More Extra Credit for College Algebra

Saturday September 14, 2019

•  college algebra •  extra credit •  math education •  UMGC • 

I have written a new extra credit problem for my college algebra students!

Hello, everyone. We’re getting to that point in the semester when students start asking the question every professor hates: Can I get extra credit? Now, I will say something really important here and that is I do not like extra credit at all. Most of the time, the question could be rephrased, “Can I attempt extra work and get more credit for it?” like we’re talking about a prison term. And the answer to that is no, not really. Never.

But. I really like the idea of extra credit when the work is something above and beyond the course material. When it is something that truly expands on what you are doing. When it’s something, you know, extra.

And I think I have a good one. Watch this video of 8 amazing fire tricks.

8 AMAZING FIRE TRICKS (do not try at home, lithium & boric acid fumes are toxic)


If the embed does not work, you can click here for the entire video. From 1:22 to 1:32, there is a pool of blue water and a floating candle that is burning. A clear glass is placed over the candle so that it is in the water and the candle is isolated. Eventually, the candle goes out as we might expect…and the blue water level under the class rises!

The extra credit question is, how high will the water rise?

There’s a lot of assumptions we need to make to figure this out. I am going to kick off some off right here:

  1. Assume the glass is a perfect cylinder.
  2. The mouth of the glass has a diameter of 10 centimeters.
  3. The height of the glass from the water-level to the top of the glass (which, since it is upside down, is really the bottom) is 30 centimeters.

You may need to make additional assumptions…I haven’t solved the problem yet. If you need to make one, and would like assistance is making sure it is reasonable, feel free to ask. You should ask here, so that the assumptions made are common to everyone.

Now, there’s a lot of science and math that should go into solving this problem, but it does not require anything you would not have learned in either high school or this class. Again, feel free to ask any questions you need to right here, again, so everyone can benefit from the responses.

The extra credit project is due no later than the final exam due date. There is no specified form for the response, other than you must explain your answer, and that goes way beyond showing your work on this one. This will contribute up to 5 percent on your class grade.

Good luck, we’re all counting on you!

The image above is a still from the source video by Go Experimental.