In this video Paul Andersen explains how the dimensions of space and time are combined in relativistic mechanics. Gravity and velocity can affect both space and time according to Albert Einstein's Special Law of Relativity.

In this video Paul Andersen defines the equilibrium constant (K) and explains how it can be calculated in various reversible reactions. The equilibrium constant is a ratio of the concentration of the products to the concentration of the...

What do Euclid, 12-year-old Einstein, and American President James Garfield have in common? They all came up with elegant proofs for the famous Pythagorean theorem, one of the most fundamental rules of geometry and the basis for...

From something as miniscule as a cell to the biosphere we all call home, living things fit together in numerous interesting ways. Bobbi Seleski catalogs biology from our body and beyond, tracking how unicellular organisms, tissues,...

You may know it as a miracle powder or an ice cream flavor, but activated charcoal can do some pretty cool stuff.

In this video Paul Andersen explains how waves will diffract (or bend) around an obstacle or while traveling through and opening. Diffraction will be maximized when the size of the opening or obstacle matches the wavelength.

The idea that humans react to disasters by losing control and acting selfishly is all too prevalent, especially in movies and television. But recent studies on altruism may provide evidence that this isn’t always the case, and this...

Changing colors -- it’s not just for chameleons! Many species of octopuses, squid and cuttlefish can do it, as well as a few insects, and even mammals and birds. Find out what feats of biology different animals use to change their...

Here's a paradox you don't hear much about: despite a century of creating machines to do our work for us, the proportion of adults in the uS with a job has consistently gone up for the past 125 years. Why hasn't human labor become...

In 1816, Europe and North America were plagued by heavy rains, odd-colored snow, famines, strange fogs and very cold weather well into June. Though many people believed it to be the apocalypse, this "year without a summer" was actually...

Part of why we're so fascinated with extinct dinosaurs it's just hard for us to believe that animals that huge actually existed. And yet, they existed! From the Jurassic to the Cretaceous Periods, creatures as tall as a five-story...

As the Earth's surface temperature gradually rises, it has become vital for us to predict the rate of this increase with as much precision as possible. In order to do that, scientists need to understand more about aerosols and clouds....

Vik Muniz makes art from pretty much anything, be it shredded paper, wire, clouds or diamonds. Here he describes the thinking behind his work and takes us on a tour of his incredible images.

Megafires, individual fires that burn more than 100,000 acres, are on the rise in the western United States -- the direct result of unintentional yet massive changes we've brought to the forests through a century of misguided management....

Mr. Andersen surveys properties of matter. A brief discussion of Archimede's Principle, Charles Law, Boyle's Law, and viscosity is included.

This video describes some of the ways that living and nonliving things in ecosystems interact. Beautiful, colorful videos help illustrate these interactions in ecosystems such as deserts, grasslands, and wetlands. Specific emphasis is...

The Chandra X-ray Observatory has discovered a black hole growing at a record pace. Credit: NASA/CXC/A. Hobart

Get to know this large marine mammal.

Indonesia, a member of the G20, has the sixteenth-largest economy in the world and the largest in Southeast Asia. The economy has been transformed since the country’s independence in 1945. Indonesia has a market capitalist economy with a...

Shopping in Germany can be somewhat baffling because it’s often difficult to predict when a store will or won’t be open. Thankfully, an increasing number of stores are liberalizing their hours. Generally, large stores, supermarkets, and...

In Japan, it is generally expected that women will work for a few years after graduation until children are born. Those with school-age children may go back to work part-time, usually for a low hourly wage. Slowly, however, attitudes are...

South Africa offers a variety of housing options that differ between the major urban centers. Explore neighborhoods and review tips on hiring an estate agent and renting a home.

From its early days of independence, Singapore set about becoming a major player in the competitive world of international business. Since 1968, the economic growth been enviable, and Singapore is among the most competitive nations in...

In this video, we will understand how to create a responsive table.