Dinosaurs lived millions of years ago. They were around for 150 million years. Movies often show dinosaurs as giant, scary lizards. But real dinosaurs actually looked quite different. They were a diverse group with various shapes and sizes. Many dinosaurs looked more like birds than lizards. Take the velociraptor, for example. In movies, this dinosaur looks bigger than a person. Its claws and teeth look long and sharp. But, in fact, velociraptors were not that big or that scary. They were about the size of a turkey. And they were also covered in feathers. They did not look scary at all.

How did we learn about the dinosaurs? We learned from fossils. Fossils are the bodies of long-dead animals. But making a fossil takes a lot of time and luck. First, an animal needs to die. Then, it must be covered in mud. The mud should dry slowly. The right steps help save the animal's shape. If it dries too fast, this can destroy the fossil. Also, nothing should touch the bones. Finally, a fossil needs to age for 10,000 years to fully form. This is why fossils are so rare. Only about one bone in a million becomes a fossil.

A plant or animal goes extinct when all of its kind dies out. Sometimes, many plants and animals go extinct at the same time. This is a mass extinction. When this happens, nature tries to bring them back. But many times, the animals and plants are gone forever. There have been several mass extinctions. Each time, the conditions changed on our planet. The climate changed, or the air changed. Sometimes, it was because of a volcano or an asteroid. This last one happened 66 million years ago. Then, all the dinosaurs died out. Now, the temperature on Earth is rising. This is because of pollution. We should be careful. We might cause the next mass extinction!

In movies, scientists bring back the dinosaurs. They find dinosaur DNA and use it to clone dinosaurs. Unfortunately, this is only fiction. Scientists cannot really do this. DNA becomes damaged over time. Dinosaurs went extinct millions of years ago. So, their DNA is too damaged to use. The thought of bringing back ancient animals is thrilling to imagine. It makes us wonder about the possibilities of science. However, we could clone other extinct animals. Their DNA is not as old, so it is less damaged. For example, the mammoth went extinct only 10,000 years ago. We might be able to bring it back. Do you want to see a mammoth? Someday, you just might!

The 15th century is known as the Age of Exploration. There were many brave explorers at the time. One of the most successful was Ferdinand Magellan. He came from Portugal. Magellan believed he could travel to India through the Americas. He left Spain with five ships and a 300-man crew. He sailed to South America. He discovered a path through South America. He called it the Straits of Magellan. Then he sailed across the Pacific Ocean. He lost two of his ships doing this. Sadly, Magellan was killed by a poison arrow in the Philippines. But his crew continued and returned home.

Most of the ocean is a mystery. We have to use powerful cameras to see what it's like. We've found mountains, canyons, and even waterfalls under the sea. But cameras cannot show us everything. The deep sea hides many secrets. Explorers are always curious about it. We have to see for ourselves. Jacques Piccard was a scientist who studied the oceans. He wanted to reach the deepest part of the ocean. So, he built a submarine. He called the place he found "Challenger Deep" because it was so hard to get to. There, he found something amazing: fish and shrimp. Nobody thought any creature could live that deep.

Roald Amundsen was an extraordinary adventurer. He found the Northwest Passage. The route connects the Atlantic Ocean to the Pacific Ocean. He discovered it in 1903. His journey was filled with challenges. In 1911, Amundsen went to Antarctica. He became the first man to reach the South Pole. He traveled with five others and eleven dogs. They traveled for 99 days in the freezing cold. Amundsen wasn't finished with his adventures. In 1926, he traveled to the Arctic. He was the first to fly over the North Pole. In 1928, he tried to rescue a lost crewmate. Sadly, Amundsen disappeared and never returned.

Valentina Tereshkova was the first woman in space. Surprisingly, she was not a pilot; she was a skydiver. She had done 126 umps before entering the space program. She trained hard and faced many challenges. She never gave up. She always dreamed of touching the stars. The program accepted her because of her special talents. At the time, astronauts had to be good skydivers. That's because they had to jump from their spaceships before landing. This was very dangerous. It was also why Valentina was the best choice. In 1963, Valentina was launched into space. She spent three days in space. She went around the Earth 48 times. After landing, she became world famous.

Oshibana is a Japanese art style. Oshibana artists use pressed flowers to create pictures. They take live flowers and press them flat. Then they dry them. A common way to dry a flower is to press it between two pieces of paper. This removes the moisture. It also keeps the petals safe. Oshibana was first practiced in 16th-century Japan. But pressed flowers have been popular for a long time. Knights pressed flowers as souvenirs. Scientists pressed flowers to study them. Give it a try! All you need is paper, a heavy book, and flowers.

Designer toys or "art toys" are collectibles. Unlike teddy bears and dolls, art toys are not for playing with. They are for viewing. People treasure these toys like fine art. They often display them in special cases. Artists make art toys. Some are famous painters. Some are comic book artists. Some are even graffiti artists. They make art toys with plastic and other more unusual materials. They make them in limited numbers. They can be very expensive. Some sell for thousands of dollars. Designer toys first appeared in the 1990s. Now there are many kinds. For example, Qees, Be@rbricks, and Dunnys. Have you ever seen one of these?

Your eyes see color, lights, and patterns. But your eyes don't make images; your brain does. Your brain uses information from your eyes to create an image. But your brain also takes shortcuts. It fills in details. These details are not always real. When this happens, a person sees an optical illusion. Optical illusions can be fascinating. They play tricks on our minds. Some illusions have been used in magic tricks for entertainment. Take the Ponzo Illusion, for example. It's a drawing of a train track. On it, there are two yellow lines. Which one looks longer? They're of equal length. The top one looks longer because your brain thinks it's further away.

Traditional animation is made with many pictures. Each picture is drawn differently. When shown quickly, these pictures appear to move. This method requires a lot of work. Every frame is carefully crafted by hand. There are other kinds of animation. Sand animation is a kind of performance art. Artists use sand to make images. They do this using a box with a light inside. This creates an image with the shadows. Sand artists perform in front of an audience. They use the sand to tell a story. The first sand artist was a student at Harvard University. She made a film in 1968. It was called Sand, or Peter and the Wolf.

Many people wake up to an alarm clock. But how did people wake up before alarm clocks were invented? They used a knocker-up. Knocker-ups were people. This job was important in the early morning. The streets were quiet as they did their rounds. Factories hired them to wake up workers. Knocker-ups were often elderly people or police officers. They would knock on people's windows. They had many tools. They often used bamboo sticks, small stones, or peashooters. In the 20th century, knocker-ups started disappearing. They lost their jobs because of alarm clocks. Alarm clocks were cheaper and more reliable. What are some other jobs that have disappeared?

What's the most dangerous job? Some people think it's logging. Over 100 loggers out of every 100,000 die in a work accident. There are many reasons for this. Loggers use dangerous tools, like chainsaws. They work with big machines. They cut down heavy trees. They also work in hard-to-reach places. They often work deep in the wilderness. So, it's difficult for an ambulance to reach a hurt logger. However, despite these dangers, many loggers are passionate about their jobs. Loggers do have rules to stay safe. But many still die every year. Some people believe we should only use machines for this work. But then many loggers will lose their jobs.

Automation means using a machine to do a job instead of a person. In the past, machines only did simple jobs. But nowadays, they can do complicated work, too. In fact, machines now assist doctors in surgeries. They even help with customer service. This worries people. They fear they'll be made unemployed. But is this true? It's complicated. Automation does replace certain jobs. But automation also creates jobs. In the past, bank workers feared ATMs would steal their jobs. But, in truth, more jobs were created. Banks employed more salespeople and accountants. What do you think? What future jobs will be made by automation?

What skills do you need for the future? Businesses believe there are four: Businesses want smart social media users. Social media is a great way to communicate. Mobile phones and computers are also good for communication. They are tools we use every day. Knowing how to use them can be a big advantage. We use them to shop and work. Businesses want people who use these technologies well. Analytics is the study of information. Businesses study what customers do. This tells them about customers' needs. Cloud computing is useful for workers. It helps them work together. It also helps businesses. They can make necessary changes faster. Do you have any of these skills.