OK this lab came out way better than I anticipated! The results were pretty consistent, minus a group or so from each class… Here is what we got.
1. The longer the tube, the further the marshmallow travels.
2. The harder you blow, the further the marshmallow travels.
3. The higher the mass of the marshmallow, the less far it travels.
4. The higher the marshmallow is shot from, the further it travels.
The first three were BRILLIANT in explaining J = delta p. First we WB the results and did a gallery walk, where they checked all results to see how they compared as a class. We talked first and developed the equation Ft = delta (mv) as we went….
We discussed variable by variable what we got and WHY. They intuitively could see that if you blow harder, the mallow should go faster as it leaves the tube (and therefore farther). The “F” part of the equation increasing, therefore increasing the “v” part (all else was held constant).
When the tube is longer, they said it was in there getting the force for longer… so the “t” part of the equation increasing, thus again increasing the “v” part. (all else held constant)
When the mallow was more massive, it did not go as far. Again, they sort of intuitively know this even though we have not done F = ma yet. Same blow force and same tube length means the Ft part of equation is same in all trials. So when the “m” is bigger, the “v” is smaller, meaning the mallow does not go as far. Brilliant.
Lastly, changing the height did not affect anything in the tube, same F, t and m will make for same “v” each trial…. but yet the mallow goes farther when starting higher. No study of projectiles, but through some drawings they could see that the time to fall is more, so the mallow has more time to move before hitting the ground, getting further.
The reports I have glanced at look really great. I am really proud of them! A great experiment for learning the concepts as well as designing an experiment (esp. in controlling variables!). LOVE THIS!!!