Oxygen for elders

[Judith]

Elders often need oxygen. What if they sleep in a room full of plants? Would that help? What equipment is needed to test the oxygen production of plants?

[hiramuzammal]

Here are two sites that explain how to measure oxygen content in the air:
https://www.sciencebuddies.org/mentorin ... p004.shtml
http://www.pbs.org/wgbh/nova/teachers/a ... erest.html

You could probably test the amount of oxygen content in the air before you add plants to the room and then test again after you add plants. I'm not sure if there will be a major difference in the oxygen content, though. And keep in mind that there will be many variables in this type of experiment.

Good Luck.

[carolinethorn]

Hi Judith,

This is an interesting idea. And its always good to do a project on something that you have a personal interested in.

Perhaps you could look at different species of plant to see which generate the most oxygen. While it can be difficult to measure the difference in oxygen content in a large space such as a room, if the volume of air is smaller it would be easier - so you could put the plants into plastic bags to trap the oxygen to meaure it in the way those links describe. For your background work you would want to research what times of day that plants generate the most oxygen and which plants might generate more than others based on leave characteristics etc. You would also want to think about why the room size or bag size makes measuring oxygen difficult or easier and diffusion of gases. Also think about what other gases that plants generate. And also find out how much oxygen a medial device can deliver to an elder that uses oxygen therapy.

Best of luck,
Caroline

[deleted-71576]

Oxygen concentration can be directly read by a number of devices, but they will be cost prohibitive. Besides, in a space as large as a room that is not airtight (and rooms aren't airtight - otherwise you'd die from lack of oxygen once you used it up), the concentration will almost undoubtedly be the same as everywhere else -- essentially 21% oxygen at sea level.

Using an enclosed smaller space, like a bag, is certainly a better approach, and will likely reveal measurable results.

Nice idea for a project. Have fun doing your experiment.

[kathrynshewey]

Hi!
This seems like a great idea for a project, especially since you have an interest in the subject. i would suggest researching first what types of plant produce the most oxygen and then using those plants in your experiment measuring the oxygen rate in the room with an elder with plants and then with out plants. keep in mind there will be many variables in this project, such as the type of plants used, as well as health conditions of the patient. good luck with your project!

[deleted-71555]

When I was in childhood I remembered a book said some plant obsorbes CO2 at a certain time of the day and exchange you the O2, but may actually releases CO2 during sometime at the night. Not sure if this info is true or this would help, but studying the O2 density at different time of the day / night would also be necessary.

Just one cent of my thought ...

[Judith]

Thanks for the responses about oxygen for elders. I put the test tube set-up in a box and put it in a plastic bag. The control test showed 20% oxygen. But adding plants in the box didn't seem to make a difference. Do I need to put plant cuttings in the water that is under the test tube? And the test tube set-up did not work at all last night when I added a different plant. It didn't register any air. It seems as if this process (suspending a test tube with steel wool in it) is not very accurate. Are there any other ideas? Thanks again.

[deleted-71576]

Tell us some more about your experimental setup. You mention putting plants in a box.

What sized box?
Was the air in the test tube obtained from that box????
Was the box airtight?
Was the plant subjected to daylight? How many hours. When was the air sample obtained??

[carolinethorn]

Hi Judith,

Any difference you see are going to be very small. It will be difficult to measure them using your equipment, if you can get hold of a digital meter that would help but those are expensive so its worth persevering with yor experimental set up and trying to optimize ways that you might be able to see a difference. Remember - even if you get negative results at the end of your experiments (ie. you don't see a difference between the bag with the plants and the bag without) the journey of how you got there and the scintific reasons for why you tried different manipulations of the conditions are what the science fair judges will be interested in.

.You may have to manipulate the conditions in several ways to be able to see a change - by this i mean leave the plants in the bag for an extended period of time but also you will need to fool the plants into producing oxygen predominantly and not carbon dioxide. WHat did you find out from your background research about what times of day and night plants release oxygen compared to cabon dioxide (if you didn't find that out yet, try searching that now on wikipedia by looking up photosynthesis )

WHen you have figured out if night or day is when plants release more oxygen - then can you come up with a way to fool that plants? How might you simulate conditions that are like night? or like day?

best of luck,
Caroline

[Judith]

I put the project in a file folder sized box...not too small or too big. It is in a plastic garbage bag that is taped shut. But not air tight I'm sure. The experiement tests the air in the box. But really it tests the air in the test tube doesn't it? So how do I get the plants to let off oxygen to get into the test tube? From the experience of the past few days, it seems that the changes happen at night.

[Judith]

I forgot to say that we live in the mountains at an elevation of 6000 feet. Is that what is causing problems in this experiment?

[deleted-71576]

This starts to get into an area of fascinating physiology, but somewhat complicated explanations. At 6000 ft, the concentration of oxygen in air remains at 21%. It remains that at the top of Mt. Everest also. Air is air.

Atmospheric pressure and inspired oxygen pressure fall roughly linearly with altitude to be 50% of the sea level value at 5500m and only 30% of the sea level value at 8900m (the height of the summit of Everest). A rule of thumb is that the pressure drops about 1 inch of mercury for each 1,000 foot altitude gain. At your elevation, the atmospheric pressure will be about 80.1% of that found at sea level. (Yes, I know I am liberally using both English and Metric measurements. Sorry.)

But the partial pressure of oxygen in your lungs (and what your brain and other organs receive) goes down as the atmospheric pressure goes down with altitude. This has dramatic effects on human respiration, and human physiology in general but your iron oxide reaction will still see the same relative concentration of oxygen.

The reaction would proceed more slowly, however.

[deleted-71447]

I don't see why you would have more problems at high altitude than at low altitude. The proportion of oxygen in the atmosphere does not vary much with altitude. (Rather, the total number mass of air per volume decreases as altitude increases). Also, as long as you compare your results with plants to your results without plants, the proportion of O2 in the air shouldn't be a problem.

I believe the setup you are using can be made to work for your experiment, but it will probably take some trial and error. For other experts who haven't seen the test tube & steel wool method being used by Judith (I think), it is described here:
https://www.sciencebuddies.org/mentorin ... p004.shtml(bottom of page)

There are a few things you can do to improve your odds of success. First of all, for better precision in your measurements, you will want to have the largest possible rise in water level. A tall, narrow tube will have a larger change in water level than a short, wide tube, so use tall narrow tubes if you can.

Secondly, even if you do a near-perfect procedure, there will be some variability in your measurements. This can be overcome by analyzing many replicates of each air sample. The more replicates you analyze and measure, the more likely you will be able to see subtle differences between the O2 concentration with and without plants.

Thirdly, variations in temperature and barometric pressure can affect the height of water in your tubes. If you measure the O2 concentration in the enclosure without plants on one day, and then measure the O2 concentration in the enclosure with plants two days later, it will be difficult to tell whether differences in water level result from actual differences in O2 concentration, or changes in barometric pressure, temperature, or some other factor. To overcome this problem, I would suggest analyzing all your samples at the same time. You could build two enclosures, one without plants and one with plants.

Good luck!

[deleted-71555]

One important thing you should keep in mind is that plants exchange CO2 to O2 under PHOTOSYNTHESIS, and this needs LIGHT. In other words, this may not happen during the dark night. So be careful if this is a real practice for the elders. The below article actually says the plant may take in O2 during night to maintain it energy:

During the night, the plant actually uses oxygen it has left over from the daylight photosynthesis or takes the oxygen from the air surrounding the plant to meet its energy needs.

http://www.newton.dep.anl.gov/askasci/g ... n01854.htm

[deleted-71576]

You can fill a room to overflowing with plants with an elderly patient at 6000ft altitude and not compromise their health at all at night (unless they are allergic to them or immunocompromised.)

Don't want to give away your results before you get them, but don't worry about any risk to human health with this. There isn't any.

[Judith]

The results after testing 3 plants for 24 hour periods is that the oxygen was LESS when plants were in the box. It was 10% oxygen in the box as opposed to 20% with the control test. What's happening? I wrote it up that it might be a lack of time...needs more than 24 hours. Or it could be the time of day...took the test out at 10 am. or ...it is barometric pressure? Interpreting the results is hard.

[deleted-71576]

That's how science goes sometimes. Unexpected results. A plethora of variables that are hard to control.

Keep your testing period during daylight hours. That eliminates the daytime / nightime issues.

Record the barometric pressure before and at least on a few occassions during each measurement. If it varies significantly, you will have to discard that measurement.

Make sure the temperature in the room stays as constant as possible. Otherwise the partial pressure of gasses over the liquid will change.

Or, perhaps there was just artifact and if you did a larger series of experiments you would get good data.

Make as many extraneous variables constant as possible, then repeat your experiment a larger number of times (e.g. 10 times). Let us know what happens.

[deleted-71447]

Is it possible that your steel wool is getting all used up before all of the oxygen reacts with the iron? That will result in false low readings. Also, if the steel wool dries out before the reaction finishes (or is dry to start with), the reaction will proceed very slowly.

[Judith]

I typed a message but don't know if it went through. I wanted to tell everyone who helped me with my science project that I won Grand Champion. Thanks so much.

[deleted-71576]

Congratulations. Very well deserved, I'm sure.

So what results did you find? Problems with doing the experiment, etc.

A little feedback would be nice if someone else tries a similar experiment in the future.

After you tell us what you found, I'll tell you why you don't see rooms full of plants with elderly patients in hospitals and nursing homes.

[Judith]

I put three different plants in the box--one at a time for 24 hours. The first was cuttings in water. The results were 20% oxygen--the same as the control or maybe a slight elevation. The other two were plants in soil and they tested at 10%. It seems that the soil may give off some methane? Or it may be that these plants didn't get enough light to do photosynthesis. I ran out of time to try different possiblities.

[deleted-71447]

Congratulations, Judith. Thanks for telling us about the outcome.

[deleted-71576]

Judith:

I think that the plants didn't get enough light to have significant photosynthesis. That would be my guess.

There are a number of reasons why this doesn't work in real life. The most important one is that rooms aren't air tight. The air in a room exchanges several times an hour with outside air. The air exchange rate is much greater than the amount of oxygen production from the plants. So the concentration of oxygen in the room always remains the same, about 21%. In operating rooms, the air exchange rate is 20-40 room times per hour. It's amazing how people, even people who should know better, don't realize this.

When there was the Anthrax scare after 9/11, some government official (FEMA, I think), told people to prepare an airtight room with duct tape and plastic sheets in case of a gas attack. If the room was truly airtight, your body would use up all the oxygen in the room and you would die of lack of oxygen. The nerve gas wouldn't need to get to you, you would have done yourself in. And this was our government telling us this. Amazing.

An elderly person probably uses about 200 - 250 ml/minute of oxygen per minute. It would take massive amounts of plants to produce that much, and besides, it would leak out anyway.

The second reason is that elderly people can become somewhat immunosupressed by diseases (it's rotten to get old). Some plants can spread some bacterial diseases. So ICUs in hospitals don't allow plants, even though everyone wants to bring in flowers to brighten their days.