This topic is now archived and is closed to further replies.


Is this Physics IA Lab Appropriate?


We are now getting started with our IA labs in SL Physics, however I'm not sure if the topic I've chosen is appropriate.

I have chosen to find the correlation between the time needed for a coffee filter to drop from a certain heightand its mass (increased by adding washers to the inside of the filter). I was going to focus on how the increased mass would lead to increased acceleration and speed.

Is this experiment too simple for an IA design lab? Or does IB simply grade you on the basis of how well you identify variables, perform an experiment in an organized fashion, and be able to understand errors made?

I was also considering adding an element of air resistance to the experiment, mainly: As the speed of the filter increases, it begins to distort (by bending inwards) and encounter less air resistance, increasing its speed further.


Share this post

Link to post
Share on other sites

Honestly, from my personal experience, now in my 2nd year of HL Physics, the most important thing is to examine the relationship between two variables, which is exactly what you're doing. You are not graded on the complexity of your experiment.

Now, that was the answer to your question, the rest is just me rambling about physics labs, and coffee filters, and things I'd do, so read it if you like :P

I'll also tell you, your specific idea is perfectly fine, and is actually similar to one that we did. Now, one thing that I will recommend is to be careful with air resistance. The actual models for air resistance are extremely complicated, because of the calculations of surface area, shape, which involve some advanced mathematics.

Essentially, varying m of the coffee filters by stacking multiple ones inside each other will be better, as it won't alter the shape or surface area, allowing you to do a relationship with mass to say, acceleration or terminal velocity, or anything else, without having to account for varying air resistance (there will be some, but it is minimal enough to where as long as you state it, you can assume it constant.)

This could allow you to find other things as well, say a constant to define the density of the air, in relation to the (reasonably) constant shape of the coffee filter, with different mass (using the above stacking method).

Not sure if I can give out my ideas here... if not, a mod can message me and I'll edit this out, but with the above you could look at something like terminal velocity, by simplifying an existing model, to include constants for your specific experiment.

So, while you may have 4 variables in the actual equation, several will remain constant since you aren't changing shape, or the air, so that you could rewrite the equation to include 1 or 2 constants

say v = (a)(m)^(b)

where a and b are constant relating to the shape of the coffee filter, subsequently, its air resistance, the density of the air, and gravity (those are pretty much the variables of terminal velocity :P)

then you could find your own defined variables by measuring v and m and processing data.

Just thinking of ways you can bring in some cool concepts (air density, shape) without having to do some crazy calculations, since you seemed to want to do that.

But that's a pretty advanced lab, and I'm really just playing around with ideas here, if you're crunched for time, your original idea (aside from the washers) will be perfectly fine.

Anyways, food for thought. In summary though, your idea is definitely a good one for a lab, especially one where you have to come up with your own design.

1 person likes this

Share this post

Link to post
Share on other sites