Measuring rate of photosynthesis

[ronthepon]

Yes. Leaves do need . How would it be if I put the leaves under jars, with the bottoms of the jars dipped inside water?

Then I measure the oxygen evolved somehow.

UncleAl, I happen to be rather impatient at the moment, so I cannot try google surfing...

[UncleAl]

I happen to be rather impatient at the moment, so I cannot try google surfing

Six months in the lab will save you an afternoon in the library.

[InfiniteNow]

Originally Posted by sebbysteiny

correct me if I'm wrong, but doesn't photosynthesis require carbon dioxide gas?

I'd like to clarify that we cannot know if plants on other planets (come on, you know there are at least a few...) require CO2 for photosynthesis, nor if EVERY plant on Earth does.

[sebbysteiny]

I did a quick google search and I found the following link that might be useful.
http://waltonfeed.com/self/upack/oxyintro.html

The problem with your experiment is that there is very little %age of CO2 in air. Therefore, the photosynthisis will stop reletively quickly. Instead, might I suggest filling the jar with carbon dioxide. This isn't too tricky. Just add a large amount of carbonate to acid in a test tube filtering the contents into water. Obviously ignore the first few bubbles (because it's air) and then use the bubbles to fill up a jar full of water. Then put the plant in the upside down jar making sure the CO2 doesn't escape. But instead of a jar, use a measuring cylinder and also, make sure an oxygen absorber is inside too.

From what I've seen, oxygen absorbers only cost about £5 or something, and I'm sure your school will be prepared to refund the costs.

For bonus points, do you know which colour light will be the worst for photosynthasis?

[InfiniteNow]

Originally Posted by sebbysteiny

For bonus points, do you know which colour light will be the worst for photosynthasis?

Higher frequency... blues, purples, ultra-purples... causes heating and evaporation and probably some structural damage.


What do I get? Do I get a cookie? Can these bonus points be turned in for prizes? I want the hand-cuffs!

[Mercedes Benzene]

If you are able to choose the type of plant used, I think you could do this:

Get some sort of aquatic plant...
Put samples of the plants into jars or test tubes or something, submerged with water.
Put an acid indicator into the test tubes.
Blow Carbon dioxide into the test tubes through a straw (the color should change due to the presence of Carbonic acid in solution)
Put your samples under the different light sources.
Measure the rate of change of CO2 in the jars.

Not only will you see oxygen gas being evolved, but the indicator color will also change color!!
Just my idea... i don't know. GOOD LUCK!

[sebbysteiny]

What do I get? Do I get a cookie? Can these bonus points be turned in for prizes? I want the hand-cuffs!

Yes, you do get a cookie and some hand-cuffs too .......
but only if you were right first time!!

I'm sorry to say it but

try again

[sebbysteiny]

Get some sort of aquatic plant

Aquatic plants, now why didn't I think of that???? Genius.

Of course, you would have to make sure they could survive the acidic conditions of carbon dioxide water. Perhaps that indicator is a little unncecessary since you have a direct numerical rate of measurement by the amount of gas produced in the jar / measuring cylinder. Don't need to make the same measurement twice!!

[UncleAl]

I'd like to clarify that we cannot know if plants on other planets (come on, you know there are at least a few...) require CO2 for photosynthesis, nor if EVERY plant on Earth does.

Do you read what you write? What is the definition of photosynthesis? Do you have a way around terrestrial RuBisCO? Tell us.

Selaginella lepidophylla is astoundingly good at survival under adverse conditions, but its biology is otherwise unremarkable.

[ronthepon]

Green light is worst for photosynthesis. (the bonus point, please)

Now I am prepared to use a C4 plant, so there should be less CO2 lessness problem. Maybe I could have plenty of CO2 inside by burning something inside first...

I cannot do aquatic plants. They wont do.

Hmmmm... Oxygen absorbers... tell me what all you know...

Drat! can't go on google! Got 11 minutes before my coaching classes begin!