Nature’s Surprises: From Spider Silk to Ice That Floats

Ever Wonder How Dolphins Swim?
Dolphins are mammals that live in the water, but they swim just like fish and sometimes even better. Their tails move up and down, helping them glide smoothly through the water. Their fins help them turn and steer as they swim long distances with ease.

Do You Know What Spider Silk Is Made Of?
Spiders spin webs to catch insects, which they eat. These webs are made of protein and are actually one of the strongest natural materials. The silk comes from special glands at the bottom of the spider’s body.

Have You Seen the Yellow River?
The Yellow River in China flows from the Bayan Har Mountains in the west to the Bohai Sea in the east. It’s the second-longest river in China and the sixth longest in the world. The water looks yellow because it carries fine yellow soil called loess along its path.

Ever Thought About Why Ice Floats?
Most things get smaller when they get cold, but water is different. When it freezes, it actually expands and becomes lighter than liquid water. That’s why ice floats. This special feature helps fish and other animals survive under frozen lakes, because the ice forms a blanket that keeps the water below from freezing completely.

Do You Know Where Skydivers Leap Into a Cave?
In Mexico, there’s a giant cave called the Cave of Swallows. It has the largest cave shaft in the world and so big that the Eiffel Tower could fit inside! It’s not the deepest cave, but it’s wide and deep enough that skydivers sometimes parachute into it, just like jumping from a plane.