7 Lab 2: Magnetic Fields
liyuchon
Acknowledgment
This project is made possible with funding by the Government of Ontario and through eCampusOntario’s support of the Virtual Learning Strategy. To learn more about the Virtual Learning Strategy visit: https://vls.ecampusontario.ca.
PHY137 Stay-At-home Experiment 2
Magnetic Fields
What you will do
Use the built-in magnetometer of your cell phone to explore the magnetic fields of the Earth, the neodymium magnet, and a solenoid.
What you will need
- A cell phone that has a built-in magnetometer
- The Phyphox app installed on the cell phone
- Copper wire (more than 1 foot in length)
- 1 AA battery
- 1 neodymium magnet
- A small non-metal object that is about 3~5 cm thick (such as an eraser, a pen cap, or the prism in the lab kit with the paper packaging on)
Demonstration Video: https://youtu.be/rElg7NlKAGo
Procedures
Part I – the magnetic field of the Earth
- Make sure your phone is at least 1 meter away from any wall, metal, or magnetic objects at home. Make sure you are not carrying any metal or magnetic items with you.
- Open the magnetometer sensor in the Phyphox app. (If this sensor is grayed out, it means your phone is not equipped with a magnetometer. Please contact us if it is your case.)
- Start a magnetometer measurement. Turn and tilt your phone until the Magnetometer y component reaches the maximum positive value. (When the y component reaches maximum, the x and z components should be close to zero.) (If the “accuracy” showing on the top of the screen is not “high”, you can calibrate the magnetometer by moving the phone along a figure “8”, as described here: https://calibratecompass.com/)
- Keep the phone stationary at the location and orientation of Step 3, stop the magnetometer measurement. Export the data as a csv file. (You may find it helpful to rest your hand on your body to reduce inadvertent hand motion.)
- Still keeping the phone stationary, quit to the main menu and start an inclination measurement. Stop the measurement in 3~5 seconds. Export the data as a csv (comma, decimal point) file.
- Repeat Steps 1-5 above for a total of 3 different locations. If you do not have enough space indoors, feel free to go outdoors.
- Briefly describe the surroundings of your 3 locations (how much empty space do you have, what are the main obstacles nearby. You may attach photos if you do not mind.) You may attach photos if you do not mind.
- In the data exported for each Magnetometer measurement, find the magnetic flux density (B-field) of the geomagnetic field. Attach the magnetic field vs. time curve, and indicate which segment was used for calculating the average value and the uncertainties.
- In the data exported for each inclination measurement, take the average inclination angle (‘Flat.csv’, column ‘tilt up/down’) during the entire measurement time as the inclination angle, and the standard deviation as the uncertainty in the average. (If the numbers are shown as #####, increase the width of