The idea that Earth is a magnet is far from new. It was first proposed in 1600 by a British physician named William Gilbert. Knowing it acts like a magnet is one thing. Knowing why it acts like a magnet is more difficult. In fact, finding out why is a fairly recent discovery. To find out why required new technology. It was the seismograph that made it possible to learn why the Earth acted like a magnet. Seismograph are used to study earthquakes. By studying earthquake waves they were able to learn about Earths interior. They discovered that Earth has an inner and outer core. The outer core consists of liquid metals, mainly iron and nickel. Scientists think that Earths magnetic field is generated here. It is caused by the motion of this liquid metal. The liquid metal moves as Earth spins on its axis.

Question: "What did William Gilbert first speculate in 1600?"

Response: "That Earth has magnetic field"

A: yes

Have you ever seen an egg? Some animals do not have live births. Instead, they lay eggs. The eggs contain the embryo. The embryo matures in the egg. With time, it will hatch. Some animals hatch and do not need care from their parents. They are ready to live on their own. Other animals will still need the care of their parents. Sea turtles break out of their shells. They immediately walk to the ocean. They do this with no help from an adult. Birds stay in the nest for many weeks. They are cared for by their parents. They leave the nest when they are strong enough to fly. Some animals give birth to live offspring. Animals like horses, cows, and whales give live birth. Their offspring are born looking like mini adults.

Question: "What is an example of an animal that gives live birth?"

Response: "Whales"

A: yes

One day, Phoebe woke up and found that her house had been broken into. Her front door was wide open. She went into the living room and saw that her television set and stereo were missing. She checked the kitchen, but didn't find anything missing there except for a clock. Then she saw that her purse had been stolen too. She called the police to report what had happened. The police officer told her that there had been a lot of cases like this in her neighborhood lately, and they were looking for the criminals. Phoebe went into her bedroom and started to cry. She had no money to buy a new television set or stereo. She was scared that the robbers might try to break into her house again. She called her friend Mary and asked her what to do. Mary told Phoebe to change her front door lock right away. She said she knew a detective who could try to find the robber who had broken into her house. Phoebe thanked Mary, and said she felt safe knowing that there was someone who could help her catch the robber so he wouldn't do it again.

Question: "Why did Phoebe have no money to buy a new television and radio?"

Response: "Her purse was stolen"

A:
yes