Arm span

Arm span is the distance from the tip of one hand to the tip of the other hand when you stretch your arms out really wide like a bird. It's kind of like your wingspan! Your arm span is different from your height because you might be taller or shorter than someone else, but if you both stretch your arms out, your arm spans might be the same. Scientists like to measure arm span because it can help them figure out things like how big your clothes should be or how far you can reach.