MIT is  Mare Island Technology Academy (

First:  For the Monday linear equation activity, I want them (working in groups, and one smartphone per group) to take smartphone pictures of  jet contrails from Travis AFB or elsewhere, with a good  measurement of time. This should be easy for them. Then, they put the images into Salsa J and analyze them.  We get Pixels per second motion.

Now!  Here is a possible method to try to figure out how to get meters per second (actually, this may be for more experienced students, and it may not work) If we have two students take two pictures at exactly the same time, and the  students are separated by about twenty meters, I think we should get a noticeable parallax, like we see in astronomy (I am checking my arithmetic on this one!).  Two students separated by 20 meters, measuring an airplane from Travis at 20 kilometers would give a differential angular displacement (I am not sure where our distant reference stars are) of 1/1000 of a radian, which is about 2 to 4 pixels of difference of location of the airplane in the smartphone image, I estimate. Again, this depends on finding a distant object to measure against. Sweet, ehh?  It might be a good app for someone to write -- "using two smart phones (or just one if the target is not moving) to measure distances. Pretty cool, ehh?