Plastics Moulding

Storing gas in plastic? boxes with plants in them for a science fair project?

I want to see if plants in a high gas concentrated area will have a different growth than plants in the open air for a science fair project. Also, how would I get c02 into a box, and make it stay there for a couple of days. I'm trying not to make anything complicated, and the box to hold the plant will probably be 6 plastic squares hot glued together with air vents and a hole to put c02 or some other gas in.

Public Comments

Sounds like a very interesting experiement. It depends on how long you want to have it concentrated. Plastics are permeable to gases (that is why potato chip bags are coating with a thin layer of metal, to keep H2O vapor out and the chips crispy). If you make the box out of glass (or use a large mouth glass jar), no gases will leak in or out. Remember that, if you are pumping gas into a sealed bottle, you need to be careful that you don't pressurize the glass bottle. If you put more than atmospheric pressure inside the glass and there is no way for the "extra" gas to escape, it will "pop" or explode. If you use a flat piece of plastic (which could have holes to let gas in/out) and just used a little weight to hold it on top of the glass jar, that will work well and there will be no risk of presurizing the jar. You can buy small CO2 gas cylinders at most grocery stores, they are used to carbonate drinks. They are also used to power paint ball guns so be prepared for the amount of pressure inside the cyclinder. There are also small gas cyclinders filled with a nitrogen based gas for whipped cream dispensers. Another source of CO2 is dry ice. If you put a piece of dry ice in a sealed vessel, it will generate significant CO2 pressure (try dropping a small piece into an empty 2 liter soda bottle and put a balloon over the hole). Good luck