1) The document is a worksheet on elasticity and Hooke's law for high school students. It contains introduction to concepts of elasticity, procedures for virtual lab experiments on springs using PhET simulations, tables to record data and questions for analysis.
2) The experiments measure the change in length of springs under different masses to study the relationship between force and extension. Students are required to plot graphs and determine spring constants from the data.
3) The worksheet aims to help students understand the concept of elasticity, conduct virtual experiments on springs, analyze results and conclude on the elastic properties of different springs based on their constants.