TOKYO — How powerful are hydrogen bombs? Think of it this way: They use atomic bombs just as a trigger. Atomic weapons like those previously tested by North Korea rely on nuclear fission to release ...

Atoms are the building blocks of matter. Everything around us — from air and water, to rocks, plants and animals — as well as everything within our bodies, is made up of atoms. They are very small, ...

Note: This video is designed to help the teacher better understand the lesson and is NOT intended to be shown to students. It includes observations and conclusions that students are meant to make on ...