Energy is stored in chemical compounds. This energy is called chemical energy. Chemical energy is a form of potential energy. When bonds between atoms are broken, energy is released. The wood in fireplaces has chemical energy. The energy is released as heat and light when the wood burns. Most living things get their energy from food. When food molecules are broken down, the energy is released. It may then be used to do work, like playing ball or studying science. If you have ever heard, "Eat a good breakfast", thats why. You need energy to do things during the day. To do those things you need energy. You get your energy from the food you eat. That energy is stored in your body until you need it. How did you get to school today? If you walked, you used chemical energy from the food you ate. What if you rode the bus or were driven in a car? Where did that energy come from?

Question: "What is released when chemical compounds break down?"

Response: "Solar energy"

A: no

If you have a mass of 50 kg on Earth, what is your weight in newtons? An object with more mass is pulled by gravity with greater force. Mass and weight are closely related. However, the weight of an object can change if the force of gravity changes. On Earth, the force of gravity is the same everywhere. So how does the force of gravity change? It doesnt if you stay on Earth. What if we travel to another planet or moon in our solar system? Look at the photo of astronaut Edwin E. Aldrin Jr. taken by fellow astronaut Neil Armstrong in the Figure. They were the first humans to walk on the moon. An astronaut weighs less on the moon than he would on Earth. This is because the moons gravity is weaker than Earths. The astronauts mass, on the other hand, did not change. He still contained the same amount of matter on the moon as he did on Earth. If the astronaut weighed 175 pounds on Earth, he would have weighed only 29 pounds on the moon. If his mass on Earth was 80 kg, what would his mass have been on the moon? [Figure 3]

Question: "Why would a person's weight not change on Earth but it would on the moon?"

Response: "Because the mass changes on Moon but does not change on Earth"

A: no

Josie started planning her new garden in the winter. She chose flowers and vegetables that could grow in her area. She looked through the seed magazines. She ordered the tastiest kind of each vegetable and the prettiest kind of each flower. She talked to a friend about her plans. It seemed like the snow would never melt. But Josie didn't have to wait for spring to get started. Six weeks before the last frost, Josie planted seeds indoors. The tiny seedlings pushed up through the soil and began to grow. Finally spring arrived. Each day, Josie moved the seedlings outside for a few hours so they could get used to the cooler temperatures. Josie worked in her garden, digging the soil. She added a special growing mix from the garden store to make the soil better. When everything was ready, she removed the seedlings from their trays and planted them in her garden. The warm sun and rich soil helped her vegetables and flowers grow.

Question: "How did Josie get her vegetables to grow so quickly?"

Response: "Special growing mix"

A:
yes