**Keep it simple.**

You have been working on this problem for about a year, but many of the jurors just saw the problem today. These jurors need for you to first clearly explain the most basic physical principles at a level that a high school physics student could understand. Only after you have shown that you understand, and can communicate, the relevant fundamental physics, will they become receptive to your more nuanced analysis.**Use cartoons and toy models.**

In your presentation, illustrate the physics using your own drawings of your toy models. You should never have a slide with only words and equations.**Show diagrams and photos of your experiment.**

Make it clear how you took your measurements, without wasting time on less relevant details, even if you spent lots of time on these.**Never show an equation that you do not understand.**

It is common for students to look up a topic and write down an equation without understanding it. This usually ends with either the opposition, or a juror, asking about the equation and you looking very bad. It is much better to use a simpler equation, that you actually understand, than a more complicated one from some source.**Explain the physical principles behind all computer models.**

A computer is a powerful tool for iteratively solving complex problems using toy models and simple mathematics. The jurors care that you can explain all computer simulations in terms of their fundamental physics, using drawings and flow charts. Never say something like, “we used Euler’s method to solve this differential equation.” Rather, develop your own algorithm, based on the physics involved, and code it up yourself. Neither you, nor your audience, need care that you just solved a non-linear second-order differential equation. Again, explain the steps clearly using cartoons and flow charts in a way that any high school physics student would understand.**Use physical, not ad-hoc, models.**

An ad-hoc model is a mathematical model chosen because it fits the data. These can be quite useful in limited situations, such as interpolating between experimental data. However, ad-hoc models tell you nothing about the underlying physics, and their parameters have no physical meaning. Physical models, on the other hand, are derived from your physical theory. If you data fit a physical model, it supports the theory from which the model was derived. If the data deviate from the model, it means the physical model is either wrong or overly simplistic. So, you have not learned something.**Show units and error bars on all measured quantities.**

When you measure something, you need to find the errors in each measurement, and propagate these errors to obtain errors in your derived quantities, as I discuss in an overview of error analysis. Round your errors to one significant digit, and round the corresponding quantity to the same number of decimal places. This way you never display digits that are less significant than your margin of error.**Show your theory and data on the same graph.**

The best way to present data is graphical. A good graph should compare data to theory, and make a particular point. A good graph makes a particular point.**Prepare extra slides anticipating questions.**If you choose to skip some details because of time constraints, prepare extra slides in case you are asked. For example, say you took data using some machine, be prepared to explain how it works if asked. Similarly, if you wrote a computer simulation, prepare some slides that show a more detailed algorithm so you can answer those questions.

**Cite primary sources in context.**

Textbooks and encyclopedias are wonderful resources, but they are secondary sources. It is the convention in science to reference the first paper, or book, to have done the work involved. Since you are often referring to, or testing, some law of nature, you really should refer to, and cite, the original source if possible. A little bit of historical context makes for a much better presentation.

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