A class sand timer for understanding durations of time.
A tool for sharpening up pupils' estimations of time. Alternatively, simply use as a big sand timer for managing time in the classroom.
Help pupils gain a sense of short durations by timing, e.g., 10 seconds and asking them to close their eyes and put their hands up when they think the time is up.
Get pupils to count how many in a set time. E.g. How many times can you hop in 1 minute?