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.
The escape velocity is a. the maximum mass of an object travelling into space b. the minimum mass of an object to be a strong source of gravity c. the minimum constant speed of an object travelling into space
The escape velocity of Earth is about a. 9.8 km/s b. 11.2 km/s c. 40,000 km/s
It would be easiest to launch an object from a. Earth b. the Moon c. a black hole
Discussion/essay questions
Reaching outer space was an important achievement in human history. What kinds of space exploration do you think will be possible in the future?
Transcript
Every source of gravity in the universe has an escape velocity. This is the minimum constant speed that an object has to travel to fully escape from a planet or star and enter outer space. For an object of any mass to be launched into space from Earth, it must be travelling at about 11.2 km/s, or 40,000 km/h. To determine escape velocity, scientists need to know the mass and radius of the source of gravity. Escape velocity increases for planets and stars with more mass. It would be easier to launch something from the Moon than from Earth. For a black hole, which has infinite density, the escape velocity is greater than the speed of light. This is why nothing can possibly escape from its gravity.
The purpose of Schrödinger’s thought experiment was a. to study radioactive substances b. to demonstrate the durability of cats c. to show the flaws in a scientific theory
In the experiment, the poison would be activated by a. the movements of the cat b. the locking of the box c. the decaying of the substance
According to the theory, the experiment would cause a. the cat to die several times until someone opened the box b. the cat to stay alive until someone opened the box c. the cat to be both alive and dead until someone opened the box
Discussion/essay questions
Why do you think it is so easy to be misinformed about science? Do you think there is a solution to this?
Do you think it is important for the general population to be educated about scientific topics? Why or why not?
Transcript
“Schrödinger’s cat” is a thought experiment created by Austrian physicist Erwin Schrödinger. The purpose of the experiment was to show the flaws in a scientific theory suggesting that particles can only definitively change if someone is observing them. In Schrödinger’s example, a cat is locked in a box with a radioactive substance and a container of poison. If the substance decays, it activates the poison and kills the cat. Schrödinger argued that if the decaying of the substance could not happen until someone observed it, then the cat would be both alive and dead until someone opened the box. Although Schrödinger’s goal was to show how strange this idea was, many people misinterpreted him. This misunderstanding has caused some people to believe that it is possible for a cat to be both alive and dead.
Stephen Hawking once had a party for time travellers. He didn’t send the invitations out until the day after the party, so that only people from the future could show up. It was an experiment that was meant to show that time travel to the past was unlikely to be possible. Do you think that time travel could ever be possible? Why or why not?
Transcript
Stephen Hawking was an English physicist. He was born in 1942 in Oxford, England. Growing up, Hawking was always very interested in math and science, and at age 17, he decided to pursue a physics degree. However, at age 21, Hawking was diagnosed with ALS, a serious condition that weakens nerves and muscles. His doctor didn’t expect him to live more than two years after his diagnosis, but Hawking was determined to get his degree. He achieved his goal, and he is now well-known for his research on black holes. Throughout his life, he also published several books about the universe. His most famous book, titled A Brief History of Time, was written to help ordinary people understand complex scientific concepts. Hawking lived much longer than expected, but his condition worsened as his life went on. Eventually, he had to use a wheelchair to move around, and a speech synthesizer to communicate. Hawking died at the age of 76, after living a full and accomplished life.
In 1975, a physics professor named Jack H. Hetherington wrote a paper about atomic behaviour. He was planning to submit this paper to a well-known scientific journal called the Physical Review Letters. However, when he was proofreading his work, he realized that he had unintentionally used the word “we” when writing about himself. Although this was a small , it was very problematic. The Physical Review Letters had a rule against the use of the word “we” unless the paper had multiple authors. Hetherington had written his entire paper on a typewriter, and he didn’t want to retype it all just to fix his error. Instead, he simply to credit another author. The author he chose was his cat, Chester. He changed Chester’s name to Felis Domesticus Chester Willard, shortened to F. D. C. Willard, to make it more . Hetherington’s plan worked, and his paper was published. Eventually, he admitted that the co-author was a cat, and even had Chester copies of the paper by making ink paw prints.
Comprehension questions
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Discussion/essay questions
Hetherington’s paper is now well-known, and has been quoted by many other researchers. Do you think that his paper would have been as successful if he hadn’t had a funny story to go with it?
Transcript
In 1975, a physics professor named Jack H. Hetherington wrote a research paper about atomic behaviour. He was planning to submit this paper to a well-known scientific journal called the Physical Review Letters. However, when he was proofreading his work, he realized that he had unintentionally used the word “we” when writing about himself. Although this was a small mistake, it was very problematic. The Physical Review Lettershad a rule against the use of the word “we” unless the paper had multiple authors. Hetherington had written his entire paper on a typewriter, and he didn’t want to retype it all just to fix his error. Instead, he simply decided to credit another author. The author he chose was his cat, Chester. He changed Chester’s name to Felis Domesticus Chester Willard, shortened to F. D. C. Willard, to make it more believable. Hetherington’s plan worked, and his paper was published. Eventually, he admitted that the co-author was a cat, and even had Chester sign copies of the paper by making ink paw prints.
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.
While Marie Curie’s research did help scientists develop cancer treatments, her research was also important for the invention of the atomic bomb during World War II. The atomic bomb is still a controversial subject because of the amount of deaths it caused. Do you think Curie’s discoveries had a positive impact on the world, or a negative one?
Transcript
Marie Curie was a Polish-born French physicist, known for her research of radioactive chemicals. She was born in Warsaw, Poland in 1867, the youngest of five children in her family. Growing up, Curie was smart and curious, and dreamed of getting a university degree. However, the University of Warsaw only admitted male students at the time. In order to get her degree, Curie moved to Paris. She studied physics at Sorbonne University, and later received another degree in math. After her education, Curie went on to become a scientist. While working with a mineral known as pitchblende, Curie discovered a new chemical property, which we now know as radioactivity. She also discovered two new elements, which she called polonium and radium. Because of these scientific discoveries, Curie became the first person to ever win two Nobel Prizes. Curie died in 1934 from an illness caused by her exposure to radiation. However, her research has helped modern scientists develop treatments for cancer, and she is still seen as one of the greatest scientists of all time.
Some people wanted to use Einstein’s discoveries to develop weapons, such as the atomic bomb. What is your opinion on the use of new scientific discoveries to build stronger weapons?
Transcript
Albert Einstein was one of the most influential scientists of the 20th century. He was born in Germany in 1879, and he began attending school in 1885. As Einstein got older, he became fascinated with the nature of light. He wrote his first scientific paper at the age of 16, and later went on to study physics at a university in Switzerland. In 1905, Einstein published four scientific papers. The papers introduced his theory of special relativity, which allowed scientists to better understand the connection between time and space. Einstein won the Nobel Prize in 1921 for his achievements. In the 1930s, however, Einstein became a target of the Nazi Party of Germany. He moved to the U.S. to protect himself, and continued to work as a physicist. Einstein died in 1955, but his brain is still kept in the Princeton University Medical Center. Scientists still study it today.
