Why do buildings fall in earthquakes? - Vicki V. May

Earthquakes have always been a terrifying phenomenon, and they’ve become more deadly as our cities have grown — with collapsing buildings posing one of the largest risks. But why do buildings collapse in an earthquake? And how can it be prevented? Vicki V. May explains the physics of why it is not the sturdiest buildings, but the smartest, that will remain standing.

 Lesson by Vicki V. May, animation by Pew36 Animation Studios.

How Do Airplanes Fly?

How do airplanes fly?

 

How do Planetary Flybys Work?

NASA uses fly bys or gravity assists all the time, but what's actually going on? For more, including some links to mission proposals that take advantage of fly bys, check out my latest post over on Vintage Space.

 Title image via NASA. Music "The Coup" by AudioQuattro from Music Loops. Cheers to Jonathon Smith and JPL for the video.

For more Vintage Space, add me on Facebook, Google+, and Twitter as @astVintageSpace. And subscribe to Vintage Space on Popular Science for regular blog updates.

Amy Shira Teitel

 

Why Isn't "Zero G" the Same as "Zero Gravity"?

This Quick Question explains the difference between gravity and g-force, and how you can experience zero-g in space even when it’s not zero gravity!

 

Brian Cox visits the world's biggest vacuum chamber

Human Universe: Episode 4 Preview - BBC Two

Programme website: http://www.bbc.co.uk/programmes/p0276q28

Brian Cox visits NASA’s Space Power Facility in Ohio to see what happens when a bowling ball and a feather are dropped together under the conditions of outer space.

The Physics of Space Battles

How scientifically accurate is your favorite sci-fi space battle?

 

The Physics of Weightless Flight ft Emily Calandrelli

Ever wanted to know how those vomit comet planes simulate weightlessness?

 

How Long Can You Balance a Pencil?

Equilibrium.

 

Straight Rod Passing Through Curved Hole

Exhibition from the Science Museum in Valencia, Spain.

The experiment:

 

...and simulation:

Mystery of Prince Rupert's Drop at 130,000 fps - Smarter Every Day 86

From Wikipedia:

 "Prince Rupert's Drops are glass objects created by dripping molten glass into cold water. The glass cools into a tadpole-shaped droplet with a long, thin tail. The water rapidly cools the molten glass on the outside of the drop, while the inner portion of the drop remains significantly hotter. When the glass on the inside eventually cools, it contracts inside the already-solid outer part. This contraction sets up very large compressive stresses on the surface, while the core of the drop is in a state of tensile stress. It is a kind of toughened glass.

 The very high residual stress within the drop gives rise to unusual qualities, such as the ability to withstand a blow from a hammer on the bulbous end without breaking, while the drop will disintegrate explosively if the tail end is even slightly damaged."

A Baffling Balloon Behavior - Smarter Every Day 113

Helium balloon in an accelerating car.

 

How do figure skaters exploit Newtonian physics when they spin?

Legendary MIT physics professor Walter Lewin describes some of the science that was in action during the Winter Olympics in Sochi. He explains how ice-skaters use their arms to moderate their moment of inertia, which in turn affects the angular velocity of their spins. The biomechanics is fairly straightforward, but Walter Lewin always manages to make his lessons engaging thanks to his trademark charisma.

 

The Dynamics of an Elevator Ride

We go for a short ride in the elevator and record the acceleration for display.

 

How fast are you moving right now? - Tucker Hiatt

View full lesson: http://ed.ted.com/lessons/how-fast-are-you-moving-right-now-tucker-hiatt

"How fast are you moving?" seems like an easy question, but it's actually quite complicated -- and perhaps best answered by another question: "Relative to what?" Even when you think you're standing still, the Earth is moving relative to the Sun, which is moving relative to the Milky Way, which is...you get the idea. Tucker Hiatt unravels the concepts of absolute and relative speed.

 Lesson by Tucker Hiatt, animation by Zedem Media.

 

Free falling in outer space - Matt J. Carlson

View full lesson: http://ed.ted.com/lessons/free-falling-in-outer-space-matt-j-carlson 

If you were to orbit the Earth, you'd experience the feeling of free fall, not unlike what your stomach feels before a big dive on a roller coaster. With a little help from Sir Isaac Newton, Matt J. Carlson explains the basic forces acting on an astronaut and why you probably shouldn't try this one at home.

 Lesson by Matt J. Carlson, animation by Josh Harris.

 

The Cubli: a cube that can jump up, balance, and 'walk'

The Cubli is a 15 × 15 × 15 cm cube that can jump up and balance on its corner. Reaction wheels mounted on three faces of the cube rotate at high angular velocities and then brake suddenly, causing the Cubli to jump up. Once the Cubli has almost reached the corner stand up position, controlled motor torques are applied to make it balance on its corner. In addition to balancing, the motor torques can also be used to achieve a controlled fall such that the Cubli can be commanded to fall in any arbitrary direction. Combining these three abilities -- jumping up, balancing, and controlled falling -- the Cubli is able to 'walk'.

 Lead Researchers: Gajamohan Mohanarajah and Raffaello D'Andrea This work was done at the Institute for Dynamic Systems and Control, ETH Zurich, Switzerland and was funded in part by the Swiss National Science Foundation (SNSF), grant number 146717.

 For more details visit: http://www.idsc.ethz.ch/Research_DAndrea/Cubli

 

Moving Sand Cart Over a Rotating Surface

A sand-carrying cart on a track leaves a trail of sand when it travels over a rotating table. This demonstrates the Coriolis Effect.

 

Interrupted Pendulum

A pendulum swings from a support post and another post is added to interrupt its swing. We desire to know the maximum height at which the pendulum will perform a full loop around the post. The pendulum requires both potential and kinetic energy in order to complete a full loop. Therefore, it will never be able to return to its height of release while completing a full loop. Ultimately, the pendulum has enough energy to complete a full loop when interrupted at a height equal to two-fifths its initial height of release.

 

Science of Water Balloons from @sixtysymbols

What do physicists do with a high-speed camera, water balloons and a spare half hour!?

 

Hero's Engine

This demonstration illustrates the earliest form of steam engine, as described by Hero of Alexandria around 150 B.C. A small amount of water is heated to produce steam, which accelerates out of small tubes. In turn, the steam creates thrust and the engine quickly spins up.