As a teenager, Einstein wondered what would happen if a human could chase a. a beam of light b. a train c. a clock
Einstein’s 1905 theory is called a. general relativity b. special relativity c. universal relativity
The speed of light is a. constant b. variable c. relative
Discussion/essay questions
Most scientists think that time travel to the past is probably not possible. However, time dilation means that time travel to the future would be possible if we could move very fast. What would you do if you could time travel? Do you think it would be more interesting to travel to the past or the future?
Transcript
When Albert Einstein was a teenager, he wondered what would happen if a human could run fast enough to chase a beam of light. This thought experiment led to his 1905 theory of special relativity. Einstein’s theory showed that time was not universal. People could experience time differently if they were moving very fast. This effect is called time dilation. Einstein used a few scientific laws to support his theory. The first was that speed is relative. Two trains travelling at the same speed in the same direction stand still relative to each other. However, experiments before Einstein had already proved that the speed of light is always 300,000 kilometres per second. This is true no matter how fast the observer moves. Even if a person could chase a beam of light, the light would always outrun them by the same speed. Einstein realized that because the speed of light was constant, another variable had to change. This variable was time. Since Einstein published his theory, experiments have shown that clocks run slower at high speeds.
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.
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.
