In this video Paul Andersen explains how classical waves (like light) can have particle properties. Albert Einsetein used the photoelectric effect to show how photons have particle properties.

How counting in Ternary can solve a variant of the Tower's of Hanoi puzzle, and how this gives rise to a beautiful connection to Sierpinski's triangle.

In this video Paul Andersen explains how the energy, charge, and momentum in a system is conserved over time.

Today we’re going to talk about measures of central tendency - those are the numbers that tend to hang out in the middle of our data: the mean, the median, and mode. All of these numbers can be called “averages” and they’re the numbers...

Fire seasons can be bad enough on their own, but it turns out sometimes forest fires that appeared to be dead, turn out to have just been lying in wait.

Hank gets to the bottom of two studies reporting high sea ice coverage and snowmass in Antarctica in the same year that the Arctic has reported a record low of sea ice. What is going on here?

Airplanes use a lot of fuel, which means a lot of CO2 emissions. So, to help reduce the impact of aviation, engineers are looking to animals (like sharks) for some ways they can make airliners more efficient.

Modern buildings with floor-to-ceiling windows give spectacular views, but they require a lot of energy to cool. Doris Kim Sung works with thermo-bimetals, smart materials that act more like human skin, dynamically and responsively, and...

Sitting down for brief periods can help us recover from stress or recuperate from exercise. But nowadays, our lifestyles make us sit much more than we move around. Are our bodies built for such a sedentary existence? Murat Dalkilin�c...

In 2013, astronomers reported that they'd found what was, at the time, the biggest thing in the known universe.

The human body has a few built-in methods for getting rid of toxins. Sweating seems like it should be one of them, but it isn't doing as much as you think.

In this video Paul Andersen explains how the electric field strength decreases as the square of the radius as you move away from a point charge, or a uniform distribution of charge on a sphere. This is a direct application of Coulomb's...

After drinking a few glasses of water on a hot day, you might be struck with a sudden urge. Behind that feeling are two bean-shaped organs that work as fine-tuned internal sensors. Emma Bryce details how the incredible kidneys balance...

In this video Paul Andersen explains how heating is the transfer of energy (heat) from a warmer object to a cooler object. Heat can be transferred through conduction, convection and radiation. At the microscopic level conduction...

Do you know how many people have been to the moon? Only 12! Part of the reason it's so few is because of how difficult it is to escape Earth and get into space in the first place. In this episode of Crash Course Kids, Sabrina talks about...

All humans want to be comfy, but the first air conditioner wasn't built for us--it was for a printing press!

The laws of thermodynamics are cornerstones of physics - but one of them is more breakable than it appears.

Too often we think of air as empty space - but compared to a vacuum, air is actually pretty heavy. So, just how heavy is it? And if it's so heavy, why doesn't it crush us? Dan Quinn describes the fundamentals of air pressure and...

How to think about implicit differentiation in terms of functions with multiple inputs, and tiny nudges to those inputs.

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