Surf's up! Get the current information as Bill Nye explains why oceans are salty and explores the ocean currents. Go with the flow of ocean currents with Bill Nye the Science Guy. Most of the Earth is covered with water - we're talking 71% of the entire Earth, and most of that water is in oceans. It depends how you count, but you can say that there are five oceans on Earth - the Atlantic, the Pacific, the Indian, the Arctic, and the Antarctic. They are all connected into one World Ocean by the flow of ocean currents. Ocean water is moving around all the time. Some of the moving water forms rivers in the ocean. Oceanographers, scientists who study oceans, call these rivers of ocean water "currents". Currents help sea animals move around, they bring up deep ocean water with lots of nutrients for small animals to eat, and they push warm and cold water around, creating different climates in the oceans. As the sea surface gets warmed by the Sun, water evaporates, but salt stays in the sea.

Bill Nye's not here to bug you - he just wants to tell you about insects. Do you know when you're looking at an insect? All insects have six legs, three body segments, antennae, and an exoskeleton. Insects don't have bones. Instead, they have hard shells called exoskeletons. Like a little suit of armor, an exoskeleton protects the insect's body and also keeps it from drying out. Although people call any crawling critter with an exoskeleton a "bug", the "true bugs" are insects that have special mouth parts for piercing and sucking. And, spiders are not bugs or even insects. They're built differently with only two main body parts and eight legs instead of six. If you think you have a wild time growing up, take a look at an insect's life. Most insects go through at least four stages of growth -- egg (little round thing), larva (a bit like a worm), pupa (insect in a cocoon), and adult. It's a long road to maturity for an insect. Everyone's buzzing about the "Insects" episode. Don't miss it

Bill Nye's going to use the force to pull you into the world of balance. A force is a push or a pull. You can feel a force when someone pushes you. You can use a force to pull a door shut. Anyone can make forces by pushing and pulling, and you don't need to be Luke Skywalker to use a force. In a game of tug-of-war, if the pull of your team is the same as the pull of the other team, the forces are equal. The two teams are in balance, and the rope doesn't budge. Things are in balance when forces that are pushing or pulling them are equal. If your tug-of-war team pulls harder than the other team, the forces are not equal. The other team falls all over the place. Unequal forces make things move and twist. A lot of things are designed to take advantage of unequal forces. Wrenches, screwdrivers, door handles, and water faucets use forces made by you to do work. A well-balanced science diet starts with Bill Nye.

In this program, Bill points out the different ways in which humans and animals exchange information. He also talks about the ability of humans to store data in computers, books, and on videotapes.

Bill Nye teaches us about reptiles.

We live on top of rocks – the Earth’s surface. There are three basic types of rocks — igneous, sedimentary, and metamorphic — and each type is made a different way. Igneous rocks are made from cooled lava. Sedimentary rocks are made from small pieces of other rocks stuck together. Metamorphic rocks are formed when other rocks are heated or pressed, or both. One type of rock can change into another type of rock as the Earth’s surface shifts and changes. It takes the right conditions and a lot of time.

Energy can change forms. Your body changes the energy in food into energy you can use to do things. Dams turn the energy in falling water into electrical energy to bring power to your house. Sound energy changes into moving energy (like when the bass is so high you can feel the floor move).

Don’t panic, but germs are all around you. Germs are bacteria, viruses, protozoa, and fungi, very small one-celled organisms. Your skin keeps most of these organisms from ever getting into your body. If germs slip inside, your body has some powerful weapons to attack and destroy them. And not all germs are bad; there are good germs, too, like the ones that live in our stomach and intestines – our guts.

Energy, things like light, heat, and sound, moves in waves. You’ve probably seen waves in the ocean, or ripples when you throw a rock in a pond. Moving energy is not like the wave you do with your hand.

A lot of things spin – bike wheels, footballs, hard disks in your computer, and even the Earth – they’re all twirling around. Spinning things have inertia, which means they keep spinning unless something slows them down. Bike tires keep spinning until you put on the brakes. A football spirals through the air until you catch it. The Earth keeps on spinning 24 hours a day, seven days a week. It’s been spinning for over four billion years.

More than 22,000 different species of fish live in the oceans, lakes, and rivers of the world. Fish come in all shapes and sizes. Some eat water plants, some eat other fish. Lampreys and some jawless fish suck onto other fish for food. Stone fish live on ocean bottoms and camouflage themselves as rocks. Puffer fish blow themselves up like a balloon, only they’re covered with spines. There are tons of strange and cool-looking fish everywhere.

Transportation is all about moving people and their things. You can transport yourself around using your feet, a bike, a car, a train – anything that gets you going from one place to another. Humans have been moving around from place to place ever since they’ve been on Earth. That’s how we get our food and our materials like lumber, concrete and computers from one place to another.

Wetlands are not just home to different animals and plants, but they also control flooding and help keep the Earth’s water clean. Flood waters move more slowly through wetlands because they have to go through barriers of plants and dirt. Wetlands help stop erosion because the plants stop the soil from washing away. Plants and soil in wetlands slow water enough that bacteria and other decomposer organisms can break down and even absorb some types of pollution. Wetlands are wet. Let’s keep them that way.

Scientists believe that birds evolved from reptiles. Birds have backbones, and they lay eggs, but they’ve developed a unique feature that sets them apart from all other animals – feathers. Feathers are made of the same stuff human fingernails and hair are made from – a protein called keratin. Feathers, combined with lightweight bones, powerful wings and strong hearts let birds fly.

Earthquakes happen when pieces of land in the Earth’s crust scrape together. The crust of the Earth is made of big slabs of land called plates that are constantly moving just a little bit. The plates scrape by one another, and sometimes they don’t move smoothly. An earthquake happens when the plates get unstuck suddenly and jerkily slip past each other. The majority of earthquakes occur along plate boundaries such as the boundary between the Pacific Plate and the North American plate. One of the most active plate boundaries for earthquakes is the massive Pacific Plate commonly referred to as the Pacific Ring of Fire. The fire comes from the volcanoes that form near the edge of the plates.

Join Bill Nye as he counts down the hits from the Soundtracks of Science. Along with the music, Bill does a few new experiments on the lab bench. You’ll see the grunge band Nyevana’s classic “Air Pressure,” Momentisey’s “The Faster You Push Me,” and divas En Lobe’s “Whatta Brain.” There’s even a special appearance by Mudhoney, a real band from Seattle. But if you want to know who’s the number one artist from Not That Bad Records, you’ll have to tune in.

Be sure to get this straight: spiders are not insects, they’re arachnids. Spiders have eight legs, and insects have only six. Spiders have two body parts, a head and an abdomen, while insects have three body parts, a head, a thorax, and an abdomen. Insects have antennae, and spiders do not. Some insects sting. All spiders have fangs and venom. There are almost certainly a few spiders in the room with you right now.

About 20% of the Earth is a desert. Deserts are places that get very little precipitation (rain or snow) each year, and that makes them extremely dry. Deserts cover big areas of land. The biggest desert, the Sahara, extends from North Africa to Southwest Asia and is 13 times the size of Texas. Some parts of the Sahara get as little as 2 millimeters (0.08 inches) of water a year.

With special guest, Mick H. Computers are used throughout the world all the time. Computers are in cars, calculators, televisions – you’re even using one right now. Humans use computers to take information – things like pictures, words, numbers, and sound, and turn it into electricity. The information is changed into a pattern of electrical pulses, a bunch of electricity “ons” and “offs.” The computers are designed so that they can tell the difference between pieces of information by the different patterns of “ons” and “offs.” Computers change the information you give them, turn it into electrical pulses, make changes to it, and give it back to you in a form you can understand in a matter of thousandths of seconds. It’s not the computers, it’s the electricity that makes computers so fast.

Forensic scientists try to find out the who, what, when, where, and why of events in the past – crimes. Most forensic scientists work in police labs. They collect evidence from the scene of a crime and analyze the evidence in a lab. Forensic scientists look for clues that will help them solve a crime. Fingerprints, footprints, hair, blood, and traces of gunpowder can be helpful evidence. Forensic scientists use all sorts of scientific instruments to analyze even the smallest bit of hair or the tiniest chip of paint. By scientifically testing evidence from the crime scene, and by knowing about evidence from past cases, forensic scientists can piece together what happened, to figure out who did what, and to help police catch a criminal.

Before food gets into your kitchen, before it even gets to the store, it’s on a farm. Almost everything we eat is grown on a farm, an area of land used to raise animals and plants. Farming nowadays can get pretty complicated. Farmers are scientists – agricultural scientists. Farmers work hard to keep their farms healthy. Soil is stirred up to get oxygen to the microorganisms that live in between the grains and to plant roots – that’s called tilling the soil to aerate it. Plants need to be protected from pests with either chemical pesticides or biological pesticides. Animals like bats and friendly insects eat other pest insects (chomp,chomp). Animals are milked, corralled, fed, sheared, slaughtered or cleaned-up after.

Ocean exploration is a tricky, risky business since humans can’t naturally survive under the ocean. Ocean explorers are constantly inventing new tools to help them dive deep into the sea. Over the last few hundred years or so, and especially in the last few decades, we humans have come up with all kinds of new ways to study the ocean. Even so, the ocean remains largely unexplored. It’s huge, cold, salty, and deep. Ocean exploration helps us understand our planet, and may help us solve the mystery of how life started on Earth.

Caves come in all different shapes and sizes depending on how they were formed. Spelunkers (people who explore caves) have plenty of descriptive names for caves and the natural rocky features that form within them – soda straws, fried eggs, popcorn and draperies are just a few. Caves can be as simple as one straight passage with a few stalactites overhead, or as complex as a labyrinth, with many stalagmite-carpeted rooms.

Did you know that the Concorde moves 300,000 times faster than a land snail? Or that a giant redwood can be as tall as a 35-story apartment building? The only reason we can make these comparisons is because people have measured these things. We don’t compare jets and snails every day, but we do rely on measurement constantly. When you take your temperature, you find out how it compares to the temperature of someone who is healthy. When you bake brownies, you’ll need to measure the ingredients first to make sure they turn out tasty. Using measurement, we can make useful comparisons of distance, time, mass, and temperature.

Every time you look at something, hear something, touch something, smell something, or taste something, your brain collects a little information about the world around you. You may even have a scrapbook to store memories of some of that information. There’s a lot out there though. How do people sort out the valuable information from the not-so-valuable?