Category Archives: Physics

Tesla’s Powerwall: Reading the Meter

Image of Tesla Powerwall battery.
Photo by Tesla Energy.

April 2015 saw Tesla Motors’ entry into the home and industrial battery market. Thousands of pre-orders – and more than a little hype – attended the announcement, and it’s easy to see why: The promise of a cost-effective home battery, one that could make self-storage an equal or better option for solar customers than the prevailing sell-and-buyback model, could revolutionize the solar industry.

Yet some experts argue that the battery is not all it’s cracked up to be, while harsher critics accuse Tesla of using the storage cells as big green stalking horses, part of a plan to bilk taxpayers into subsidizing the company’s massive battery factory and R&D facility in Nevada. Read on as I make the connections in …

How the Tesla Powerwall Works

Coming to Grips with the Impalement Arts

A woman fastened to a spinning wheel has knives thrown at her.
The Wheel of Death: It’s a living. Photo by Ellin Beltz.

No one can say when people first started throwing knives, but I’m willing to bet that it was the result of boredom, desperation or an ill-thought-out dare.  How we got from there to the Wheel of Death involves a journey from Africa, through the Wild West shows and circuses of the 1800s, and finally to our own  backyards.

Knives hardly sail through the air like arrows, but throwing them is not a difficult as it might seem. So grab your weapon of choice and join me as I explain …

How Knife Throwing Works

Yellowstone and the Terrible, Horrible, No Good, Very Bad Day

False-color image of Lake Toba, the flooded 19-by-62 mile caldera of a supervolcano that may have jump-started a 10,000-year ice age.
False-color image of Lake Toba, the flooded 19-by-62 mile caldera of a supervolcano that may have jump-started a 10,000-year ice age.

The eruption of Krakatau in 1883 is synonymous with cataclysm, and with good reason. Its eruptive power equated to several thousand atom bombs, and it killed around 36,000 people. But compared to the supervolcanoes that nearly wiped out humanity, or that may yet spell global catastrophe, it was a wet squib.

Find out about the magma doom machine buried under America’s oldest national park as I take you on a tour of …

How Supervolcanoes Work

Ramjets: Making Mock of Mach

1946 ramjet test. Image courtesy NASA.

The faster you go, the less inclined the air becomes to get out of your way. This simple fact, which stood for years as an impediment to breaking the sound barrier, can also be ingeniously harnessed to create an engine capable of zipping along at supersonic speeds without the fuel weight required by rockets.

In this article, I trace the history, science and engineering behind this revolutionary “flying stovepipe,” from its theoretical birth during the biplane era to its modern military and commercial offshoots. By the time we’re done, you’ll understand…

How Ramjets Work

The James Webb Space Telescope Prepares to Peer Past Hubble

Artist's rendering of JWST
Artist’s rendering. Image courtesy NASA.

For two decades, the Earth-orbiting Hubble Space Telescope helped pierce the veil of time, image stellar nurseries and prove that galaxies collide. Now, the James Webb Space Telescope stands poised to take those observations to the next level, making the delicate observations possible only in the cold, dark spaces beyond the moon.

Slated for a 2018 launch date and team-built by 14 countries, 27 states and the District of Columbia, Webb will take astronomers closer to the beginning of time than ever before, granting glimpses of sights long hypothesized but never seen, from the birth of galaxies to light from the very first stars. Join us as we explore…

How the James Webb Space Telescope Will Work