Solar cells use materials, like silicon, that are a. conductive b. semi-conductive c. insulating
The effect that converts sunlight into electricity is called the a. photographic effect b. photosynthetic effect c. photovoltaic effect
Solar power is an example of a. wasteful energy b. nuclear energy c. renewable energy
Discussion/essay questions
Would you ever consider using solar panels? Why or why not?
Using renewable energy sources is one good way to fight climate change. What are some other ways? What actions do you think individuals should take? What actions do you think governments and companies should take?
Transcript
A solar panel converts sunlight into energy. It is made up of parts called solar cells, which use semi-conductive materials to create electrical currents. This happens through a process called the photovoltaic effect. When light hits a semi-conductive material, like silicon, it causes electrons to jump around. The movement of the electrons creates a current. The first solar cells were invented in 1954. However, early solar panels were not very practical. They were expensive to build, and they only converted a small percentage of sunlight into power. Today, solar panels are cheaper and more effective. A solar panel is an example of renewable energy. Solar energy is collected at solar farms, which use large arrays of panels. Some homeowners also use solar panels on their roofs to save on electricity bills and protect the environment. Researchers have even suggested using solar panels from space to power the Earth.
Entropy is a measure of a. light b. reactivity c. randomness
In physics, a “system” is a. a group of subatomic particles b. a mix of different chemicals c. any collection of objects
For one system to _______ in entropy, another system has to _________ in entropy. a. increase, decrease b. decrease, increase c. decrease, decrease
Discussion/essay questions
Some scientists believe that the universe could be part of an even bigger system of universes. Do you think it is possible that there are other universes out there? Why or why not?
Transcript
Entropy is an important concept in physics. It measures the amount of randomness in a system. A system is any collection of objects. It can mean a few molecules or the entire universe. The second law of thermodynamics states that entropy always increases. A system can only decrease in entropy if it causes another system to increase in entropy. This is because there are always more possible states of chaos than states of order. As a result, the universe will always get more random and disordered over time. For example, there are only a few ways to clean a messy room, and it takes a lot of work. However, it is easy to mess up a clean room, and there are infinitely many ways to do it. Increasing entropy is the reason that glasses shatter but never put themselves back together. It is also the reason humans get older but never younger. Because entropy always increases, we can only experience time in one direction.
Gigantism occurs a. in warm water b. in water with high salt levels c. in deep water
Deep-sea creatures have slower metabolisms because of a. the temperature of the water b. the lack of light c. the nutrients in the food
These animals grow larger because a. they eat more food b. they have more time to mature c. they need to look like predators
Discussion/essay questions
Scientists have only explored about 5% of the oceans. What else do you think they might discover in the future?
Transcript
Sea creatures that live in the depths of the ocean can sometimes grow much bigger than similar creatures that prefer shallow waters. This is a phenomenon called deep-sea gigantism. A well-known example of deep-sea gigantism is the colossal squid, which can grow up to 14 metres long. There are several theories about the causes of deep-sea gigantism. It is believed that the colder temperatures at the bottom of the ocean can slow an animal’s metabolism. This is important for the survival of deep-sea creatures. Food can be hard to find in the cold, dark water, which means that these creatures have to conserve their energy. With such slow metabolisms, they take a long time to mature. This allows them to continue growing.
Nuclear fusion is a type of reaction that turns one chemical element into another. The Sun and other use nuclear fusion as a form of power. In high enough , the nucleus of an atom can be separated from its electrons. The heat causes the nucleus to move very quickly. When two nuclei come close enough to each other, they fuse, forming a larger nucleus. This method allows stars to convert hydrogen atoms into helium atoms, and even more atoms after that. Nuclear fusion is a difficult to replicate on Earth, because it requires a lot of heat and pressure. However, many research groups around the world hope to find a way to use it as an source.
Comprehension questions
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Discussion/essay questions
Scientists are interested in nuclear fusion because it would be a clean and powerful energy source. Unlike the type of nuclear power we use today, nuclear fusion would not create dangerous waste. Can you think of any potential disadvantages to this type of energy?
Transcript
Nuclear fusion is a type of reaction that turns one chemical element into another. The Sun and other stars use nuclear fusion as a form of power. In high enough temperatures, the nucleus of an atom can be separated from its electrons. The heat causes the nucleus to move very quickly. When two nuclei come close enough to each other, they fuse, forming a larger nucleus. This method allows stars to convert hydrogen atoms into helium atoms, and even more complex atoms after that. Nuclear fusion is a difficult process to replicate on Earth, because it requires a lot of heat and pressure. However, many research groups around the world hope to find a way to use it as an energy source.
In 1928, British physicist Paul Dirac the existence of antimatter. His theory was that every type of subatomic particle had an antiparticle. He believed that an antiparticle would be almost identical to a normal particle, only with an electrical charge. This theory was proven two years later, when American physicist Carl David Anderson discovered a positively-charged electron, later named the “positron”. Today, physicists know that our is made up of both matter and antimatter. They have even successfully created antimatter atoms. However, antimatter is still one of the greatest in the universe. Scientific theory states that the Big Bang should have created equal amounts of matter and antimatter. The problem with this idea is the fact that matter and antimatter instantly destroy each other when they come into contact. This means that if the Big Bang had as much antimatter as it did matter, the universe would not exist today.
Comprehension questions
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Discussion/essay questions
For years, scientists have debated the reason why our universe has more matter than antimatter. Some scientists have even suggested the idea that the Big Bang created another, parallel universe, made up mostly of antimatter. However, there isn’t a lot of evidence for this. Do you think scientists will ever know the answer to this question, or are there just some things about the universe we will never understand?
Transcript
In 1928, British physicist Paul Dirac predicted the existence of antimatter. His theory was that every type of subatomic particle had an antiparticle. He believed that an antiparticle would be almost identical to a normal particle, only with an opposite electrical charge. This theory was proven two years later, when American physicist Carl David Anderson discovered a positively-charged electron, later named the “positron”. Today, physicists know that our universe contains both matter and antimatter. They have even successfully created antimatter atoms. However, antimatter is still one of the greatest mysteries in the universe. Scientific theory states that the Big Bang should have created equal amounts of matter and antimatter. The problem with this idea is the fact that matter and antimatter instantly destroy each other when they come into contact. This means that if the Big Bang had created as much antimatter as it did matter, the universe would not exist today.
