15-minute Presentations

You might want to read this article from Physics Today.

Guidelines for 15-Minute Talks

You must give a short presentation on one of the experiments you have completed so far in this course.  This presentation will be in the style of a short American Physical Society conference presentation.  You should prepare your talk as if you were presenting your research results for the first time to your colleagues. 

Talks should be 10-12 minutes long, with 3-5 minutes for questions at the end.

You may prepare your talk either using overhead projector transparencies, or using PowerPoint and a computer projector.  As a general rule, you should plan on speaking for about one minute per transparency or PowerPoint slide, so you will need about ten transparencies or slides.  You may obtain transparencies that will work in the lab laser printer, or color inkjet printers, or you can write (neatly!) on transparencies with markers, or both.  Tom Baldwin or Allen Monroe can give you transparencies for laser and inkjet printers, but make sure you ask for some early as they may run out!  If you decide to use PowerPoint, you must find a way to get your talk onto the portable computer w/projector before the beginning of class on the day you give your talk.  Tommy can give you access to this computer.  The computer is also used on MTW afternoons for 375 lab, so you may have to wait until after 3PM if you need it in the afternoon.  The computer will be available all of Wednesday morning.  You may put your talk online and download to this computer, or you may put it on a floppy or a CD.

Your talk should include the following:

Title slide.  You should say who you are, what experiment you will be talking about, and where the research was performed.

Introduction and background.  You should introduce the motivation for the experiment, and the theory behind the experiment you are doing.  For example, if you are talking about the Franck-Hertz experiment, you might explain that Bohr's model of the atom predicts that photons are emitted with discrete energies, which has been observed, but also predicts that atoms should absorb energy in discrete amounts, which is what you will try to show in this talk.  Then describe the theory of the Bohr atom, etc...

Experimental technique.  You should explain how your experiment works, especially the things that are unique to your setup.  For instance, there are lots of ways to measure the speed of light.  If you are talking about the speed of light experiment, you should outline how your apparatus works.  What aspects are particularly critical?  The accuracy/precision of the rotating mirror motor?  The angle of the beam splitter?  The path length?  The type of laser used?  Some of these matter a lot, some don't matter much.  Try to boil it down to the important parts. 

Analysis of the data.  What techniques did you use to analyze the data?  If you fit a line to two quantities, show this, and say why.  Does this help to eliminate a particular source of systematic error?  If you are finding a peak, say how.  For some experiments, analysis is critical.  For example, in the photoelectric effect, it is very important how you analyze where the stopping voltage is.  Show your technique and justify why you think it gives the correct answer. 

Results.  State the results of your experiment, and error. 

Error analysis.  How did you compute the error in your value?  What contributed the most error? 

Summary and conclusion.  Compare your result to the accepted value.  Does the experiment satisfy the motivation you outlined in the beginning?  How would you improve the experiment?  Or would you?  How might you improve your methods?  Some experiments have a weak point that causes the most error, and could obviously be improved.  Some experiments actually work well to demonstrate the physical principle which motivates them. 

The above order is a good guide, but it may not work for every talk.  Feel free to arrange the talk as you see fit.  You may choose to spend more time on one particular aspect of the experiment.  The basic idea is to convey why the experiment you did is interesting, and hopefully you will also convey that it was exciting.  Feel free to discuss your talk with the instructor or the TA before you give it!