Tim Bell stands in front of a crowd of squirming elementary students. He sticks five candles into a cake, lights three and declares it fit for a 21st birthday. Even an audience that can barely spell the word "computer" knows that 21 candles belong on the cake. But Bell, an associate professor of computer science and software engineering at the University of Canterbury in New Zealand, is not talking about simple arithmetic. On this particular Saturday morning, he is at Butler University to explain binary code and other scientific computer concepts to kids during a one-hour presentation.

There were hundreds of gawkers and exhibits from all over the world. But nothing made the Intel Science and Engineering Fair last month feel more like a zoo than the signs: "Please do not poke, tease, or feed the science nerds."

Should you destroy a life to save a life? That question is facing many scientists in the lab today. Youths are also talking about this issue. At School 91, 5111 Evanston Ave., middle-school students presented reports on the pros and cons of embryonic stem cell research. Embryonic stem cells are highly prized by researchers because they have the potential to develop into cells for almost any organ

"Everything that can be invented has been invented." This statement has been attributed (probably falsely) to Charles H. Duell, commissioner of the U.S. Patent Office in 1899. Duell believed in innovation, as do thousands of U.S. students who participate in science fairs, hoping to discover something new. Although science fairs rarely seem to venture into unknown territory, they still can inspire

A high school girl's science project has alerted many people to the potential hazards of heating food in microwave ovens. When Claire Nelson was 12 and growing up in Little Rock, Ark., she struggled to come up with a science fair project. As she and her mother discussed some articles she was reading for her science class, the topic turned to diethylhexyl adipate, or DEHA, a carcinogen found in pla