FD: v4 (Second Timers)

HARBOR SEALS: The harbor seal will follow water turbulences caused by fish. The fish can be 300 feet away! Ten seconds after a fish passes by, the harbor seal can follow the exact turbulence trail left by the fish and catch it. Its flipper hairs are so sensitive that it can do this.

HARBOR SEALS: Harbor seals are the master trackers of the sea. Their astonishing tracking abilities rival the amazing abilities of caterpillar moth on land.

HARBOR SEALS: Unlike bloodhounds, harbor seals don’t track scent. Rather, they track the slight disturbances in the water left behind by other sea creatures. The harbor seal is so good at underwater turbulence tracking that scientists believe he can tell the type of fish he’s following from 300 feet away by the prey’s water trail.

HARBOR SEALS: A harbor seal can track another seal several minutes after it has passed, just by following the extremely faint trail of turbulence left in the water. This turbulence is like the ripples left by a power boat. How many times fainter is this turbulence than the ripples left by a power boat?

HARBOR SEALS: The harbor seal does this tracking by turning his whiskers perpendicular to the water-turbulence trail he is following. Complex messages are then sent to his brain from the whisker sensors. The brain has a large part of itself dedicated to analyzing these messages.

JET CRASH: Executives from the In-and Out hamburger chain died in a plane crash when their jet was flipped by the turbulence of a 747 jet 3 miles ahead of them!

ALULAS AND AILERONS: When a jet slows to land, the lift pushing it upward decreases. A jet needs the help of moving flaps on its wings help to keep it in the air. The movement of alula feathers on birds’ wings helps them with lift also while landing. They help birds to land elegantly.

ALULAS AND AILERONS: The alula feathers are attached to a tiny bone in the back of the bird’s wing. They stick out at exactly the right moment giving the bird extra lift.

ALULAS AND AILERONS: Particle image velocimetry was used to study the effect of the alula feathers. Particles were sprayed into the air where birds were landing. It was discovered that small vortices were caused by the alula feathers that helped birds to land elegantly. These vortices kept the air molecules hugging the wing further back as it passed over it.

ALULAS AND AILERONS: At Oxford, scientists learned that the steppe eagle has a very fast movement of feathers across the shoulder of its tail just as it is about to land. This gives the bird extra lift. Scientists are now investigating the idea of using sideways moveable ailerons.