# Introduction to the Lab

Brokk Toggerson

Welcome to this first in the series of four labs where you will be looking at measuring the gravitational field . Now, the ideas of electric field in magnetic field are going to play really important roles in this class. However, these fields are a little more abstract and they are difficult to measure with just the everyday tools with which you’re very well familiar. So, we’re going to instead use the gravitational field to a help us enhance our understanding of this from Physics 1 and, at the same time, help us get a feel for how fields and forces are all connected.

For this first lab, you’re going to be measuring the gravitational field by dropping an object, such as a ball, and timing how long it takes to fall. You will drop it several times and from there be able to measure the gravitational field. Along the way, you’ll explore such concepts such as:

• how to write a procedure for even something really simple. Once again we’re keeping the experiments intentionally very simple so that you can really think about everything that’s going on.
• You will also explore how to take data that’s not a line and converted into a line which is a very useful thing to be able to do. You see it in all the literature and the reason for this is because lines are really easy for our little monkey brains to understand.
• You’ll explore how to determine if you’ve collected enough data.
• How to fit data to align and make a high quality plot ready for publication using a sophisticated tool called plotly.

That will be this lab. The next lab will be the same experiment: you’ll once again be measuring the gravitational field by timing how long it takes an object to fall. Why are we doing the same experiment twice? So that you can take your result and procedure from this experiment and think about it critically in such a way as to improve it. In the next lab, you will also apply more advanced analysis techniques, such as including uncertainties into your fit. The goal is to get a better result.

In the 3rd and 4th labs in the sequence, you’ll once again be measuring the gravitational field, but this time you’ll be doing it in an independent way: you’ll be using a pendulum. Ultimately, you’ll have two independent results for the measurement of the gravitational field and you’ll be able to compare them and see if the two results are consistent with one another or not. That’s the basic outline of this lab. As always, you will be using material from the prior lab in this one so you will use a Monte Carlo error propagation at some point. Let’s get on with the lab!