PhET Collision Lab: Introduction in One Dimension Homework assignment which may be done with a partner Learning goals: ⋅ Draw 'before-and-after' pictures of collisions. Construct appropriate vector representations of 'before-and-after' collisions. Explain what variables are conserved and under what conditions. What does elasticity mean? Identify vector and scalar quantities. Directions: 1. Experiment with one-dimension elastic collisions (Check Id and set elasticity at 100).