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.
Nuclear fission was discovered in a. 1938 b. 1942 c. 1945
The lead scientist on the Manhattan Project was a. Albert Einstein b. J. Robert Oppenheimer c. Leo Szilard
70 Manhattan Project scientists signed a petition to convince the US government a. that dropping the bombs on Japan was the only way to end the war b. to end all research on the bombs and never use them c. not to drop the bombs without warning Japan first
Discussion/essay questions
How do you think the world would be different if the US hadn’t started the Manhattan Project? Do you think another country would have built and used an atomic bomb? Why or why not?
Is scientific progress always a good thing? Why or why not? How can scientists be responsible when inventing new technology?
Transcript
The Manhattan Project was a secret American project during World War II. The goal was to build an atomic bomb. Refugee scientists from Nazi Germany, including Albert Einstein, convinced the US government to begin the project after the discovery of nuclear fission in 1938. Einstein and his peers feared that the Nazis would use this discovery to build their own atomic bombs. The Manhattan Project began in 1942. The lead scientist was J. Robert Oppenheimer, who is now known as the “father of the atomic bomb.” The first successful atomic bomb test was in July of 1945. Soon after, 70 scientists who worked on the project signed a petition to convince the government not to use the bomb without warning. However, the petition never reached the president. The US dropped atomic bombs on the Japanese towns of Hiroshima and Nagasaki in August of 1945, killing close to 200,000 people. It is still one of the most controversial military acts in history.
Einstein’s theory of special relativity states that a. it is impossible for something to travel faster than light b. light travels at an accelerating speed c. the light from stars reaches Earth almost instantly
A light-year is a measure of a. time b. distance c. energy
The closest star to the Sun is about a. 4.25 light-years away b. 299 light-years away c. 1000 light-years away
Discussion/essay questions
Einstein’s theory of special relativity also states that speed can change the way we experience time. Do you think time travel will ever be possible? Why or why not?
Transcript
Einstein’s theory of special relativity states that it is impossible for anything to travel faster than light. In a vacuum, light travels at a constant speed of 299,792,458 metres per second. Scientists use the speed of light to measure distances between stars in space. A light-year is a unit that represents the distance that light can travel in a year. Even the closest stars and exoplanets are removed from our solar system by several light-years. Proxima Centauri, the closest star to the Sun, is about 4.25 light-years away. Some visible stars are thousands of light-years away. This means that the night sky is an image of the past. In fact, it is possible that some of the stars we can see no longer exist.
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.
