Weight of Air Kit (LSE) How can you prove that air has weight? By weighing our can ?before? and ?after.? Simple concepts are not always intuitive, and the air we breathe is not an abstraction. Prove it with our low-cost lab that will make believers out of your middle school students. Includes: Pint-size seamless, aluminum can with attached plastic valve; instructions. You need: scale/balance, vacuum pump. Qty :