A quick STEM challenge with a zip line for exploring gravity, force and motion, friction, and slope! This activity is very easy to differentiate and can be used with a wide range of students, making it ideal for STEM days, clubs, or STEM Family Night.**Turn this into a holiday STEM challenge with the following modifications:Use mini skeletons, pumpkins, bats, or ghosts (figures, cubes, or erasers) for a Halloween STEM zip lineUse Santa, a gingerbread man, or a reindeer (figures, cubes, or eraser