The first time we find evidence of life on a planet orbiting another star (an exoplanet), it is probably going to be by analyzing the gases in its atmosphere. With the number of known Earth-like ...

Hydrogen is an element; it exists naturally as a molecule. Each hydrogen molecule is made up of two hydrogen atoms. In hydrogen cars hydrogen reacts with oxygen in a fuel cell, making electricity to ...

Chemical reactions occur when elements or compounds combine and create new compounds. Elements are substances that contain only one type of atom and are represented by unique symbols on the periodic ...