This is my summary of the inventions I learned about in lessons one hundred twenty-six through one hundred twenty-nine. In lesson one hundred twenty-six, I studied the invention of the light switch. While there were light switches before the version we know today, they were a fire hazard. Because of the speed the circuit broke at, it was likely to cause an electrical arc to form. This would cause the switch to deteriorate faster, and could cause fires in the walls.

John Henry Holmes invented a solution to this problem in 1884, and it became known as the quick-break light switch. He worked around electrical switches all day, and noted their tendency to spark fires when people used them. The quick-break switch breaks the circuit faster than an arc can form, making them much safer than the older models. Now, light switches can safely be installed in homes and factories without fear of causing fire – think of how hard it would be to use Thomas Edison’s light bulb if there’s nothing to power it! Even though improved light switches have been invented since then, the quick-break mechanism is still used today.

In lesson one hundred twenty-seven, I learned about the invention of the skyscraper. While the skyscraper is a unique invention, note that it was only made possible due to other inventions – concrete, steel, and the elevator being a few of them. Before the skyscraper was invented, it was difficult to make tall buildings; the taller the building, the thicker the brick walls on the bottom floors.

The skyscraper was invented in 1884 by William Jenney, who was an architect in Chicago. Jenney’s inspiration came when his wife set her heavy book on the top of a birdcage. The cage held, and he wondered if he could do the same for buildings. Jenney used steel to make a sort of cage that took the majority of the building’s weight, and it worked. The invention of the skyscraper made it much more efficient to build tall structures as well as safe.

In lesson one hundred twenty-eight, I studied the invention of the dishwasher. Before the dishwasher was invented, washing dishes was a very tedious process. Some houses even had an extra room dedicated to dishwashing called the scullery, and it was a damp area and full of bacteria. This would sometimes cause families to be permanently sick, since the germs from washing dishes stayed in the air.

The automatic dishwasher was invented by Josephine Cochrane in 1886. The Cochranes often hosted dinner parties using their antique chinaware, but the servants chipped and broke them while during the washing process. Josephine got tired of it, and invented a machine that used water pressure and heat to clean the dishes. She called it the dishwasher, and it has become a very useful tool in our lives today.

Last of all, lesson one hundred twenty-nine was about the invention – or discovery, whichever way you want to look at it – of electromagnetic waves. James Clerk Maxwell predicted the existence of electromagnetic waves, which are invisible waves that carry energy throughout space without needing a particular substance to ride on.

Heinrich Hertz proved the predictions of Maxwell in 1887 using experiments. This worked probably because Maxwell’s theory was about something that might exist in the present or future, not something in the past. This is part of the reason why we can trust the experiments – they prove something that we can check to make sure it’s right. If electromagnetic waves only existed thousands of years ago, for example, we wouldn’t be able to go back and see if the experiments prove something correct. Electromagnetic waves travel at the speed of light, and can carry a signal over great distances. This quality made cell phones and television possible, as well as much of technology we use today.