Natural selection plays a large role in the evolution of a species. The following activity demonstrates this concept.

It's not what they ate or when they lived that distinguishes dinosaurs from other reptiles. It's the hole in their hip socket. Find out how this feature affected the way dinosaurs walk.

Can you walk like a dinosaur? Hint: The movement is not like lizards, crocodiles, and other reptiles; instead, it's more like birds. Investigate what else birds and dinosaurs have in common.

What kind of fossil is a tooth—body or trace? How about a nest of eggs? Or a skin impression? Examine the differences between body and trace fossils with these eight high-quality photographs.

Re-create the 130-million-year-old forest in what is now China to understand why this fossil site is of such vast scientific importance.

Explore the method scientists use to determine evolutionary relationships by creating a coin cladogram. Then try your hand at classifying a handful of dinosaurs.

While refracting and reflecting telescopes use different means of collecting light, the same principle applies to both—the bigger the aperture, the more light collected.

What could Galileo see when he looked through his telescope? Build a refracting telescope with lenses similar to the ones he used, and see the answer for yourself.

No doubt you've received—or even sent—a digital image. But do you know how these pixel-based photographs work? You will after you decode one yourself.

A picture is worth a thousand words, but whose words are they? Zoom in on how the opinions and biases of photographers can color the images they take.