![]() These sizeable differences in lifetime earnings put the costs of college study in realistic perspective. According to the Census Bureau, over an adult's working life, high school graduates earn an average of $1.2 million associate’s degree holders earn about $1.6 million and bachelor’s degree holders earn about $2.1 million (Day and Newburger, 2002). Though the earnings differential between college and high school graduates varies over time, college graduates, on average, earn more than high school graduates. There is considerable support for the notion that the rate of return on investment in higher education is high enough to warrant the financial burden associated with pursuing a college degree. In order to determine whether higher education is worth the investment, it is useful to examine what is known about the value of higher education and the rates of return on investment to both the individual and to society. The risk is especially large for low- income families who have a difficult time making ends meet without the additional burden of college tuition and fees. Many wonder whether the high cost of tuition, the opportunity cost of choosing college over full-time employment, and the accumulation of thousands of dollars of debt is, in the long run, worth the investment. They use special electronic sensors that can be raised above water.The escalating cost of higher education is causing many to question the value of continuing education beyond high school. Some newer submarines don’t even have periscopes. Some use complex prisms that are much sturdier. Today, submarine periscopes use all sorts of new technology to replace simple mirrors. Sir Howard Grubb made major improvements to the invention during World War I. Later, Simon Lake added the device to the submarine in 1902. The first naval periscope was invented by Hippolyte Marie-Davy in 1854. It allowed spectators to see over other people in a crowd at religious festivals. For example, Johann Gutenberg created a periscope-like device in the 1430s. Who invented the periscope? It’s existed in different forms for a long time. They make the reflected images bigger so that you can see them easier. For that reason, their periscopes have special magnifying lenses. Isn’t it cool how a periscope uses simple scientific principles to let you see around corners or even above water from a submarine? Submarines often can’t come all the way to the surface of the water. The light then hits the bottom mirror and bounces into your eyes. That light enters the periscope and bounces off the top mirror. ![]() For example, light bounces off the object you’re looking at with the periscope. The mirrors are attached so that they are parallel to each other at a 45-degree angle.Īrranged in this way, the mirrors bounce reflections of light between them. The main part of a periscope is a long tube that has a mirror at each end. Periscopes are similar to telescopes in how they’re built and how they work. They’re also used in armored vehicles, such as tanks, to see outside when all the vehicle’s openings are shut tight. In World War I, they helped soldiers see beyond the tops of trenches. Periscopes can be used in many ways beyond seeing above water from a submarine. Where does the word “periscope” come from? It’s a combination of the Greek words “peri” and “scopus,” which mean “around” and “look.” It allows people inside the submarine to see what’s going on above water. Instead, submarines have a special device called a periscope. But how would you do that in a submarine? It’s not like they have sunroofs you could open to see what’s happening up above. If you had a submarine, where would you go? Searching for sharks? Exploring the depths of the Mariana Trench or the mysterious Bermuda Triangle? The depths of the sea contain many unexplored frontiers, so your adventures could be never-ending!Įvery once in a while, you’d probably want to come up to the surface to see what’s going on above water. You’d need a lot of water to be able to have fun with it. How cool would it be to own your own submarine? Of course, submarines are very expensive.
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