critical thinking

392

I took this photo near the entrance to Arches National Park. What geologic structure shaped the rocks of this park?

398

This is Carlsbad Caverns. What are the main chemicals involved in the formation of all of those beautiful, flowstone structures?

404

This is Oak Tree House at Mesa Verde National Park, built by Native Americans in the year 1250 A.D. They left no written records, and no verbal history survived, so how do we know so precisely when it was built?

434

I took this photo during a boat ride on the Colorado River. I liked the way the canyon walls reflected in the water near the boat's wake. Since the water was crystal clear, why do you see the reflection of the canyon, instead of seeing through to the bottom of the river?

448

Our friends have a huge crop of hickory nuts this year, and I noticed these in their yard. What do these hickory nuts tell us?

460

Often, as you watch a fireworks display, you will see a large burst that starts as one color, and then the entire burst changes to a different color. How do they do that?

Pages