Thursday, January 21, 2016

Exploring G-Force with Physics Toolbox

In this activity, we will use the G-force detection capabilities of a standard smartphone. The accelerometer in a phone uses a small silicon chip and detects, using capacitors, the motion of this chip relative to the housing of the phone. This allows the phone to know what orientation the phone is in relative to the surface of the Earth, and change the orientation of the phone's display accordingly. It also allows some fun with physics!

A free app called Physics Toolbox by Vieyra Software takes data from the phone's accelerometer and graphs it over time. With this data made available using the average smartphone, a wide range of exploration and experimentation are now possible with a device that most students habitually carry around in their pocket.

For this activity, we'll use the Physics Toolbox interface to have some fun with orientation and movement in space.

1. In the reference frame of the phone, which direction corresponds to which Cartesian component? For example, does the top of the phone point in the positive or negative x, y, or z-component? Does this change if the phone is rotated?

2. Can you make your graph look something like this picture? (Include only the green and blue line in the Physics Toolbox display)

  1. Can you keep the total g-force (white line) above 1 for longer than a few seconds?

Here are some labs where the primary data collection and recording are done using Physics Toolbox, made available on

“Identifying Gait Metrics”
"Exploring Three-Component Seismic Data with Accelerometers"
"How Hard Does the Ground Shake During an Earthquake?"
“Measuring height in an Elevator ride”

And lots more!


Physics Apps

A non-exhaustive list of mobile apps that enable smartphones and tablets to become scientific instruments.

Vernier Video Physics
"Video Physics brings automated object tracking and video analysis to iPhone, iPod touch, and iPad. Capture video of an object in motion, then tap to track the object automatically. Video Physics instantly creates trajectory, position, and velocity graphs for the object."

Physics Toolbox
"Useful for education, academia, and industry, this app uses device sensor inputs to collect, record, and export data. in comma separated value (csv) format through a .txt file sent via an e-mail or through Google Drive. All analog data is plotted against elapsed time (or clock time) on a graph. Users can export the data for further analysis in a spreadsheet or plotting tool. The app also allows for a tone generator output. A menu allows the user to swap out sensor data collection between the following data sensors:

(1) G-Force Meter - ratio of Fn/Fg
(2) Linear Accelerometer - acceleration
(3) Gyroscope - radial velocity
(4) Barometer - atmospheric pressure
(5) Roller Coaster - G-Force Meter, Linear Accelerometer, Gyroscope, and Barometer
(6) Proximeter - periodic motion and timer
(7) Hygrometer - relative humidity
(8) Thermometer - temperature
(9) Magnetometer - magnetic field intensity
(10) Light Meter - light intensity
(11) Sound Meter - sound intensity
(12) Tone Generator - frequency producer
(13) Orientation - azimuth, roll, pitch
(14) Stroboscope"

"-Measure and display sensor data in real time
-Display data in a graph, bar graph, analog meter, digits or table
-Build custom displays--mix display types, images, videos, text and assessments
-Analyze data with built-in statistical tools (min, max, mean, standard deviation, count and area)
-Select from 6 different curve fits including linear and quadratic
-Pinch and zoom manipulation of graphs
-Capture and annotate images
-Add videos, photos and GIFs
-Open and perform any of the 60+ SPARKlab interactive lab activities available free online
-Create and export electronic student lab journals
-Integrated with cloud-based file sharing services such as Dropbox and more
-Add assessments including multiple choice, drop down lists, and free text response
-Live data sharing and session sharing across devices--with each student capturing the shared data on their own device for further analysis"

"AccelGraph displays you the acceleration applied to your iPhone or iPod Touch with the help of its built in motion sensor graphically. 
• High-Pass filtering (optional)
• Seperate X,Y and Z-Axis graphs
• 3 different sampling frequencies
• Pause/Resume acceleration measuring
• Turn On/Off acceleration measurment on each axis individually
• Record acceleration on all axes
• Four different recording frequencies
• Acceleration measurement automatically saved
• Email acceleration measurement
• G-Force-Meters menu
• G-Force meters for all axes
• Four different backgrounds to chose from"

Audio Kit
"Audio Kit is a collection of four tools which are essential for those working in audio, sound and music. A real time Spectrum Analyser, a Scope to display waveforms, an SPL (Sound Pressure Level) Meter, and a Signal Generator producing sine waves, white noise and pink noise."

"Digital dual-trace storage oscilloscope
- Advanced autocorrelation triggering
- 1 or 2 traces
- Microphone input
- Adjustable gain and frequency"

Audacity is a free, open source, cross-platform software for recording and editing sounds.

Acoustic Ruler Pro
"Wouldn't it be amazing to have a ruler in your pocket all the time? Well now you can! Measure distances of up to 25 meters (82 feet) with two devices or up to 1.10 meters with one device and headphones.

The app works by clocking the time delay of the emitted sound waves. There are two different operation modes: a single device operation (with headphones) and a dual device mode for measuring the distance *between* two devices." 

"AndroSensor is the absolute all-in-one diagnostic tool that lets you know virtually everything about your device's status.
AndroSensor supports all the sensors an android device can have and it will tell you which of them are not supported by your hardware.
View in a single screen the data from all device's sensors in real time. Graphical and text output available for each sensor (graphs are not available for proximity, location and battery info).
- location, location provider, accuracy, altitude, speed and GPS NMEA data.
- Google maps to show the above info. Tapping on your location shows your address, postal code and location accuracy (if available)
- accelerometer readings, (incl. linear acceleration and gravity sensors)
- gyroscope readings,
- light sensor value,
- ambient magnetic field values,
- device orientation
- proximity sensor readings
- pressure sensor (barometer)
- relative humidity sensor
- temperature readings
- battery status, voltage, temperature and health
- sound level meter (decibel)
- If your device supports it, next to the sensor's name, you will see how much power the sensor consumes per hour in mA.
AndroSensor also allows you to record everything from your sensors into a CSV file."

"This is a real working radioactivity counter. You only need a BLACK TAPE to cover the lense...
The App is using the camera sensor to detect radiation, like a geiger mueller counter, of course with a smaller area. We tested several mobile phones at the Helmholtz research facility in Munich, using a professional radiation device in the range of 2-10 µGy/h till 1-10 Gy/h (CS137 and CO60). The CMOS sensors can detect primary gamma radiation and some higher beta radiation (depends on the shieldings in the mobile phone). Typically not going into saturation as most GM tubes"

Wednesday, January 20, 2016

Physics Labs and Activities

What follows is a list of papers outlining Physics labs and activities that are possible using mobile devices as primary data collection tools with the appropriate app installed. The app listed under the paper is the one mentioned by the paper's authors, but many other apps might enable the same functionality. A list of apps is compiled in another blog post. 

Jochen Kuhn from Kaiserlautern University of Technology and Patrik Vogt from the University of Education Freiburg have paved the way with their blog, iPhysicsLabs in The Physics Teacher. They have written many of these papers and their contribution to the world of Smartphone Physics is appreciated.
Using iPads to illustrate the impulse-momentum relationship
Jefferson W. Streepey
Phys. Teach. 51, 54 (2013);
    Students use the accelerometer in an iPad to see that it is not the peak value of acceleration, but the size of the impulse that affects movement. App used: SparkVUE

Jochen Kuhn and Patrik Vogt
Phys. Teach. 51, 118 (2013);
    Capturing sound using the device’s microphone, and using Fourier analysis to illustrate the difference between sound, noise, and tone. App used: Audio Kit

Patrik Vogt and Jochen Kuhn
Phys. Teach. 51, 182 (2013);
    Using a device’s accelerometer, the radial acceleration of a merry-go-round is measured and analyzed. In the lab, the relationship between radial acceleration, radius, and tangential velocity can be explored. App used: SPARKvue or Accelogger

Patrik Gabriel and Udo Backhaus
Phys. Teach. 51, 246 (2013);
    In combination with a phone’s built-in GPS receiver and Google Earth, especially the elevation profiles provided by the latter, kinematics values can be taken for motion over long distances. An example is given of a longboarding descent, comparing speed changes to elevation changes. Apps used: Google Earth, built-in GPS apps

Oliver Schwarz, Patrik Vogt and Jochen Kuhn
Phys. Teach. 51, 312 (2013);
    The audio of a ball bouncing is recorded. The change in energy of the noise for each successive bounce is used to infer the coefficient of restitution of the ball. Using this, and the time between bounces, it is possible to obtain acceleration due to gravity. Apps used: Oscilloscope, or alternatively, Audacity

Lars-Jochen Thoms, Giuseppe Colicchia and Raimund Girwidz
Phys. Teach. 51, 440 (2013);
Diffraction lenses are used to view colours produced on a smartphone, to see how the LCD display used primary colour addition to make colourful images. App used: Any graphical software

Sara Orsola Parolin and Giovanni Pezzi
Phys. Teach. 51, 508 (2013);
Using two smartphones, the time between acoustic signal sent and received is used to determine the speed of sound in several different gases. App used: Acoustic Ruler Pro

Asif Shakur and Taylor Sinatra
Phys. Teach. 51, 564 (2013);
    The gyroscope in a smartphone records data as the phone spins along with a rotating platform. A weight is dropped on the platform and the data is analyzed with reference to angular momentum and rotational kinetic energy. App used: xSensor

Jochen Kuhn, Patrik Vogt and Andreas Müller
Phys. Teach. 52, 55 (2014);
The side-to-side motion of an elevator is recorded and compared to the estimated length of the elevator cable, modeling the elevator as a pendulum. App used: SPARKvue or Accelogger

Patrik Vogt and Jochen Kuhn
Phys. Teach. 52, 118 (2014);
Elastic, inelastic, and partly inelastic collisions are investigated using smartphones in place of typical accelerometer. App used: SPARKvue or Accelogger

Martín Monteiro, Cecilia Cabeza and Arturo C. Marti
Phys. Teach. 52, 180 (2014);
Using a gyroscope, the rotation of a bicycle wheel is characterized. Rotational energy and angular momentum are considered. App used: AndroSensor

Jochen Kuhn, Patrik Vogt and Michael Hirth
Phys. Teach. 52, 248 (2014);
The beat phenomenon is explored by producing two tones of slightly different frequencies using smartphone speakers and recorded using a smartphone microphone. App used: Oscilloscope and Audio Kit

Martín Monteiro, Cecilia Cabeza, Arturo C. Marti, Patrik Vogt and Jochen Kuhn
Phys. Teach. 52, 312 (2014);
   A smartphone is mounted to a merry-go-round, and radial acceleration is recorded during rotational motion. The relationship between acceleration and angular velocity is explored, and kinematics equations are verified. App used: Unspecified

Nadji, Taoufik
Phys. Teach. 50, 307 (2012);     10.1119/1.3703551
    The instructor drops an iPad from the top of a stairwell, and students catch it two flights below using a blanket. The concept of zero acceleration is explored, with attention given to reference frames. App used: AccelGraph

Richard P. Hechter;
Phys. Teach. 51, 346 (2013); 10.1119/1.4818370
Students stage and film the shooting of a hockey puck. It is modeled as a projectile and LoggerPro video analysis is performed. App used: LoggerPro
Sándor Egri and Lóránt Szabó
Phys. Teach. 53, 162 (2015);
    A cart is attached to springs on either side and allowed to oscillate as governed by Hooke’s law. A smartphone is fixed to the cart and records the acceleration data. App used: a program developed by the authors. However, any accelerometer app will work

Marcus Meißner and Hendrik Haertig
Phys. Teach. 52, 440 (2014);
    The International Space Station can be filmed using the camera in a smartphone. Based on how long the ISS is in view, its orbital speed can be calculated. It is also possible to estimate the height of the ISS above the surface of the Earth. App used: Built in camera

Jochen Kuhn, Alexander Molz, Sebastian Gröber and Jan Frübis
Phys. Teach. 52, 351 (2014);
    Three distinct investigations relating to light are explained: the inverse-square law of power, absorption, and decay. App used: RadioactivityCounter

Martín Monteiro, Patrik Vogt, Cecilia Stari, Cecilia Cabeza, Arturo C. Marti
     A smartphone is mounted to a drone and flown upwards several hundred feet, recording atmospheric data on the way. Combined with data taken from commercial cruising altitude, this is compared to atmospheric models. App used: AndroSensor

Exploring G-force with Physics Toolbox
Of my design, this activity is a quick introduction to get students used to the accelerometer app and  the reference frame of the phone.