Go to the Submit Questions link in Resources. There are many websites that contain information having to do with this popular television sensation, but the proper form for submitting an idea to the show itself can only be found at this site.
Scroll down the screen until you see a blue link that begins, "To send us your ideas..." Click on this link.
Scroll down the categories until you find the one that is closest to the subject matter you wish to submit. For instance, is the experiment you want to see aired on the show something that you've seen in movies? If so, click on the link "Ideas: Movies." There are brief descriptions beneath each link, so finding the right one should be easy.