It's a gas! Air consists of nitrogen and oxygen and lots of empty space.
The part of our eyes we use to see fine detail, and to read, is actually very limited: an angle of five degrees at the center of our field of vision.
The oldest archaeological sites showing tar use are about 200,000 years old.
An explainer post about flu strains, vaccines, and why people are saying this year's vaccine may have only been ten percent effective.
Learn how to make bubbles that will freeze in cold temperatures.
The Geminid Meteor Showers peak on December 13th and 14th 2017.