Measuring the Toughness of the Material Chocolate (1 of 2) (image) University of Sheffield Share Print E-Mail Caption Measuring the toughness of the material chocolate. Credit The University of Sheffield Usage Restrictions Only use to accompany this article, and the University must be credited. Share Print E-Mail 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.