You can guess.

What you will need To do this exercise, you will need the following tools - Something you can drop from a height (like a tennis ball - 3 balls is easy) - A fast timekeeping device like a stopwatch (built into many smartphones and watches) - String long enough to extend the distance to drop things - A yardstick, measuring tape, or something to measure the length of the string - Weights (e.g., metal washers) to tie onto the string - Markers to mark the string

Section 2: Exploration Experiment

The second half of this lab is for you to do your own mini-research project. I'd like you to use the tools we've worked with in this lab to try answering your own research question. Below are a few examples of the types of question you might ask. Select one of these or create your own. Remember that you need to do this experiment, not just discuss what you expect to find.

• How does changing the shape, size, or weight of the falling body change the results of this experiment? (You don't have to do all of these - select one or two variables that you will actually be able to test)
• Can you use other equipment of your own or in the lab to improve the accuracy of the falling body measurements?
• Return to one of the previous labs we've done and add uncertainty estimates to the exploration question results you gave.
• If you have experience with statistics, calculate the "1 sigma" and "3 sigma" uncertainties in the tavg² values for the class and use this to estimate the uncertainty in the measurement of g.
• Other questions you have related to the falling bodies or the process of measurement.

Note that the exploration experiment is a full experiment. Once you have selected one of these questions to work on you will need to collect data, make measurements, and analyze the results. In your writeup you will also have to describe the question (don't just copy the text above: say specifically which part you are working on), give a hypothesis of what you expect and why (what is the underlying cause of what you are seeing), describe in detail the steps you took to answer the question, list all of the data you used and any analysis you did, and finally, describe the conclusions you drew from the experiment. Note that you won't be marked down if your hypothesis turns out to be incorrect.

What You Turn In

You are welcome to work in small groups on this lab each student should have their own writeup. Turn in your answers to questions 1-7 along with Table I and the graph of the data.

You should also type up your discussion in your own words of Section 2: Exploration Experiment. In this discussion you should clearly describe the following:

• What the question is.
• What your hypothesis is.
• What procedure you used to answer the question.
• What data you took. (And any calculations you made)
• The conclusions you derived from this data.

The final writeup should be a few paragraphs long at least, and it should give enough detail that an interested reader can follow the steps you took and clearly see how you reached your conclusions.

Upload the typed discussion to the Lab folder on Canvas along with any tables, graphs, etc.