How Do We Know Which Trees to Tap?

Eight neat slides lead to the understanding of how geologists have determined Earth's age. Most of the slides are dedicated to explaining the absolute dating method of assessment. Color diagrams display radioactive isotopes and a graph...

Continents are on the move! An engaging lesson explains the acceptance of the idea of continental drift. The narrator of the It's Okay to Be Smart "Earth Science Videos!" installment considers the convincing evidence of the concept. 

The big question is, how do we know about the composition of the earth's core? Sal explains that at 105 degrees from the source point of an earthquake the phenomena of p wave shadow zone leads us to conclude that the waves are traveling...

It seems like a simple process: we breathe in, our nose detects different scents, and our brain interprets the smell. But how does it actually work? How can something smell like vanilla to one person, but like urine to someone else? How...

How do scientists know what they do about evolution? Looking at fossilized data, paleontologists examine fossils to show the evolution and changes that developed into modern whales. We find out that scientists use physical evidence,...

Out of all vertebrates, the largest brain when compared to body size belongs to humans. Studying the working brain presents challenges to scientists. Learn about three of the most common tests used to understand how the living brain...

Young scholars think of one way to detect photosynthesis in plants besides those ways shown in class. They identify the reaction that occurs during photosynthesis. Students define the difference between an acid and a base. They identify...

Scientists measure dark matter based on gravity, but how do we find something that can't be detected by anything on the electromagnetic spectrum? Understanding what doesn't work leads to new tests and machines in the search for dark...

If you've ever had an injection, the horseshoe crab protects you from infection! Young marine biologists discover how scientists use the unique physiology of the horseshoe crab in medicine with a thought-provoking video. The narrator...

The big question is, how do we know about the composition of the earth's core? Sal explains that at 105 degrees from the source point of an earthquake the phenomena of p wave shadow zone leads us to conclude that the waves are traveling...