Cycles are a big deal in engineering. Today we’ll explain what they are and how they’re used in heat engines, refrigerators, and heat pumps. We’ll also discuss phase diagrams and the power of using renewable energy resources

How to Build a Better City

A broken bone might seem worse than a sprain, but you'll get over it much more quickly.

Empire, imperialism, and colonialism are all interrelated tactics of geopolitics that are used to achieve similar goals of one state maintaining economic, political, or even cultural dominance over other territories. Today, we’re going...

In this video Paul Andersen explains the important relationships that exist in ecosystems. He starts by delineating between organisms and their environment. He explains how food webs can be used to show energy and matter flow in a...

In which Craig Benzine teaches you about federalism, or the idea that in the United States, power is divided between the national government and the 50 state governments. Craig will teach you about how federalism has evolved over the...

If you compare precipitation around the world with population distribution we can understand a simple but powerful pattern of human geography: where there is water, there are people. But it gets a little more complicated because where...

There's two times more carbon in the earth's soil than in all of its vegetation and the atmosphere -- combined. Biogeochemist Asmeret Asefaw Berhe dives into the science of soil and shares how we could use its awesome carbon-trapping...

Today we’re going to talk about the link between population and food energy. As the world's population keeps growing, finding ways to provide enough food and water for everyone while supporting a sustainable environment can be tricky! ...

Is the world overpopulated or underpopulated? While we worry about there being too many people for the planet to support, we can also worry about how fewer people in a given place may affect the economy, what may happen when there are...

As engineer, sometimes lives will be in your hands, so this week we’re exploring safety and its impact on engineering. We’ll discuss the difference between occupational safety and public safety and how to analyze and review a process for...

In which Adriene Hill and Jacob Clifford teach you about one of the fundamental economic ideas, supply and demand. What is supply and demand? Well, you'll have to watch the video to really understand it, but it's kind of important for...

If being alive on Earth were a contest, humans would win it hands down. We're like the Michael Phelps of being alive, but with 250,000 times more gold medals. Today Hank is here to tell us the specifics of why and how human population...

In which Jacob Clifford and Adriene Hill launch a brand new Crash Course on Economics! So, what is economics? Good question. It's not necessarily about money, or stock markets, or trade. It's about people and choices. What, you may ask,...

Mae Jemison is an astronaut, a doctor, an art collector, a dancer ... Telling stories from her own education and from her time in space, she calls on educators to teach both the arts and sciences, both intuition and logic, as one -- to...

In which John Green teaches you about the Democratic Republic of the Congo, which used to be Zaire, which used to be The Belgian Congo, which used to be the Congo Free State, which used to be the region surrounding the Congo River Basin...

Day to day, hospitals provide all kinds of services to help us get better and stay healthy, but during an outbreak, hospitals are the front line of the emergency. In this episode of Crash Course Outbreak Science, we'll look at how...

When someone says they’re “studying business” or they “work in business,” they could mean so many different things. They could be in marketing, sales, finance or human resources. So much goes into keeping a company running smoothly.

Interactions between species are what define ecological communities, and community ecology studies these interactions anywhere they take place. Although interspecies interactions are mostly competitive, competition is pretty dangerous,...

In this video Paul Andersen explains how the resources required for survival come from the Earth. The resources are not evenly distributed on the planet and neither are the humans. According to the NGSS we need to limit the use of...

Welcome to Crash Course Outbreak Science! What do pathogens actually do to us that makes us sick? Why do societies respond to outbreaks of infectious diseases the way they do? How can we stop the next outbreak? These are the kinds of...

So... do plants need dirt? The truth might shock you. In this episode of Crash Course kids, Sabrina talks about how plants get energy and how that energy is transported around them. Also, she talks about dirt.

You may have heard several different projections about the fatality rate of COVID-19. How do different health organizations come up with these figures, and why do the numbers seem so fluid?

What happens to a single ecosystem when the amount of freshwater available in it changes? Not really much good. In this episode of Crash Course Kids, Sabrina talks about ecosystems and how one small change can lead to a cascade effect in...