low battery

i found out yesterday why when you buy something with batteries they don't last long. as i was checking out at wal-mart last night there were two kids with what looked like their grandparents in line behind me. not unusual. they were about seven and eight. as i waited for my groceries to get bagged i looked back toward the two kids. the one kid had some kind of a laser he had picked up in the checkout lane. he was shining it in the other kid's eye. continually. apparently, he was trying to see how long he could stare at the blinding, retina burning, red laser light without blinking. so after what seemed to be a half an hour the kid finally blinks. and then it was the other kid's turn. and now you know.