Very good description and use of pictures......even for high school students. Seems a bit young for their age, but it was that reason why they were interested I feel........took them back to their younger years plus the fact that the voice was clear and smooth......very easy to follow and listen to. This was not like many other videos on KZbin that have the speaker going 100 mph and is all over the place trying to be funny. Great information and straight to the point.