Opening a Bag of Powder (image) National Institute of Standards and Technology (NIST) Share Print E-Mail Caption Particles can contaminate the outside of a plastic bag when it is opened. This is a still from a video shot with a technique called laser light sheet flow visualization and used talc as a safe powder substitute. Credit E. Sisco and M. Staymates/NIST Usage Restrictions None 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.