How to Use Tracker Video Analysis software

Every do often, we may be doing data analysis of events recorded by video.  This might be a ball thrown through the air, a video game, a cool YouTube video you find, or anything that has motion involved.  The goal is to get your data from the video.  We will have three main ways of doing this.

One way is a scaling exercise.  Quite literally, you can measure the sizes and distances on the computer monitor.  If you know the actual size of on object in the video (perhaps a person or meterstick), you can scale lengths of any other object in the video to get its size, or to measure the distance the object moves.  The other quantity we need is time.  This will require either timing the event on the video, which could include just reading the time stamp of the video or timing with a stopwatch if the video is running in real time.

The other two methods are very similar, and use software.  Logger Pro, which is the software we use to run our Vernier sensors, and Tracker, a free online program, can have any video on your hard drive imported for analysis.  It is really cool stuff, and below is a video that explains how to use Tracker to get data from a video where a ball is tossed in the air.  Watch and learn, and then you will have chances to do this with any video we use during the year (or better yet, on your own when you are curious about something you capture on video).

Keep in mind, you can upload video from a camcorder or your cell phone onto your computer.  What about if you want to analyze an existing YouTube video, or if you want to analyze an online video game?  You will need to make a screencast video and save it on your computer, and then import that video file (recommend MP4 video) into Tracker or Logger Pro.  The easiest way to make a screencast video is Screencast-o-matic.

Former Chem-Phys Student Featured in Wired, for Skybox Start-up

Dan Berkenstock, a former ETHS student who came through Chem-Phys, is now a VP at Skybox, a start-up technology company in Silicon Valley.  Skybox is getting good press in Wired magazine, which describes the mission of Skybox here.  Skybox is building a satellite network that will be able to take high resolution photos all around the Earth, and use the vast amount of data in those photos to companies, governments, and so on.  With only about a dozen satellites currently able to do this, Skybox is going to, perhaps, corner this market.  There could be enormous financial rewards waiting if successful, so time will tell.  But keep in mind Dan used to sit in your seats, so this shows one path for your young, creative minds!

A really cool demonstration of momentum and energy.  Try to understand this one!  Where can we get long bead chains like this?!?!?!  We must try this one in class.

TED: Freeman Hrabowski and his 4 Pillars of College Success

A talk from the President of University of Maryland, Baltimore.  He marched with Dr. Martin Luther King as a boy, and now works on getting minorities, the poor, and other underrepresented groups into science and math.

Video for an Explosive Use of Capacitors and Conservation of Momentum, Watermellon style!

Courtesy of Louis S.:

The video I chose actually represents two aspects of physics in this class.  The set-up of the watermelon explosion is simply a large bank of capacitors wired together in series with an extremely high voltage. When one of the capacitors is discharged, there is an enormous current that runs through the watermelon, causing it to explode. This shows the relationship between capacitance, voltage, and current.  The other portion of this class can be seen with the high speed camera showing the watermelon explode.  When the watermelon is initially at rest, its momentum is zero.  Then, once it explodes, all of the little pieces of watermelon-shrapnel must fly off such that the components of their motion must equal zero.

Congratulations to the Class of 2013!! You will be missed

Each year this is a bittersweet time for me.  I hate to see the senior class leave, but at the same time I am tremendously happy for and proud of the students.  You are about to enter a new phase of life, and also one of the great times in life.  You are all prepared for college on the academic side, and you will quickly learn and adapt to independence on the personal and social sides.  Enjoy the experience!

Here's to the Class of 2013!  A job very well done!!
- Doc V

Congrats on Surviving AP Season!!

AP exams are done today, so Congratulations!!!!! 

Samsung Short Essay Contest on How Technology Helps Us Learn

Samsung is sponsoring a short essay contest for high school students.  You can write and submit a 300-word essay: An essay up to 300 words on what you think about technology advancements and how it will change the way we learn in the future. Is it for the better?

This could be fun.  This is also only about a single page essay on any technology you wish to address.  Give it a try.  Five scholarships of $1000 will be given to those papers judged as being the best.  Just let me know if you have an interest, and the link above allows you to sign up for the contest. 

Possible Hints of Dark Matter

Check out current results from two experiments, that show first hints of evidence for dark matter.  This is a proposed explanation for the observed motions and structures of galaxies, which cannot be explained by the amount of observable matter astronomers measure.  It will be an exciting story to follow over the coming months and years, as more data is collected and analyzed and scrutinized by physicists.

Possible Discrepancy in the Size of a Proton - IF Real, New Physics???

New measurements of the size of a proton, using a new method of muon interactions with protons rather than electron interactions for protons, reveals a ~4% discrepancy in the proton radius between the two methods.  Physicists are trying to figure out if this is due to some mistake being made with the muon experiment, or possibly some misunderstanding of systematic uncertainties in the experiment, or other 'boring' explanations for the difference.  The story can be found here.

However, if this result and difference hold after all the investigations are completed and are statistically significant, then this could be an indication of new physics beyond the current Standard Model theory, which is the foundational theory in particle physics for the past five decades.  Time will tell as the current experiments, as well as new experiments being designed and run to check these results, are completed over the next 5-10 years.

This is a wonderful example of how science works.  Experimental results are published in peer-reviewed journals, and are scrutinized by the scientific community.  When a discrepancy comes up with well established and well tested ideas over long periods of time, one needs to seriously and open-mindedly look at all possible explanations for the discrepancy. Results must be reproducible by independent groups.  Possible new explanations must be considered and tested and debated.  It is a slow process, but the goal is to uncover the truths in Nature, if at all possible, based on physical evidence.  This makes for the excitement that scientists encounter in their research programs!