Oftentimes students have difficulty making the connection between the motion of a mass on a spring and the motion of a pendulum. This virtual lab helps them to make the connection! It's actually two labs in one-the first part asks them to analyze the motion of a mass on a spring, then the second part asks them to analyze the motion of a pendulum. For the conclusion, students are then asked to look for similarities and differences between the two! This is a long lab that takes a significant amount of time-so I would suggest pairing students up to complete this lab. I've used this in an introductory algebra/trigonometry based university physics course, but it could easily be used with high school students as well.