This video is very short: only 5 seconds long. If you don't know how to play it, see the instructions at the bottom of the page.
This funny video shows two of my students goofing around with the "lie detector." One is holding onto one one wire, the other student is holding onto the other wire. When they touch the other's skin (in this case, face) the electronic kit screeches (did I mention it's pretty loud?). Depending on how hard they push and some other factors determines how well they conduct electricity, which varies the pitch (they don't actually feel electicity at all).
If you have a fast internet connection, you should be able to simply point and click to play the short MPEG movie. If the picture is halting the first time through, click play on your media player and it ought to play smoothly the second time.
You will almost certainly have to hit play a second time if you have a dial-up internet connection. If you still can't get it to run smoothly, you will have to right-click, then "save file as..." or something similar to that. Take note of where you are saving it. They are short and highly compressed, so they won't take long to load. Even with a fast connection, save the file like that if the picture is jerky. To play the file, find it and double-click on it. It will play in the default media player.