Tuesday, November 15, 2011
The energy behind the car is the elastic potential energy in the rubber band. When it is pulled back the energy increases and when released the energy is transferred from the rubber band to the car.This force is equal and oppose of the pull which is Newton's 3rd law.The car also demonstration Newton's 1st law. Because when the unbalanced force, the rubber band acts on it it moves. It would continue to do that but because of friction and Newton's 1st law it slows to a stop when all the kinetic energy turns back into potential energy.
After testing my design and seeing other design be tested I would say that my design was fairly successful. The sling shot with the fishing line attached to it went 7 tiles. This so far seems to be faring well against the other competition but it will not be placing in the top two positions. Altering the design to make it within the rules was not my plan but it did not deter its performance. The uncoiling of the line seemed to slow it down a bit but it did do the required distance. If I were to do it again I would do two things differently. I would first have supported the wheels more properly so that it would not have gone on an angled track which deducted from its total amount of tiles traveled. Secondly, I would have read the rules more carefully so that no last minute changes would have had to be done and also so that I could have planned out the way to attached the fishing line car so to not have it catch on the wheels multiple times and so that the line would not have kept getting tangled. The reasons for errors were based in three main points. The first was the way the sponges were glued together made it easy for them to deform under the pressure of the rubber band. The second is reason was the way that the shoot was balanced. When the rubber band was pulled back and the sides angled inwards it had to be set exactly right or it would go off spinning because the sides were a bit of a different length. The last reason for error was the last minute changes that had to be done. By not reading the directions over after designing my design I had to find a loophole quickly and it was not fully thought out. The fishing line was the source of error in this situation. To further investigate the challenge, I would test other models such as the balloon power design or the mouse trap design. I could also reevaluate my design and perfect the fishing line design.
On Monday Mr. V came to me with concerns about my project. It turns out that having the car leave the sling shot and the sling shot not being part of the car is against the rules. At this I found a loophole! I attached a fishing line to the back of the car and the back wall of the shoot to go around that! PROBLEM SOLVED!!
Saturday, November 12, 2011
Hypothesis: If a modified sling shot made of a shoot and rubber bands,then a car is placed in between the rubber band’s arch and the rubber bands are released then the car will go forward.
Procedures: (after car and shoot are made)
- Pull back the rubber bands and hold
- Place car in the middle of the arch made by the rubber bands
- Insert the rubber bands into the notch in the back in the car while holding car in place
- Release the rubber bands by releasing the car.
After 10 test:
8 went straight and traveled over 5 tiles( 160 cm)
1 spun out of control and when about 100cm
1has the rubber bands catch on the wheels and did a 360 in the air
The experiment was successful. After testing the sling shot idea turned out to be the best design so I added to the design to make it work was proficiently as possible. Although a few tests did not show the results needed for full credit, this design is the most promising. The idea of a sling shot design is defiantly what the final design will be bases on.
Hypothesis: If I place a light cup on a newspaper with an edge and then pull back quickly, then the cup will roll forward
- Gather a light cylinder shaped cup and a sheet of newspaper
- Fold the edge of the newspaper over to create about an inch lip
- Place the newspaper a flat surface with the edge side down
- Place the cup on top of the newspaper
- Put the newspaper back as fast as possible without curving the paper or making the paper a ramp
When following the procedures little change in the cups position occurred.
When using a light cup and a edged piece of newspaper I was unable to move the cup enough to go a foot let alone 5 tiles. I suspect that the forces at work are not strong enough to overcome inertia or keep the cup spinning and without making a put upwards when the cup is rolling because of the slope created, it is not possible to move even a very light cup far with a newspaper .