This is probably the first time im talking about physics since high school so this might sound a little stupid. Bear with me If i had 1 cubic feet of helium and i wanted to compress that helium to the same density as air by pressing the container A) what kind of force would i need to do that and B) what kind of container would be strong enough to withstand that kind of pressure.
See if this is what you are looking for: I'm assuming you want compress helium to achieve the same weight per unit volume as air. Helium has 2 protons, and two neutrons - weight of 4. Air is 80% nitrogen, which is a molecule (N2), with 7 protons, and 7 neutrons each, for a weight of 14, each, X2, 28. Air is 20% oxygen, which is a molecule (O2), with 8 protons, and 8 neutrons each, for a weight of 16, each, X2, 32. Total weight 28.8. Helium will have weight when compressed to 7.2 atmospheres, and cooled to room temp. Why cooled? Because compressing the helium to the right volume will incease the temperature to ~480F, which will require more than 7.2 atmospheres.
If that 7.2 atmospheres was a weight placed on top of the container with the helium, how heavy would it be? The atmospheres/newtons/pascals etc dont say anything to me
Place a bladder with 1cu ft of helium into a hole, 1 foot deep, and 1 foot square. Insert a 1 foot square weight on top of the bladder, of 15,241lbs. 7.2 * 14.7PSI = 105.84 * 144 sq in = 15,241. As the temperature drops to room temp, the weight will squish the bladder to 1.667" tall.
