# A box Under Air Pressure -- will it blow?

• MichaelT17
In summary, the author is working on constructing a hospital for sick trees. He is considering using pressure to increase the growth and healing of the trees. He is concerned about the potential for the pressure to blow the box apart. He has attempted to solve the problem with math, but thinks it may be too expensive to build. He is considering using an open ended tube filled with water as a safety valve.
MichaelT17

## Homework Statement

I'm doing a personal project to keep me busy for the winter. I grow Bonsai and I'm making a hospital for sick trees or recently collected ones from the wild that need to recover. I have constructed a 40x40 inch plywood box, 5/8 inch thick walls, air tight. The lid will be made of an Acrylic sheet (not purchased yet) to let light in from the outside. It will be a sealed controlled environment inside. Co2, O2, humidity temp levels etc will be controlled and measured.

I am considering putting the box under pressure for an experiment so see if it effects growth and healing. I am no physicist, I spent 7 years as a machinist so I can build. However, advanced calculations are not my thing :) I do not want to pressurize anything without knowing if its safe, and I don't want to spend too much money. So if materials are to much cost to put it under 15 PSI I won't bother and just stick with controlled CO2 etc... I was thinking 15 PSI just to double atmospheric pressure (AP) and see the results...

My logic

if AP is 14.7 PSI at sea level to double the air available to the surface level of the foliage of a plant I woudl have to put my box at 14.7 PSI (or 15 to round up...) How much pressure can a 40x40" 5/8 plywood box with an acrylic lid actually hold... maybe I could try 7PSI and just up it by 50%...

My Math
My attempt at a math solution was 40"x40"= 1600 square inches 1600 x 15PSI= 24,000 lb or 12 tons... That seems like to much for my construction. But maybe those numbers are relative to something I'm not thinking about...

Should I even bother with this idea and stick to simply producing greater amounts of CO2 and o2 without pressure as a factor? When I worked in a shop 15 PSI was not much at all, if I didn't have a wife and kid I would just do it and see if it blows up (from far away ;) ). But now its best I do the responsible thing and ask someone and save a trip to the dog house hehe.

I think your math is correct. 15 PSI will blow it apart. 1-2 PSI is probably all it will be able to stand.

CWatters and Chestermiller

Thanks guys, Haruspex, I have seen only a few studies on plant growth under pressure as the article says, its not something many people have looked at. I have developed methods for increasing the C02 organically and that certainly has a major impact. Mixing that with higher pressure is something I will try just not with this set up. I will move the idea to a 55 gallon drum reinforced and start with 5 psi and see the results and if its worth it to move to more expensive set up. So far any study I have seen that puts living organisms under pressure has had some positive effects. I can only hope it increases the survival rate of my trees :)

MichaelT17 said:
40x40 inch plywood box

So the area of a side is 1600 sq inches. At 1 atmosphere the force on that side would be 1600 * 15 = 24,000 lbs !

Plywood is frequently used as shuttering when casting concrete. Google found a table of recommended maximum pressures for that application. See Table 3 here..

Assuming I have interpreted that table correctly then it recommends limiting the pressure to below about 110lbs/sqf (5/8th ply with bracing every 16-20 inches not 40 inches). That's equivalent to a PSI of only about 0.7 psi. This limit might be to might be based on limiting distortion rather than burst strength.

I think I would use an open ended tube filled with water tube as a combined pressure gauge/safety valve. (eg over pressure pushes the water out of the tube reducing the pressure).

## 1. What is the purpose of putting a box under air pressure?

The purpose of putting a box under air pressure is to see how the box and its contents will react under different levels of air pressure. This can help scientists understand the effects of air pressure on objects and materials, and can also be used for testing the strength and durability of certain products.

## 2. How does air pressure affect the box and its contents?

Air pressure can affect the box and its contents in various ways. As the air pressure increases, the box may start to compress and may eventually burst. The contents inside the box may also be compressed or may experience changes in temperature due to the increased air pressure.

## 3. Can a box withstand high levels of air pressure without blowing?

It depends on the strength and durability of the box. Some boxes are designed to withstand high levels of air pressure, while others may not be as strong and could potentially burst. The materials used to make the box also play a role in its ability to withstand air pressure.

## 4. What are the safety precautions when conducting experiments with a box under air pressure?

When conducting experiments with a box under air pressure, it is important to follow proper safety precautions. This includes wearing protective gear, working in a well-ventilated area, and carefully monitoring the air pressure levels. It is also important to have a plan in place in case the box does burst.

## 5. What can we learn from studying a box under air pressure?

Studying a box under air pressure can provide valuable insights into the effects of air pressure on objects and materials. This information can be used in various industries such as aerospace, engineering, and manufacturing. It can also help scientists better understand the behavior of different materials under different levels of air pressure.

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