This lab's purpose is for students to get a better first hand understanding of how weight and mass are different but yet linked to each other. For my students, following this lab and their work with this concept of weight being different from mass they are no longer allowed to use weight in replace of mass in their responses either verbal or written. On assessments the use of the terms incorrectly means deductions in credit.
You will need access to a box of flat metal washers (enough for each team to have at least 9. I have teams next to each other share washers with one team starting at 15 washers and the other at 3 so the group starting with 15 can share their extra with the team starting with 3. These can be purchased at your local hardware store. They should be fairly large. You will also need spring scales which measure in newtons (at least one per team/group and some large paperclips (one per spring scale)) and regular mass scales. The paperclip should be un-bent so it looks like a christmas tree ornament hook. This will allow the students to add more washers than the hook on the end of the spring scale will hold.
The students add washers to the spring scale and record the weight (gravitational force) in Newtons the scale reads. They also measure the mass of the washer(s) each time. This will allow them to compare how weight changes with mass and they are not the same even though they are related.
Be sure to discuss how weight is due to the FORCE of gravity and does not exist without gravity while mass is a property all matter has no matter what. You still have mass in space but not weight while your mass remains the same on other planets your weight varies....this leads to part 2 of the lab.
Part 2 students calculate the weight of each amount of washers based on the acceleration of gravity on each planet. They then need to create a triple line graph (one line per planet) of the mass vs weight on each planet. Depending on your student ability to graph they made need help or you can cut that part without losing the purpose of the lab.
Following these there are 16 analysis questions for students to work on.