ELI5. If I exhale before going on a scale, then inhale deeply afterwards, will the reading on the scale increase, decrease, or not change?

Question

Of course the difference is quite miniscule but I became curious while standing on my scale exhaling to look leaner than I was. Unfortunately my scale isn’t precise enough to be able to test this so here I am. Any explanation would be greatly appreciated 🙂

In: Physics

Answer 1

Exhale into a large empty graduated cylinder that has a piston in the interior (like blowing into an empty syringe to fill it with air.) They make things like this for measuring lung capacity. Measure.your lung capacity. Then multiply your lung capacity by the mass of air at your altitude and temperature. That will tell you exactly how much mass you gain by inhaling.