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Effect of Light Intensity on Photosynthesis!

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Okay so I'm doing my Bio IA right now and basically I put a blue filter on the lamp (because optimum photosynthesis takes place with blue light) and put 2 glass filters in front (to prevent the heating effect). In 5 test containers I put in algae balls with 5cm3 of hydrogen carbonate indicator and I've placed them at different distances from the lamp - 0, 5, 10, 15, 20cm. However, it's been a day so far but the colour of the hydrogen carbonate indicator of the closest test (0cm) container and the furthest test (20cm) container is really, really similar! It's meant to be really different right?

This is such a fail! Am I doing something wrong?!

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Guest 1529

Okay so I'm doing my Bio IA right now and basically I put a blue filter on the lamp (because optimum photosynthesis takes place with blue light) and put 2 glass filters in front (to prevent the heating effect). In 5 test containers I put in algae balls with 5cm3 of hydrogen carbonate indicator and I've placed them at different distances from the lamp - 0, 5, 10, 15, 20cm. However, it's been a day so far but the colour of the hydrogen carbonate indicator of the closest test (0cm) container and the furthest test (20cm) container is really, really similar! It's meant to be really different right?

Urgghhhh! This is such a fail! Am I doing something wrong?!

The thing is that the chloroplasts absorb every wavelength except for the green one and actually, the peaks of absorption are red AND blue (not only blue). Thus, you're limiting the amount of wavelength that reaches the chloroplast. And by that, it means that the electrons may not be sufficiently excited to go to the upper energy level as it's supposed to (you'll know what I'm talking about if you've studied photosynthesis...)

However, it should give different colours supposedly. You should try simpler experiments which you know that WILL definitely give the results you're expecting. Still, you can go on and see if anything happens and if not, you'll conclude that only blue light is not sufficient for photosynthesis

Did this help you? :)

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Okay so I'm doing my Bio IA right now and basically I put a blue filter on the lamp (because optimum photosynthesis takes place with blue light) and put 2 glass filters in front (to prevent the heating effect). In 5 test containers I put in algae balls with 5cm3 of hydrogen carbonate indicator and I've placed them at different distances from the lamp - 0, 5, 10, 15, 20cm. However, it's been a day so far but the colour of the hydrogen carbonate indicator of the closest test (0cm) container and the furthest test (20cm) container is really, really similar! It's meant to be really different right?

Urgghhhh! This is such a fail! Am I doing something wrong?!

The thing is that the chloroplasts absorb every wavelength except for the green one and actually, the peaks of absorption are red AND blue (not only blue). Thus, you're limiting the amount of wavelength that reaches the chloroplast. And by that, it means that the electrons may not be sufficiently excited to go to the upper energy level as it's supposed to (you'll know what I'm talking about if you've studied photosynthesis...)

However, it should give different colours supposedly. You should try simpler experiments which you know that WILL definitely give the results you're expecting. Still, you can go on and see if anything happens and if not, you'll conclude that only blue light is not sufficient for photosynthesis

Did this help you? :)

Thank youuu! That actually did explain a lot and I ACTUALLY understood! haha I continued with the experiment and I got SLIGHTLY different colours by the end of the day. I used the colorimeter to measure the absorption and as the light intensity lowered, the absorption levels lowered too, very slightly, but when i put the solutions in the cuvette, you could see the gradual colour change.

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Guest 1529

Okay so I'm doing my Bio IA right now and basically I put a blue filter on the lamp (because optimum photosynthesis takes place with blue light) and put 2 glass filters in front (to prevent the heating effect). In 5 test containers I put in algae balls with 5cm3 of hydrogen carbonate indicator and I've placed them at different distances from the lamp - 0, 5, 10, 15, 20cm. However, it's been a day so far but the colour of the hydrogen carbonate indicator of the closest test (0cm) container and the furthest test (20cm) container is really, really similar! It's meant to be really different right?

Urgghhhh! This is such a fail! Am I doing something wrong?!

The thing is that the chloroplasts absorb every wavelength except for the green one and actually, the peaks of absorption are red AND blue (not only blue). Thus, you're limiting the amount of wavelength that reaches the chloroplast. And by that, it means that the electrons may not be sufficiently excited to go to the upper energy level as it's supposed to (you'll know what I'm talking about if you've studied photosynthesis...)

However, it should give different colours supposedly. You should try simpler experiments which you know that WILL definitely give the results you're expecting. Still, you can go on and see if anything happens and if not, you'll conclude that only blue light is not sufficient for photosynthesis

Did this help you? :)

Thank youuu! That actually did explain a lot and I ACTUALLY understood! haha I continued with the experiment and I got SLIGHTLY different colours by the end of the day. I used the colorimeter to measure the absorption and as the light intensity lowered, the absorption levels lowered too, very slightly, but when i put the solutions in the cuvette, you could see the gradual colour change.

Oh and just one more thing to add: maybe, the distance to the source does not have that much effect because of the blue wavelength itself. Blue light is one of the strongest waves from the range of wavelengths so if you did for example for red, it would definitely give much greater differences as red waves are more easily deflected and dispersed ;)

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Okay, so now i'm stuck again...

I have 5 pieces of data and then two more repeats and I've calculated the average, standard deviation. Now what? Do I just plot it on a graph? Because I can't do a t-test because I only have one variable... what other tests can I do to further process my data? I'm so confused! I've finished Design, most of DCP and now i'm stuck! It's all due in tmrw! SOMEONE HELP?!

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Guest 1529

t-test is used to compare means so you can do ;) and you can do mean validation. Use the means you got for each treatment to plot a general graph. But before that you can plot the graph for each treatment using the means for each set of repeats and that's how you finish DCP ;)

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