I always thought that lightning rods attracted and grounded lightning strikes. An engineer I work with, who happens to be somewhat of a static expert, told me that lightning rods are actually supposed to prevent strikes by grounding the ions in the air that are around a house, since it is the positive ions that attract the negative electrical charge from a strike. He also made the point that the amount of current in a strike would completely melt any guage rod and ground cable making them pointless for that purpose. Is any of this true?
Unauthorized access (hacker) Introduction of virus Untrained employee causing errors
There's no easy answer to this. Really, you can't have 90 students saying something to the class as a whole, because there isn't time. But are you still mostly lecturing? You can do pairs and groups even in a large class. You can give questions to discuss, and then call on one person from one group randomly to give the group's answer. This means that everyone in the group has to make sure than every member has the right answer so the group won't be embarrassed when they are called on. You can ask quick yes-no questions and have them respond with thumbs up or down, or with response cards- green for yes, red for no. If your school promotes technology, you can get those clickers where students can make a choice among answers after they have discussed them. You can give written questions, have them discuss and turn in one answer page per group, with all their names on it. If they are in groups of 4, that gives you about 20-24 pages to look at. If you walk around while they're working, you can monitor who's there and whose names are on the page.
