12-Sept-2016: Free Fall Lab

Purpose: For this lab, we will try to determine the value of gravity using an apparatus the measures the free fall of the body held by an electromagnet and then released, marking on a piece of tape as the body falls. We will eventually compare our results with the rest of the groups in order to determine errors and uncertainty (Part 2).

Procedure: Using the pre-marked tape from the free fall of the object (thanks to professor in order to save much time), my group measured the distance between markings, up to 12 marks. Shown in the picture is a quick, rough sketch of the measured distances between the markings. (This data would eventually be put into an Excel spreadsheet).

After my group measured each mark, we made a spreadsheet in Excel with these numbers. Along with the time and distance, we created a ∆x (change in distance from each point) colum, and a Mid-inerval column for the time and speed. Of course, using these numbers (columns D and E) we created a graph, shown in the picture.

In addition, we also created a graph using columns A and B .

Part 2: In part 2, groups in the whole class compared their numbers. These numbers are listed in the picture. (I am group 4).

Using these numbers we found the mean value of the class. We also found the Standard Deviation of the Mean of the class' data.

Questions/Conclusions:

1. What pattern (if any) is there in the values of our values of g? The only pattern I noticed in the values of g is that they were ranging in the 900s (except for one).

2. How does our average compare with the accepted value of g? Our average of g is low compared to the accepted value.

3. What pattern (if any) is there in the class' value of g? The pattern I saw in the class' value of g was that they were very low (except for one group which got the exact accepted value of g).

4. What might account with any difference between the average value of your measurements and those of the class? Which of these are systematic errors? Which are random errors? One difference between the value of my measurements are systematic errors, which can be caused by mis-reading of the instrument by the handler or the instrument itself is not properly calibrated. Another is random, for example, can be caused by taking a measurement of the tape as it is slightly folded in one area and smooth in another area, causing a mis-reading in measurements.

5. Write a paragraph summarizing the point of this part of the lab. What were the key ideas? What were you supposed to get out of it? The point of this part of the lab, in my opinion, is to acknowledge that every experiment data, whether it is from individual or groups, will have a different uncertainty and a deviation from each other. I believe collecting data from a larger number experiments will improve in what we accept to be the accepted value.