Score
Title
616
How To Search ELI5: A Quick Reminder About Rule 7
3274
ELI5: How is magnesium, an easily flammable metal used in flares, used to make products such as car parts and computer casings?
9901
ELI5: Why do LED lights look jittery or like they're strobing when you look at them quickly?
109
ELI5: What is the Speed of a Photon as it Gets Reflected by a Mirror?
77
ELI5: What is the difference between a tort and a crime?
9
ELI5:If you put water into an unbreakable container and froze it, what would happen?
6
ELI5: Does a person age slower living on the equator than the arctic circle due to traveling faster in the same amount of time?
6
ELI5: Why do lines appear in the picture when you photograph a computer screen?
5
ELI5: If one company buys out another company for a monetary fee, wouldn’t the money go back to the parent company, therefore the parent company essentially gained capital for free since they own the other company? How does that work?
4
ELI5: How the speed of light is constant in all reference frames
8
ELI5: Plants vs Fungi
3
ELI5: What is an RSS Feed?
3
ELI5:Why would the government produce a record of all the CIA's wrong doing?
5
ELI5: Why does freshly squeezed orange juice taste so different from orange juice in a carton?
4
ELI5: Why is the standard deviation of the sampling distribution less than the standard deviation of the population?
3
ELI5: how can Washington Lake (freshwater) exist on Teraina (middle of the Pacific Ocean)?
2
ELI5: Why does it become nearly impossible to hold your bladder when you are near to the bathroom?
4
ELI5: Why didn’t any astronomers see the meteor that went past Michigan?
3
ELI5: what is a bond investment in relation to a Roth IRA?
2
ELI5:How come a person's signature is needed when paying with a credit card if the staff doesn't check it?
5
ELI5: Why is sound measured in decibels? Is it logarithmic?
3
ELI5: zipped files
1
ELI5: How can projector produce a black image.
1
ELI5: Why do conduction and valence bands occur?
2
ELI5: Why does liquid bubble when it boils?
1
ELI5: Why do you get cramps when you drink water really fast and exercise/run?
6
ELI5:What is the difference between Term life and Whole life insurance?
2
ELI5: Bank of Canada Interest Rate: Why do they raise it, why is it good to raise it (and who for), and why can’t they leave it at 0%?
1
ELI5: Why is it more difficult to wake up when its raining/cloudy outside?
3
ELI5: Why is it that when we try to remember something in the past, it sometimes takes a minute to actually recollect it? What is our brain doing during that time?
1
ELI5: How do the etymologies of the words 'deductive'-, 'inductive'- and 'abductive'- reasoning fit in with their definitions?
0
ELI5: How do guitar pickups avoid picking up other vibrations and background noise?
1
ELI5: Linking cars together like a train to go up a hill collectively more effective than going by your car’s power singularly
1
ELI5: The difference between square rooting and simplified square rooting?
3
ELI5: Why do cars slightly move up when your foot isn’t touching the gas pedal?
3
ELI5: Why is our bodies reacting like it is to drugs like heroin.
3
ELI5: How do I calculate these probability situations if my math skills end around algebra?
7
ELI5:Why do certain colors of lights have a second, differently colored ring around the source?
2
ELI5: How do Bionic Ears work?
1
ELI5: What is an Exchange-Traded Fund?
1
ELI5: Why is deer meat described as “gamey”? What does “gamey” mean?
587 kouhoutek With great difficulty over the better part of a century. The Great Trigonometrical Survey of India started from the ocean in 1802, and 100 feet at a time, took measurements and did a bunch of math, and worked there way across the sub-continent to the Himalayas, completing in 1871. It was a great scientific achievement, lead during some of its more important years by George Everest, who received a knighthood for his efforts. The basic technique is fairly simple. You start with two sticks at sea level, a decent distance apart, and measure their exact longitude and latitude. Then you put a third stick some distance away and inland, making a triangle. Based on the distance between the first two sticks and the angles they form with the third stick, you can compute the third stick's exact position and elevation. Once all that is done, you repeat, planting a stick further inland and drawing a new triangle. The Great Survey did this with better instruments, better technique, and on a greater scale than had ever been done before.
80 CantTake_MySky Also, math and triangulation. Trigonometry has been around a long long time. See, with just one side of a triangle and the angle between it and another side, you can figure out the missing side. So if you make the triangle such that once side is easy to measure, and then you use a protractor and your vision to determine the angle, you can math the height.
37 ak_kitaq A field of study called geodetics used instruments called Theodolites. Sometimes they were called diopters. The theodolites almost look like telescopes but with a lot of rulers on it so you can determine which direction the telescopes are pointing, up-and-down and side-to-side. Using the measurements from the rulers on the theodolite, you can use math called Trigonometry to tell you how far away something else is. In the case of Chomolungma (Mt Everest), the British started from the ocean in India and measured all the way across the country until they could see the mountain. After getting their measurements, they did the math and found out how tall they thought the mountain was.
1615 PrimeMinisterEdBalls One way is by making a cup of tea. Water boils at 100°C only at sea level. The temperature at which water boils varies based on air pressure. For every 1000 metres, the boiling point drops by about 5 degrees. Thus, with a kettle and a thermometer you can estimate altitude.
14 billbixbyakahulk Trigonometry. In high school we visited an amusement park. By being a known distance from the base of the top of the roller coaster hill (length and angle (90 degrees) of one side of the triangle) and then calculating the angle to the top of the structure using a sighting scope, we could calculate the height. [This pic](https://image.slidesharecdn.com/heightanddistances-120108094402-phpapp01/95/height-and-distances-12-728.jpg?cb=1326016394) sums it up.
91 [deleted] [removed]
7 WarConsigliere They often didn't. I can't find the citation easily, but in the late 1990s/early 2000s, a very large number of Australian mountains and waterfalls had their heights revised after someone realised that there were a stupidly large number of them that were listed as having a height of 305 metres. Some went up, most went down - a couple by more than half. It turned out that the official height figures were often the estimates of the original explorer/surveyor and no-one had been arsed to actually measure them, especially because they weren't a suspiciously round number. Of course, the reason that they weren't a round number was because during metricisation in the 1970s a height of 1,000 feet had been converted to 305 metres, but that was before heights were recorded on computers and easily checked against each other.
588 0 kouhoutek With great difficulty over the better part of a century. The Great Trigonometrical Survey of India started from the ocean in 1802, and 100 feet at a time, took measurements and did a bunch of math, and worked there way across the sub-continent to the Himalayas, completing in 1871. It was a great scientific achievement, lead during some of its more important years by George Everest, who received a knighthood for his efforts. The basic technique is fairly simple. You start with two sticks at sea level, a decent distance apart, and measure their exact longitude and latitude. Then you put a third stick some distance away and inland, making a triangle. Based on the distance between the first two sticks and the angles they form with the third stick, you can compute the third stick's exact position and elevation. Once all that is done, you repeat, planting a stick further inland and drawing a new triangle. The Great Survey did this with better instruments, better technique, and on a greater scale than had ever been done before.
79 0 CantTake_MySky Also, math and triangulation. Trigonometry has been around a long long time. See, with just one side of a triangle and the angle between it and another side, you can figure out the missing side. So if you make the triangle such that once side is easy to measure, and then you use a protractor and your vision to determine the angle, you can math the height.
37 0 ak_kitaq A field of study called geodetics used instruments called Theodolites. Sometimes they were called diopters. The theodolites almost look like telescopes but with a lot of rulers on it so you can determine which direction the telescopes are pointing, up-and-down and side-to-side. Using the measurements from the rulers on the theodolite, you can use math called Trigonometry to tell you how far away something else is. In the case of Chomolungma (Mt Everest), the British started from the ocean in India and measured all the way across the country until they could see the mountain. After getting their measurements, they did the math and found out how tall they thought the mountain was.
1616 0 PrimeMinisterEdBalls One way is by making a cup of tea. Water boils at 100°C only at sea level. The temperature at which water boils varies based on air pressure. For every 1000 metres, the boiling point drops by about 5 degrees. Thus, with a kettle and a thermometer you can estimate altitude.
14 0 billbixbyakahulk Trigonometry. In high school we visited an amusement park. By being a known distance from the base of the top of the roller coaster hill (length and angle (90 degrees) of one side of the triangle) and then calculating the angle to the top of the structure using a sighting scope, we could calculate the height. [This pic](https://image.slidesharecdn.com/heightanddistances-120108094402-phpapp01/95/height-and-distances-12-728.jpg?cb=1326016394) sums it up.
91 0 [deleted] [removed]
7 0 WarConsigliere They often didn't. I can't find the citation easily, but in the late 1990s/early 2000s, a very large number of Australian mountains and waterfalls had their heights revised after someone realised that there were a stupidly large number of them that were listed as having a height of 305 metres. Some went up, most went down - a couple by more than half. It turned out that the official height figures were often the estimates of the original explorer/surveyor and no-one had been arsed to actually measure them, especially because they weren't a suspiciously round number. Of course, the reason that they weren't a round number was because during metricisation in the 1970s a height of 1,000 feet had been converted to 305 metres, but that was before heights were recorded on computers and easily checked against each other.