How do you measure the amount of photosynthesis taking place

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I originally wanted to measure either the amount of oxygen there is, or the energy given from the glucose (because of the photosynthesis equation), but I could not find any cheap solution to measure oxygen in a given amount of air, so I was wondering if it is possible to measure the amount of carbon dioxide instead. Does it relate inversely with the amount of oxygen and would it be an alternative measurement? Or is there a cheap and effective way to measure the oxygen level in the air?
Thanks

[Ceal Craig]

I originally wanted to measure either the amount of oxygen there is, or the energy given from the glucose (because of the photosynthesis equation), but I could not find any cheap solution to measure oxygen in a given amount of air, so I was wondering if it is possible to measure the amount of carbon dioxide instead. Does it relate inversely with the amount of oxygen and would it be an alternative measurement? Or is there a cheap and effective way to measure the oxygen level in the air?
Thanks

This is a bit out of my area of expertise, but here are some ideas for you to consider...

This article discusses doing this with certain devices, but I'm guessing those are expensive
http://ag.arizona.edu/azaqua/Biosphere/ ... esppap.pdf

These also discuss alternative measurement approaches: http://www.newstarget.com/005139.html
http://www.uow.edu.au/science/biol/phis/phis_fl.html
http://spot.colorado.edu/~basey/whorley.html

This one might just be helpful:
http://experts.about.com/q/1353/2721968.htm

Do you think you might be able to get access to a local college lab? That's one thought...

Best wishes

[Ceal Craig]

FOund another site that described more what I was looking for, with a water bath making use of the concept of volume displaced.

http://www.netl.doe.gov/coolscience/res ... &a_99.html

Look at the bottom of that page.

[jessicahua]

Hi!

This is also out of my expertise. I always thought that to measure carbon dioxide and oxygen, a person would need expensive equipment. However, I looked up some sites, and I found one. Hopefully it will help:

measuring CO2:
1. http://www.woodrow.org/teachers/esi/199 ... ingCO2.htm (I'm not sure if you can purchase the needed supplies)

Also, what do you consider expensive? I saw some oxygen meters that were $8-$25 on ebay. However, I have never done this before, so I am not sure if these are accurate, but at least they are a lot cheaper than the $995 one. Hopefully I helped and didn't confuse.

[phamlinh]

Hi there,

This is a bit out of my field as well, but I was thinking about it for a while. I know that the standard method involves using an electrode to measure dissolve oxygen.

I did a google search though and found a few relevant hits. If you're working with aquatic plants, you can measure the amount of oxygen released into the water by sequestering the plants in inverted funnels and such. Here's a relevant website:

http://www.madsci.org/posts/archives/oc ... .Bt.r.html

Alternatively, you may design your project using a photosynthetic microbe like plankton. Just in case you're interested in this (and in case any other interested parties view this post):
http://mscserver.cox.miami.edu/MSC23205/primaryprod.htm

However, I think this is probably the most relevant website. You can cut off leaf disks and measure the amount of oxygen released in an inverted tube that is kept underwater.

http://biowww.clemson.edu/biolab/PHSdisk.html

I hope this was helpful. If you have any other questions, please post.

Best wishes,

Linh