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Restrictions on the choice of an IA topic? Does it have to involve dependent and independent variables?

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My teacher told me the biology ia has to involve the variables. i.e. the investigation must be about the effect of sth on sth. That doesn't sound right to me. Isn't it supposed to be an exploration related to ANYTHING we've covered in the course? I want to do an identification of lactobacilli in yogurt by DNA profiling. Is it possible that my teacher is mistaken? 

What about other restrictions on the choice of topic? DNA profiling tech is unavailable in my school lab. Is it ok to use more advanced equipment in outside labs? Or would it be considered beyond our level or even academically dishonest? 

Or, does it have to be a lab experiment at all? I heard about someone doing polygenic traits with computer simulations. Is that also acceptable? Could it be disadvantaged compared with a lab experiment and receive a lower score? 

P.S. How much time should I spend on my IA in all? I know the guide says 10 hrs but does it take longer in practice if I'm looking to achieve higher scores?

Edited by KATHERINEwjw

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I should say I did not take biology in IB.

In general it is easier to score higher marks when your have clearly defined independent variables and apply a t-test. What you can do in separations is to compare two methods in terms of their yield/selectivity/quantities recovered, efficiency, set up time/resources, and whether it destroys the sample in the process. 

Same for simulations. Simulations are very hard to score high marks because it is difficult to show personal input in setting up the experiment or understand assumptions of the model/simulation. It is also difficult to suggest follow-up experimentation. 

The school should not prevent you from seeking outside lab as long as you can assure them that you will be the one conducting the experiment, safely.

10 hours is enough (say 3 hours experiment 7 hours write-up) if you have enough experience in writing lab reports and understand the background information before the experiment. When you consider time to do research on techniques or background or to just think of the content to write, it could be 15-20 hours if you are unfamiliar with report writing and/or the topic.

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5 hours ago, kw0573 said:

I should say I did not take biology in IB.

In general it is easier to score higher marks when your have clearly defined independent variables and apply a t-test. What you can do in separations is to compare two methods in terms of their yield/selectivity/quantities recovered, efficiency, set up time/resources, and whether it destroys the sample in the process. 

Same for simulations. Simulations are very hard to score high marks because it is difficult to show personal input in setting up the experiment or understand assumptions of the model/simulation. It is also difficult to suggest follow-up experimentation

The school should not prevent you from seeking outside lab as long as you can assure them that you will be the one conducting the experiment, safely.

10 hours is enough (say 3 hours experiment 7 hours write-up) if you have enough experience in writing lab reports and understand the background information before the experiment. When you consider time to do research on techniques or background or to just think of the content to write, it could be 15-20 hours if you are unfamiliar with report writing and/or the topic.

Thank you very much! This is helpful with both my biology and chemistry IAs! One thing though, my biology teacher said he had a student who got a high score with simulations in genetics. 

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Certain approaches do not necessarily restrict your maximum marks, but only make it more difficult to get high marks. Other subjects may however specify that not meeting certain conditions may restrict a criterion to a maximum of such and such. 

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On 5/28/2018 at 5:50 PM, KATHERINEwjw said:

Thank you very much! This is helpful with both my biology and chemistry IAs! One thing though, my biology teacher said he had a student who got a high score with simulations in genetics. 

 

On 5/28/2018 at 12:18 PM, kw0573 said:

I should say I did not take biology in IB.

In general it is easier to score higher marks when your have clearly defined independent variables and apply a t-test. What you can do in separations is to compare two methods in terms of their yield/selectivity/quantities recovered, efficiency, set up time/resources, and whether it destroys the sample in the process. 

Same for simulations. Simulations are very hard to score high marks because it is difficult to show personal input in setting up the experiment or understand assumptions of the model/simulation. It is also difficult to suggest follow-up experimentation. 

The school should not prevent you from seeking outside lab as long as you can assure them that you will be the one conducting the experiment, safely.

10 hours is enough (say 3 hours experiment 7 hours write-up) if you have enough experience in writing lab reports and understand the background information before the experiment. When you consider time to do research on techniques or background or to just think of the content to write, it could be 15-20 hours if you are unfamiliar with report writing and/or the topic.

You said another suitable form of exploration is to compare different methods. Do I have to come up with a better method than the regular one taught in the text book? Is it okay if this new method is actually less efficient? 

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There could be multiple methods to separating DNA strands. Try look in a different textbook or search online. You could profile them the same method but separate them using different methods. You don't need to do anything groundbreaking. 

Hope that helps!

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1 minute ago, kw0573 said:

There could be multiple methods to separating DNA strands. Try look in a different textbook or search online. You could profile them the same method but separate them using different methods. You don't need to do anything groundbreaking. 

Hope that helps!

Thanks. but actually I was thinking about chemistry...e.g. distinguish between weak and strong acids through titration using indicators. 

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You can for example try distinguish between two weak acids of similar pKa, so for example in the old syllabus our teacher had like 20 unlabeled acids, gave one to each student, and assigned us to characterize them. I think it's somewhat trivial to distinguish between weak and strong acids. 

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5 minutes ago, kw0573 said:

You can for example try distinguish between two weak acids of similar pKa, so for example in the old syllabus our teacher had like 20 unlabeled acids, gave one to each student, and assigned us to characterize them. I think it's somewhat trivial to distinguish between weak and strong acids. 

I saw a sentence in my textbook saying acid strength CANNOT be distinguished with indicators, but I think it can and that's where I got the idea from. How can I distinguish between acids of similar pKa then?

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Acids of similar pKa should be distinguished by other tests for functions groups (eg Bromine water), melting point, solubility, etc. In a laboratory, this is done with NMR and Mass spec, as discussed in the HL course.

Indicators inform directly the pH range. 

You can go from pH range to pKa only if the concentration of acid and its conjugate base is known (Henderson-Hasselbalch equation), through a titration.

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On 5/30/2018 at 6:51 PM, kw0573 said:

Acids of similar pKa should be distinguished by other tests for functions groups (eg Bromine water), melting point, solubility, etc. In a laboratory, this is done with NMR and Mass spec, as discussed in the HL course.

Indicators inform directly the pH range. 

You can go from pH range to pKa only if the concentration of acid and its conjugate base is known (Henderson-Hasselbalch equation), through a titration.

I can also go from pH to pKa right? That's how I can determine the pKa of the acid. But how do I find the concentration of its conjugate base through a titration? Would the conjugate base need to be extracted and titrated separately? 

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You should read more about the equation. Your textbook should have practice problems. In any case you can go from pH to pKa if the concentrations are known. In general pKa of a weak acid or weak base is deduced using the half equivalence point (where acid concentration is equal to conjugate base concentration and log 1 = 0). This should be all in your book or online. Best luck!

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1 hour ago, kw0573 said:

You should read more about the equation. Your textbook should have practice problems. In any case you can go from pH to pKa if the concentrations are known. In general pKa of a weak acid or weak base is deduced using the half equivalence point (where acid concentration is equal to conjugate base concentration and log 1 = 0). This should be all in your book or online. Best luck!

Thanks for the advice! My textbook does not teach anything about the Henderson-Hasselbalch equation, but it does mention that pKa=PH at equivalence point. But doing this would be too simple an IA, so I'm looking for alternative approaches to determine the pKa...

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pKa DOES NOT EQUAL to the pH at EQUIVALENCE POINT. Water has pKa of 14. At half equivalence point pKa = pH. For water that is pH = 7. You'll find it online.

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5 hours ago, kw0573 said:

pKa DOES NOT EQUAL to the pH at EQUIVALENCE POINT. Water has pKa of 14. At half equivalence point pKa = pH. For water that is pH = 7. You'll find it online.

Right. Sorry. That was definitely a typo:0

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