A lot of pixels have been spent discussing this study of grade inflation, brought to most people’s attention via this New York Times blog. The key graph is this one, showing the fraction of grades given in each letter category over the last fifty years: Lots of effort is being put into trying to explain […]
Category: Playing-With-Graphs
Roller Slide Physics Simulated
I really ought to be doing other things, but this roller slide business kept nagging at me, and I eventually realized I could mock up a crude simulation of the results. This led to the production of this graph: This looks pretty similar to the Tracker Video data from the previous post, which I’ll reproduce […]
Roller Slide Physics Explained
On Monday, I posted a short video and asked about the underlying physics. Here’s the clip again, showing SteelyKid and then me going down a slide made up of a whole bunch of rollers at a local playground: The notable thing about this is that SteelyKid takes a much, much longer time to get down […]
The Test(ing) of Time 2: Freezing Time
A month and a half ago, I reported on a simple experiment to measure the performance of a timer from the teaching labs. I started the timer running at a particualr time, and over the next couple of weeks checked in regularly with the Official US Time display at the NIST website, recording the delay […]
Playground Physics: Roller Slide Mystery
We took SteelyKid to the playground at one of the local elementary schools on Sunday morning. this one includes an odd sort of slide, made of dozens of rollers that are 1-2 inches in diameter (they’re all the same size– the range is just because I didn’t measure them carefully). They’re on really good bearings, […]
Great Moments in Deceptive Graphs
This morning, via Twitter, I ran across one of the most spectacular examples of deceptive data presentation that I’ve ever seen. The graph in question is reproduced in this blog post by Bryan Caplan, and comes from this econ paper about benefits of education. The plot looks like this: This is one panel clipped out […]
This Is All For Science
Today’s Links Dump came late because I was at the meeting of the APS’s Committee on Informing the Public. We apologize for the inconvenience, but I was too busy acquiring this critically important scientific data: What is that, you ask? It’s this:
The Test(ing) of Time: Measuring the Performance of a Stopwatch
As I’ve mentioned before, I’m schedule to teach a class on “A Brief History of Timekeeping” next winter term as part of the Scholars Research Seminar program. Even though I have a hundred other things to do, I continue to think about this a lot. One of the goals of the course is to introduce […]
How Many Books Is That?: Modeling Amazon Sales Rank
A few months ago– just before the paperback release of How to Teach Physics to Your Dog— Amazon started providing not only their Sales Rank data, but also sales data from Nielsen BookScan. Of course, the BookScan data is very limited, giving you only four weeks, and the Sales Rank data, while available over the […]
Wind Power Economics and the Ability to Focus
Kevin Drum re-posts a chart on wind power made by Stuart Staniford showing that the number of new wind power plants installed in 2010 was way lower than in 2009 or 2008: This is meant as a starting point for discussion about the big economic issues that might’ve caused this. One of the many, many […]