From the very early days of Science.Ars, Ars readers have helped shape our science coverage. In general, you ask great questions and when it comes to some topics, you know much more than we do. Your participation helps make the discussions—both at Nobel Intent and in The Observatory—educational for everyone. So it's our great pleasure to announce that we've got a new way for you to contribute your science-fu to the site, and maybe take home a fantastic prize or two in the process.

Today, Ars embraces the age of moving images with the launch of Ars.TV, sponsored by Canon. To celebrate, we're holding a science video contest and will provide the grand prize winner with a Canon EOS 7D. Not only does the EOS 7D shoot great video, it also happens to be a fantastic DSLR. The grand prize winner will also score a Premier subscription to Ars. A runner up will take home a Best Buy Gift Certificate worth $500 as well as a Premier subscription.

Your mission (should you choose to accept it) is to use video to explain a scientific concept in terms that a high school science class would not only understand, but actually be interested in watching. The videos must be short (less than three minutes long) and should take advantage of the medium. No narrated PowerPoint presentations—we want your images to move!

To give you some ideas on how to make a compelling science video out of material you probably already have, we've had John Pavlus, who makes science videos for a living, provide us with an example. Enjoy, and pay attention to the tips he provides throughout the clip.

Entropy and the arrow of time.

We'll choose an honorable mention entry from each of the three categories below, in addition to the grand prize winner and runner up. Entries will be judged based on three considerations: clarity, creativity, and of course, scientific validity. You need to submit your entry by December 25, 2010. Upload your video somewhere where we can nab it, be it Vimeo, Dropbox, your personal hosting; Youtube is OK if there's no other option. Anywhere we can download the full original video file would be best for our process.

The three categories are:

Bio: Anything's on the table, from biochemistry to evolutionary biology and ecology. Some ideas to get you started: photosynthesis, deep brain stimulation, speciation, the RNA world, defining consciousness, protein folding, PCR, and synthetic biology.

Physical: Physics underlies most of modern science, from geology to astronomy, so this category covers a lot of ground. Some examples: thermodynamics, the carbon cycle, time dilation, flood basalts, quantum tunneling, superconductivity, red shifts, the double-slit experiment, the black hole information paradox, dark matter, squeezed light, and neutron stars.

Math: Math is a powerful tool to help us understand the natural world, and has become a method of defining worlds—like those of string theory—that we may never be able to observe directly. Some math concepts that might make for good video explainers: higher dimensional geometries, imaginary numbers, exponential growth and decay, Turing machines, Godel's incompleteness theorem, P vs. NP, cellular automata, and the invention of the calculus.

The contest is open only to legal residents of the 50 United States, the District of Columbia and Canada (except the Canadian province of Québec) who are at least 18 years old as of the date of entry. You can check out the full set of contest rules here.

I'm really excited that science was chosen as the topic for our first video contest, and even more excited to see what our readers can come up with. Fire up the cameras and get down to it.