The nitrogen cycle is essential to life on Earth, but biological nitrogen must be fixed before it can be used. Scientists aren't sure how the first nitrogen became available... but it might have been volcanoes.

In this video Paul Andersen explains how energy is used in chemical processes and everyday life. Students should understand that energy is neither created or destroyed but is converted. Most of the energy is delivered to our planet...

In this video Paul Andersen explains how mass can be converted to energy and energy can be converted to mass. The equation E=mc2 can be used to determine the amount of energy released from nuclear processes.

In this video Paul Andersen explains how the conservation of mass was replaced with the conservation of mass-energy when it was determined that they are equivalent. This famous equation not only show the mass-energy equivalence but can...

In 1165, copies of a strange letter began to circulate throughout Europe. It spoke of a fantastical realm, containing the Tower of Babel and the Fountain of Youth— all ruled over by the letter’s mysterious author: Prester John. Who was...

The energy in the universe never increases or decreases -- but it does move around a lot. Energy can be potential (like a stretched-out rubber band waiting to snap) or kinetic (like the molecules that vibrate within any substance). And...

Although it’s not likely to happen soon, someday gas stations may be replaced by (or turn into) another type of fueling station, because no fuel or mode of transportation is forever

SciShow Space tackles a viewer question: Is the Earth getting heavier? The answers -- there's actually more than one -- may surprise you!

If the human body could be distilled down into one molecule, what would our chemical formula be? And WHY is it that way? There’s a whole lot of elements on the periodic table, but life depends on relatively few of them in order to...

In this video Paul Andersen explains how the total energy of a system is the combination of kinetic, potential and internal energy of the objects. He then shows you how to calculate the kinetic energy, gravitational potential energy,...

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 describes how reversible reactions achieve equilibrium as reactants are converted to products and products are converted to reactants. A model shows how forward reaction rates and reverse reactions rates...

In this video Paul Andersen explains how the law of conservation of energy applies to both energy and mass. Einstein showed that mass and energy are equivalent and that the amount of energy contained within matter can be calculated...

Dietary science is complicated-- one day something is good for you and the next it's not. Learn what we DO know about fat chemistry in this episode of SciShow.

Engineering helped make this video possible. This week we’ll look at how it’s possible for you to watch this video with the fundamentals of signal processing. We’ll explore things from Morse Code, to problems like bandwidth capacity and...

In this video Paul Andersen explains how light can be absorbed, reflected, or transmitted as it moves from one medium to another. The reflection of different wavelengths creates the perceived color of an object. Absorbed light is...

In this video Paul Andersen defines the equilibrium constant (K) and explains how it can be calculated in various reversible reactions. The equilibrium constant is a ratio of the concentration of the products to the concentration of the...

Paul Andersen explains the process of anaerobic respiration. This process involves glycolysis and fermentation and allows organisms to survive without oxygen. Lactic acid fermentation is used in animals and bacteria and uses lactate as...

In this video Paul Andersen explains how the energy in a closed system can be converted from kinetic to potential to kinetic energy. Sample problems and a simulation is contained.

Mr. Andersen explains the difference between potential and kinetic gravitational energy. He also uses physics to calculate the energy in various objects.

Explore the fundamentals of viscosity and how it impacts fluid flow. Learn why water moves easily while ketchup flows slowly through this clear and engaging physics explanation.

2 minute video describing the Law of Conservation and how energy can change forms for middle school science

What Happens To Your Energy when you Die? During the time that you will be watching this video, 500 people around the world will die. Their thoughts, their hopes, their dreams no longer with us. ...

Dive into the fascinating world of fluid flow with this introduction to the four conditions of ideal fluid flow: nonviscous, incompressible, steady, and irrotational. Learn how these principles simplify the complex motions of fluids and...