Particle Sorting (IMAGE) University of Pennsylvania Caption In a computer simulation, the Penn team found that large particles rise to the top in a mixture. The size segregation took place in two stages, the first rapid, sorting the upper layers and the second slower, as large particles from the deep 'creeping' layer were swept upwards. Credit University of Pennsylvania Usage Restrictions In context of reporting License Licensed content 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.