This is my summary of the inventions I learned about in lessons one hundred fifty-six through one hundred fifty-nine.

In lesson one hundred fifty-six, I studied the invention of the polio vaccine. Before a vaccine against it was invented, polio disease was the most feared thing in America next to an atomic bomb. Polio permanently crippled most children and adults who contracted it, and it even killed some.

The polio vaccine was invented in 1955 by Jonas Salk. He originally wanted to become a lawyer, but he ended up studying to be a medical doctor. Salk wanted to do medical research to help people, so when the March of Dimes offered him money to find a way to fight polio, he consented. After much research that many people called repetitive and boring, Salk discovered a solution to polio disease, and the polio vaccine was invented. Today, we no longer fear the effects of polio disease because of this. A case of it is rare, and there is much less likelihood of it spreading.

In lesson one hundred fifty-seven, I learned about the invention of the intermodal container. Before it’s invention, shipping things across the country was difficult and labor intensive – it took days to load and unload shipments. It was also easy for people to steal.

The intermodal container was invented by Malcolm McLean in 1955 as a solution to this problem. McLean had a trucking company, and he figured it would be faster and cheaper to ship his products by boat, so he built large containers that would be easier to load and unload on all forms of transportation. This was the intermodal container, and it made the loading process much more efficient and cut the amount of time it took in half.

In lesson one hundred fifty-eight, I learned about the invention of the integrated circuit. Before the integrated circuit, vacuum tubes were used in electronics. However, they were getting too big as computers got smaller. As electronics began getting more powerful, it took just too many vacuum tubes to power them efficiently. The transistor was better, but it was still simply too big.

The integrated circuit was invented by Jack Kilby and Robert Noyce in 1959, and it was small enough to be efficient in electronics. The integrated circuit consists of a small piece of silicon with an electronic circuit etched into it using a process similar to blueprinting.

Last of all, lesson one hundred fifty-nine was about the invention of the laser. Charles Townes patented the laser in 1958. Lasers are made up of small cylinders with a specific material in it. An energy source is used to put energy into the material, and it produces light. Mirrors are placed on either end of the cylinder, and they reflect the light back and forth to make it stronger and more concentrated. The concentrated beam of light is then let out of a small hole in one mirror, and that’s the laser beam.

Lasers can be used as tools, such as to correct our vision. I personally think it might be cool to develop a laser that can be used as a precision tool for art. Since lasers are very precise and accurate, that might be useful, assuming small enough lasers with balanced power could be built.