This article in particular is more about telling you how to build an electronic gate.
This is an Internet assignment on the website How Stuff Works. The website offers articles about various topics. This is a list of questions for a particular article on the site. The link to the article is at the top of the page for the students. The click through the article to answer the questions. It takes one class period.
Check out my other listings under Computer/Technology
There is soon to be a Bundle for these items so please look for it.