Asking questions almost always leads to finding answers, but those answers will often pose even more questions. Here are five mysteries started and later solved by science.

The event that killed the dinosaurs 66 million years ago might be the most famous mass extinction ever, but it's not the only one in Earth’s history, nor is it the worst... not by a long shot.

Can a paper bag really help you when you are hyperventilating? It turns out that it can. In part 2 of our look at your respiratory system Hank explains how your blood cells exchange oxygen and CO2 to maintain homeostasis. We'll...

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.

The Great Dying hit life hard, but the species that survived took over the planet and diversified into many interesting forms, including the dinosaurs!

The ground beneath your feet is home to a massive, mysterious world of microbes -- some of which have been in the earth's crust for hundreds of thousands of years. What's it like down there? Take a trip to the volcanoes and hot springs...

We've already learned a lot about the solar system, but sometimes the most fascinating things are what we DON'T know.

Wouldn’t it be wonderful if we could breathe underwater? But is it even possible?

How Do Greenhouse Gases Actually Work?

Phil starts the planet-by-planet tour of the solar system right here at home, Earth.

The Carbon Impact of the World’s Largest Mass Migration

From the starter plants in your window to giant agriculture, there's a lot of science to cover before dinner.

Given that Earth’s magnetic field helps protect its life-sustaining atmosphere, you might think that the stronger a planet’s magnetic field, the better. But as it turns out, some planets’ relationships with their magnetic fields are a...

Antarctica wasn't always covered in kilometer thick ice sheets, in fact, scientists have spent years figuring out what turned this once lush continent into its current icy state.

Hank talks about a sweet-tasting substance we humans just love - where it comes from, why we need it and how we could maybe stand to love it a little less.

Crocodiles have four-chambered hearts, just like we do! But, while our hearts do just fine with four valves, they have a slightly different approach…

This week we are exploring alternative energy sources. We'll look at how biomass can be burned as a fuel source, how hydrogen can be used in a fuel cell to generate electrical power, and how nuclear fission provides power to the grid....

We’d pictured the plant-fruit relationship as one-way, but new research reports that sometimes the fruit can talk back! And while cow burps are a widely cited contributor to climate change, it turns out that wild pigs might also be...

So you know that iced tea you like so much? Or that sweet soda drink? They're actually a few different things combined to make a new thing. In this episode of Crash Course Kids, Sabrina talks about all the different mixtures, solutions,...

If we ever want to live, sleep, eat, and breathe on Mars, we are going to need some the best tech humans can dream up - and as a bonus that tech might actually help tackle challenges right here on Earth!

How is it possible for air-breathing marine mammals like sperm whales and elephant seals to hold their breath for so long?

In this video Paul Andersen explains how chemical differs from physical change. In the laboratory macroscopic observations are used to infer changes at the particulate level. Evidence for chemical change include gas production, change...

We’ve all heard the phrase “opposites attract.” It may or may not be true for people, but it’s definitely true in organic chemistry. In this episode of Crash Course Organic Chemistry, we’re learning about electronegativity, polarity,...

Paul Andersen explains how cells are selectively permeable with the help of their cell membrane. The main constituents of the cell membrane, including cholesterol, glycolipids, glycoproteins, phospholipids, and proteins are included. ...