These two investigations (GOOGLE and PDF versions) allow students to develop an understanding of the relationship between kinetic energy and mass of an object, and kinetic energy and speed of an object. As students are collecting their own data, it is more understandable compared to being given data to analyze. This activity supports the NGSS standard MS PS3-1A review (or introduction) of some of the key terms such as mass, kinetic energy, speed, energy transformations, and conservation of energ