SciShow takes you inside the site of the world's worst nuclear disaster to show you how, nearly 30 years later, life has adapted and persisted.

Did you know that last year we had 28 of the fastest days ever recorded? Earth's rotation can be affected by a number of things, and scientists think we might someday need an unprecedented adjustment: deleting a second!

Turns out, two atomic clocks are indeed better than one. And what role does sleep play in memory suppression?

Hank throws three bite-sized stories at ya: the sequencing of 5300-year-old ice man Oetzi's genome; a confusing mass of dark matter; and how the cleanup of the Fukushima disaster is going one year later.

Proving something right isn’t just about quantity. It’s also about quality and over the years, scientists have made measurements proving that we understand ridiculously well how the universe works.

Did you know that last year we had 28 of the fastest days ever recorded? Earth's rotation can be affected by a number of things, and scientists think we might someday need an unprecedented adjustment: deleting a second!

It's time for another leap second! Join SciShow as we celebrate by exploring the long and strange history of timekeeping.

In 1967, researchers gathered to answer a long-running scientific question: just how long is a second? It might seem obvious at first. A second is the tick of a clock, the swing of a pendulum, the time it takes to count to one. But how...

Mr. Andersen shows you how to draw Lewis Dot Diagrams for atoms and simple molecules.

Mr. Andersen describes the major groups on the periodic table.

Howcast - Check out part 33 and join the war between the Autobots and Decepticons in Activisions' newest release, Transformers: Fall of Cybertron

Cations, formed by electron loss, influence ionic bond strength. Smaller cations with higher charges create stronger ionic interactions

Electronegativity differences between atoms determine the type of bond: ionic bonds form when the difference is large, while covalent bonds form with similar electronegativity.

Sunflowers are the international symbol for nuclear disarmament. You will most likely find sunflowers around areas where nuclear disasters have occurred in the past. Following the 1986 meltdown at the Chernobyl Power Plant in Ukraine,...

The reactivity of an element is a function of how easily an element loses or gains electrons. To determine an element's reactivity, we can learn a lot from the periodic table, and its particular trends. The first element in the halogen...

What are alkali metals? Why are they so reactive? What are the trends as you go down the group? How do they react with water, oxygen and chlorine? Learn all this and more!

Alexa teaches you ordinal numbers in French

Sunflowers are the international symbol for nuclear disarmament. You will most likely find sunflowers around areas where nuclear disasters have occurred in the past. Following the 1986 meltdown at the Chernobyl Power Plant in Ukraine,...

Main groups in the modern periodic table | Summary

Learn the basics about Group 1, as an example of Groups in the periodic table.

The reactivity of an element is a function of how easily an element loses or gains electrons. To determine an element's reactivity, we can learn a lot from the periodic table, and its particular trends. The first element in the halogen...

It's time to check out Group 1 on the periodic table, the alkali metals. This includes lithium, sodium, potassium, rubidium, cesium, and francium. What can we say about their properties, reactivities, and applications? Let's find out!

What actually are the groups in the periodic table? And why are they structured in that way? Find out the answers in this Chemistry video from The Virtual School.

A look at the chemical properties of elements in group 1 of the periodic table (the alkali metals) showing how the metals react with water, and trends of reactivity and melting point. KS3 and KS4 Chemistry.