Get a sense for how long 100 seconds is with this handy checklist! Run in place for 100 seconds, do 100 hops on either foot, and more. Use the worksheet Time for Fitness Fun to help students in preschool, kindergarten, first grade, and second grade understand how long 100 seconds is. They can also count up to 100 using these active brain breaks. Early learners are free to use a timer and a helper to count with them as they go through each activity.