Social entrepreneur Julie Cordua works on a problem that isn't easy to talk about: the sexual abuse of children in images and videos on the internet. At Thorn, she's building technology to connect the dots between the tech industry, law...

In the card game SET, what is the maximum number of cards you can deal that might not contain a SET?

In this video Paul Andersen explains how contour lines show areas of equal elevation or equal gravitational potential. Contour lines are used as an analogy for lines of equipotential in electric fields.

Reading and writing can be acts of courage that bring us closer to others and ourselves. Author Michelle Kuo shares how teaching reading skills to her students in the Mississippi Delta revealed the bridging power of the written word --...

If you play video games, you've shot a gun. And those guns are REALISTIC. So real that many are actually LICENSED by IRL arms dealers. Which means that when you buy a video game, you're also putting money in the pockets of those gun...

How do you think about the column space and null space of a matrix visually? How do you think about the inverse of a matrix?

A geometry/probability question on the Putnam, a famously hard test, about a random tetrahedron in a sphere. This offers an opportunity not just for a lesson about the problem, but about problem-solving tactics in general.

In which John Green teaches you about the beginning of the so-called Age of Discovery. You've probably heard of Christopher Columbus, who "discovered" America in 1492, but what about Vasco da Gama? How about Zheng He? Columbus gets a bad...

Today we’re going to discuss how 3D graphics are created and then rendered for a 2D screen. From polygon count and meshes, to lighting and texturing, there are a lot of considerations in building the 3D objects we see in our movies and...

Physicist Geoffrey West has found that simple, mathematical laws govern the properties of cities -- that wealth, crime rate, walking speed and many other aspects of a city can be deduced from a single number: the city's population. In...

The enigmatic equation e^{pi i} = -1 is usually explained using Taylor's formula during a calculus class. This video offers a different perspective, which involves thinking about numbers as actions, and about e^x as something which...

Paul Andersen explains how a respirometer can be used to measure the respiration rate in peas, germinating peas and the worm. KOH is used to solidify CO2 produced by a respiring organism.

The idea that a collection of pixels can be sold for actual money might be confusing to some, as they are neither true "objects" you can hold nor "ideas" that can be considered intellectual property. But despite the lack of tangibility,...

Musician and activist Bono accepts the 2005 TED Prize with a riveting talk, arguing that aid to Africa isn't just another celebrity cause; it's a global emergency.

The enigmatic equation e^{pi i} = -1 is usually explained using Taylor's formula during a calculus class. This video offers a different perspective, which involves thinking about numbers as actions, and about e^x as something which turns...

What would Immanuel Kant say about a fender bender? In a surprisingly funny trip through the teachings of some of history's great philosophers, TV writer and producer Michael Schur (from hit shows like "The Office" and "The Good Place")...

A new strain of the E. coli bacteria seems to have become resistant to most antibiotics. Let’s talk about how this possibly happened.

This is an absolutely beautiful piece of math. It shows how certain ideas from topology, such as the mobius strip, can be used to solve a slightly softer form of an unsolved problem in geometry.

In a series of mind-bending demos, inventor Mary Lou Jepsen shows how we can use red light to see and potentially stimulate what's inside our bodies and brains. Taking us to the edge of optical physics, Jepsen unveils new technologies...

This is an absolutely beautiful piece of math. It shows how certain ideas from topology, such as the mobius strip, can be used to solve a slightly softer form of an unsolved problem in geometry.

You might be familiar with the concept of self-harm, but it isn’t just physical. As it turns out, people can harm themselves through the anonymity of the internet.

If you’ve watch American football on television, you may have wondered how they make that yellow first down line look like it’s actually down on the field.

In a talk about how we can build a robust future without wrecking the planet, sustainability expert Johan Rockstrom debuts the Earth3 model -- a new methodology that combines the UN Sustainable Development Goals with the nine planetary...

Margaret Wertheim leads a project to re-create the creatures of the coral reefs using a crochet technique invented by a mathematician -- celebrating the amazements of the reef, and deep-diving into the hyperbolic geometry underlying...