The company that offered a cash reward for an ivory replacement made a. pianos b. billiard balls c. combs
Hyatt called his material a. cellulose b. celluloid c. cellular
The first truly synthetic plastic was made in a. 1863 b. 1907 c. 1960
Discussion/essay questions
Recycling is one way people try to reduce plastic waste. However, only a small percentage of plastics are actually recycled. What can people do to use less plastic? Do you think governments should ban certain plastics? Why or why not?
Transcript
Historically, items like combs, billiard balls, and piano keys were made of ivory. This was expensive, and many people became concerned about the elephant population. In 1863, a billiards company in New York offered a cash reward for a material to replace ivory. In response, an American inventor named John Wesley Hyatt created a plastic material by mixing and heating wood fibres. He called this material celluloid. Celluloid originally seemed like a solution to an environmental problem. When people around the world began to use electricity, the demand for plastics grew. Electrical wires needed insulators. In 1907, a Belgian-American chemist named Leo Baekeland used man-made chemicals to create the first truly synthetic plastic. Plastic manufacturing increased during and after both world wars. Scientists discovered the environmental impact of plastics in the 1960s, when they began to notice plastic waste in the ocean.
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.
*Correction: Tesla was actually born in the village of Smiljan, formerly in the Austrian Empire and now in Croatia
Comprehension questions
See answers below
Tesla was born in the a. 19th century b. 20th century c. 21st century
In 1884, Tesla moved to New York to work for a. George Westinghouse b. Thomas Edison c. Alexander Graham Bell
The motor that Tesla invented used a. alternating current (AC) b. direct current (DC) c. high-voltage direct current (HVDC)
Discussion/essay questions
Today, Tesla is a very well-known inventor. But for years, his work was not widely acknowledged. Do you know any other people from history who were not originally recognized for their accomplishments? Why do you think this happens?
Transcript
Nikola Tesla was a Serbian-American inventor. He was born in Austria* in 1856. In 1884, Tesla moved to New York and began working for Thomas Edison. Tesla helped Edison improve his electrical motors, but he eventually left the company after an alleged dispute about payment. Later, Tesla invented an electrical motor that ran on alternating current, or AC. This was different from Edison’s direct current motors, where electricity flowed in only one direction. An inventor and businessman named George Westinghouse funded and promoted Tesla’s project, and eventually AC made it possible to send electricity over long distances. Although Tesla was a brilliant inventor, he struggled with mental illness and financial difficulties throughout his life. As he grew older, he began to mention more ominous inventions, such as a “death ray.” The FBI investigated his possessions after his death, but found nothing dangerous.
*Correction: Tesla was actually born in the village of Smiljan, formerly in the Austrian Empire and now in Croatia
