Paul Andersen introduces the topic of Biology. He covers each of the four main ideas that were developed by the College Board. These ideas revolve around the concepts of evolution, free energy, information and systems.

Bacteria "talk" to each other, sending chemical information to coordinate attacks. What if we could listen to what they were saying? Nanophysicist Fatima AlZahra'a Alatraktchi invented a tool to spy on bacterial chatter and translate...

You may have heard about a study that found pigeons can visually recognize what printed words look like. Does that mean these birds can read?

There's a job out there with a great deal of power, pay, prestige, and near-perfect job-security. And there's only one way to be hired: get appointed to the US Supreme Court. But how do US Supreme Court Justices actually get that honor?...

Dr. Ivan Pavlov's groundbreaking work revealed that a dog will respond to neutral stimuli, such as a bell, in the same way that it will respond to, say, mouth-watering food. This research is widely applicable beyond a dog's salivation....

Mr. Andersen explains how carbon-14 dating can be used to date ancient material. The half-life of radioactive carbon into nitrogen is also discussed.

In this video Paul Andersen explains how the second law of thermodynamics applies to reversible and irreversible processes. In a reversible process the net change in entropy is zero. In and irreversible process the entropy will always...

Over the course of human history thousands of languages have developed from what was once a much smaller number. How did we end up with so many? And how do we keep track of them all? Alex Gendler explains how linguists group languages...

For as long as we've had language, some people have tried to control it. And some of the most frequent targets of this communication regulation are the ums, ers, and likes that pepper our conversations. These linguistic fillers occur...

We've all got bad habits that we might feel a little bad about, but we're here to tell you stop feeling guilty! Kind of.

You use paper towels to dry your hands every day, but chances are, you're doing it wrong. In this enlightening and funny short talk, Joe Smith reveals the trick to perfect paper towel technique.

In this video Paul Andersen explains how the reaction path can be described in an energy profile. Enough energy must be added to reach the activation energy required and stress the bonds. Eventually the bonds break and new bonds are...

Paul Andersen explains how biogeochemical cycling is used to move nutrients from the environment into living material and back again. He explains the water cycle, the carbon cycle, the nitrogen cycle and the phosphorus cycle. He also...

In this video Paul Andersen explains how the wave speed measure the speed of a wave through a medium. The medium determines the speed of the wave. The velocity of the wave is equal to the product of the wavelength and the frequency of...

The aggressive urges you might have when you see adorable things are probably related to the way you handle strong emotions.

This animation is part of the TED-Ed series, "There's a Poem for That," which features animated interpretations of poems both old and new that give language to some of life's biggest feelings. [Poem by Brendan Constantine, directed by...

Today, Clint Smith will teach you about the legendary writer Toni Morrison. Morrison is best known for her novels which chronicle the experiences of Black Americans throughout history. She was the first Black American Woman to win a...

The average 20-year-old knows between 27,000 and 52,000 different words. Spoken out loud, most of these words last less than a second. With every word, the brain has a quick decision to make: which of those thousands of options matches...

In this podcast Paul Andersen explains how cells differentiate to become tissue specific. He also explains the role of transcription factors in gene regulation. The location of a cell within the blastula ultimately determines its fate....

Hannah Brencher's mother always wrote her letters. So when she felt herself bottom into depression after college, she did what felt natural -- she wrote love letters and left them for strangers to find. The act has become a global...

In this video Paul Andersen explains how forces on an object always require another object. An object cannot exert a force on itself. If net forces on an object are balanced the object will remain at rest or move with a constant...

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

They say the pen is mightier than the sword, and authorities have often agreed. From outlawed religious tracts and revolutionary manifestos to censored and burned books, we know the potential power of words to overturn the social order....

You know what's amazing? That we can talk to people, they can make meaning out of it, and then talk back to us. In this episode of Crash Course Psychology, Hank talks to us and tries to make meaning out of how our brains do this thing...