Squeeze a penny through the mouth of one of our clear balloons. Make sure that the penny goes all the way into the balloon so that there is no danger of it being sucked out while blowing up the ...

I'm reading Randall Munroe's book How To: Absurd Scientific Advice for Common Real-World Problems. I probably don't have to tell you this, but it's awesome (as is everything from Randall Munroe, the ...