- HI THERE.

I'M DR. SCOTT THE PALEONTOLOGIST.

WASN'T IT FUN WATCHING THE PTERANODON FAMILY FLY AROUND IN A ZEPPELIN?

WHAT A GREAT WAY TO CHECK OUT THE SIGHTS FROM WAY ABOVE THE EARTH, AND SOME OF THE MOST BEAUTIFUL SIGHTS IN THE WORLD ARE WATERFALLS.

WATERFALLS FORM WHEN A STREAM OR A RIVER FLOWS OVER A CLIFF.

MANY WATERFALLS, LIKE THE RIBBON FALLS IN THE GRAND CANYON, ARE THIN AND DELICATE.

OTHERS, LIKE NIAGARA FALLS, ARE HUGE AND POWERFUL!

WOW!

AND HOW ABOUT THE EVEN BIGGER IGUACU FALLS IN ARGENTINA?

THE IGUACU FALLS ARE SOME OF THE LARGEST IN THE WORLD, MAKING A CURTAIN OF WATER ALMOST TWO MILES WIDE.

WATERFALLS OF ALL SIZES CAN BE GREAT SOURCES OF ENERGY.

A LONG TIME AGO, PEOPLE USED WATER MILLS TO RUN MACHINES THAT MADE THINGS LIKE LUMBER AND FLOUR.

MORE RECENTLY, WE'VE LEARNED HOW TO BUILD HUGE HYDROELECTRIC DAMS THAT TURN WATER POWER INTO ELECTRICITY.

WE USE THAT ELECTRICITY TO HEAT AND COOL OUR HOMES.

NOW, GET THIS: THE LARGER THE WATERFALL, THE MORE POWERFUL IT IS-- AND THE LOUDER IT IS.

SOME WATERFALLS ARE SO LOUD, THEY CAN BE HEARD FOR MILES AWAY!

LISTEN TO THESE FALLS!

PRETTY LOUD, HUH?

[water crashing] OKAY, REMEMBER, GET OUTSIDE, GET INTO NATURE, AND MAKE YOUR OWN DISCOVERIES.