Middle School Scientists at Work (image) University of Arizona Caption Students at Miles Exploratory Learning Center in Tucson, Ariz. place a leaf on a precision scale encased in a transparent box to ensure not even air movements interfere with the measurement. Credit Ben Blonder Usage Restrictions This visual may only be used in conjunction with reporting/posting of this news release. Image/video credit must be included exactly as indicated. Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.