Tumbling Toast Dynamics Experiment

1)

The materials that were used to conduct this experiment included whole wheat bread, Balance brand butter, table, meter stick, toaster, sand paper, foam, and plastic, butter knife, and paper towel.

2)

To evaluate the static coefficient of friction between the toast and the different platforms used, several trials were performed on each type of platform. Then the values were averaged together. The results were that the static coefficient of friction between the plastic surface and the toast was 0.38, between the sand paper and the toast was 1.6 and finally between the foam and the toast the friction was 0.67.

The dimension of the toast that was used to conduct this experiment was an “e” value of 0.005m (0.5cm) and a “b” value of 0.045m (4.5cm). As a result, the overall dimension of the toast was a length of 0.09m (9cm) and a thickness of 0.01m (1cm). The height “h” of this experiment changed throughout the experiment so the effects of the height could be captured. The three heights that were used were as followed 0.38m, 0.93m and 1.79m. See picture at the top of the next page to see a pictorial representation of the experiment and dimensions used.

3)

To preform this experiment use the following procedure:

1. Gather all materials required to preform this experiment. (Materials listed above in question II.1)
2.  With the meter stick measure and record the height from which you will be conducting this experiment.
3. Clear surface to make sure to reduce error in experiment. Also place paper towel where it is predicted toast will fall to avoid a mess.
4. Make any modifications to the slice of bread’s dimensions, which may be desired, otherwise measure and record the dimension of the slice of bread, which you will be using.
5. Set the slice of bread in the toaster and toast the bread to desired level of toasty-ness. (Make sure to keep this variable consistent throughout the experiment) 
6.   Carefully remove the slice of bread from the toaster, avoiding contact with any hot surfaces.
7. Lightly tap toast to remove any excess crumbs.
8. Grab the butter knife and the balanced brand butter and lightly spread some butter on one of the sides of the toast.
9. Place the toast at the edge of the table butter side up so that the flat bottom of the toast is perpendicular to the table. Please refer to the picture on the below. Make sure that enough of the toast is on the table that the toast will not slide down and fall by its self.

1. Carefully apply a small force on the tableside of the toast until the toast slips and falls. (Applying too much force will affect the results of this experiment)
2. Record how the toast fell and if it experimental data matches the theoretical data.
3. Repeat steps 9-11 for trials 2 and 3 of the experiment.
4.  Change the surface from which the toast is placed on and repeat the experiment.
5. After the three trials have been preformed on the three surfaces change the height of which this experiment is conducted and repeat steps 2-13.

4)

Please see table below for the results from the data collected:

After careful analysis of the data acquired we were able to conclude that the theoretical data and the experimental data do in fact correlate very nicely. There were only two instances that the theoretical data differed from the experimental data acquired. After this experiment we can conclude that this model is an acceptable representation of this project.

Some of the way that this model can be improved is by reducing the variability in the shape and size of the slice of bread.  One of the ways of doing this would be if you used something as similar to a cookie cutter. By cutting every single slice of bread the exact same you would be able to reduce the amount of error in this experiment. It would also be easer to take measurements of the slice of bread. Another possible improvement for this experiment is how the static coefficient of friction is calculated. It would be interesting to see if you would get similar values if instead you used a spring scale to capture this data. The normal force of a slice of bread would be very easy to calculate and by dividing the force required to start to move the bread you would be able to calculate the coefficient of friction between the two surfaces. The final possible improvement for this experiment is to take into account the radius on the edge from which the bread is falling off of. It would be interesting to see if a edge with a round or large radius would still produce the same results as if an edge with a very sharp radius or no radius was used.