# 7.2: Activities


## Things You Will Need

Nothing! Much of the data has been meticulously collected for you, though you do need to extract more from the video recordings below.

## The Data

In this lab, you will have the opportunity to see the action and collect data for yourself, followed by analyzing it to determine the strength of the Earth's magnetic field (in the region of the lab in which the data was taken). We'll start with some basic static measurements that apply to all of the runs:

• radius of the wire coils: $$r=15.7cm$$
• separation of magnet from coils, along the axis: $$z=4.0cm$$
• number of turns in each coil: $$N=100$$

Below are video recordings of oscillations of the magnets for 9 different amounts of current passing through the coils. All of the oscillations last for a duration of 30 seconds, and the videos are at half-speed for easier viewing.

1. Explain what data you are extracting from these videos, and how you are obtaining it.

## Data Analysis

1. Create a data table to organize the information you have for the 9 runs. It should include columns for raw numbers measured (such as the current through the coils), and columns for values calculated from those raw numbers (such as the magnetic field contributed by the loops) that you will need to create your linear plot.
2. Plot the data in a graph, and construct a best-fit line.
3. Use the best-fit line to determine the Earth's magnetic field in the laboratory where the experiment was performed. Compare this with the established range of 2.5 to 6.5 ($$\times 10^{-5}$$) Tesla. [We expect it to be on the lower end of this range, given our laboratory's distance from the Earth's magnetic poles.]

## Lab Report

Download, print, and complete this document, then upload your lab report to Canvas. [If you don't have a printer, then two other options are to edit the pdf directly on a computer, or create a facsimile of the lab report format by hand.]

This page titled 7.2: Activities is shared under a CC BY-SA 4.0 license and was authored, remixed, and/or curated by Tom Weideman directly on the LibreTexts platform.