Tell students that this is another model of a water molecule. In this model, color is used to show the polar areas of the water molecule. The negative area near the oxygen atom is red, and the ...

Most of the universe’s hydrogen and helium atoms formed around 400,000 years after the Big Bang, which is the name for when scientists think the universe began, about 14 billion years ago.

Hydrogen is the lightest and one of the most common atoms in the universe, usually found bonded in twos, but it’s difficult to isolate. Today, companies generate hydrogen by applying steam to ...

Once the universe had sufficiently expanded and cooled, however, subatomic particles could acquire electrons to form neutral hydrogen atoms, and the cosmic dark ages began.