Example weights made from washers, with each washer's mass written on it in marker, showing the variation that can be expected for a given size of washer

Weights and Weighing

The need to weigh or add weight to something is a frequent feature in science activities. Fortunately, not only are there many different options – and what’s “best” varies by activity – but plenty of them are inexpensive or free! Here we discuss what we’ve found to be the most useful and kid-friendly choices.