Tomas was ten, and he said, "Air has weight." His older sister Elisa laughed. "Air is nothing!" she said. So Tomas put a flat football on the kitchen scale and wrote down the number. Then he pumped the ball until it was hard and weighed it again. It was a few grams heavier!
Elisa checked the scale twice. Their father explained that the air around us presses on everything. Tomas showed the class, and he won a ribbon at the science fair. Elisa became his assistant. She called herself "Head of the Air Department."