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...

Explore the science behind thermometers. Rather than measuring temperature, thermometers track the movement of heat from hot to cold. The installment of the ACS Reactions series examines the chemical response that make thermometers work.

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,...

Students 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 acidic...

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...

Are the depictions of the colorful raptors in Jurassic Park accurate? No so much. Imaginative, but not scientific. Find out how researchers determine the color of dinosaur feathers in this short, entertaining video.

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...