Recent content by Bonnie

I'm amazed how laser is used in medical practice. I wonder how laser can destroy a kidney stone while not affecting the other organs of the body where the laser passed through.

Is that applicable to all lasers? My son really likes to have one for Christmas so I'm trying to shop where I could buy it cheap but has good quality. How about the DinoDirect offers, are they good enough?

I feel very small after looking at that diagram. For me though, I think the universe is infinite so we really can't estimate the size of the universe.

Thanks for all the input, everyone! FYI, my youngers are 7 and 10, and I DO worry about them getting hold of whatever he gets. And I AM afraid they would use them as laser tag toys.

Good for you for wanting to know the "why" and the "how" of something most people take for granted. It is fun to pose a problem, then look for a solution. BTW, have you seen this site? How a Calculator Does Division That site also links to a page that discusses many different rounding...

My oldest son is turning 13 this year, and would give anything for his own laser. What would be a good one for him to start with? (Preferably something that he can't use to blind the dog or burn down the house...)

Wouldn't it be nice if it were that easy? Just whip up a few extra lenses in the microwave? We are fortunate that good quality lenses are available at decent prices.

I hear you! I can easily spend an hour working at keeping away every little speck of dust and dirt. I buy those cotton sticks in bulk!

This just goes to show how important it is to ALWAYS wear goggles. Just think of the hours of worry you have spent, not to mention the cost of the medical visit, even if you (hopefully) turn out to be OK.

Awesome picture, and awesome description. Thanks for the detailed notes. I am still a beginner, and my experiments have not yet been successful. After reading your notes, I think I have been turning on the laser too soon.