve & Retest

It's day 4 of TINKERCLASS--the improve and retest phase. See if you can improve your invention from yesterday, test it again, and then share your results with us! This week's project features the Wow in the World episode, Rat Race! See Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.