Transcript
Module 3.1 - Discrete Information
0:00 - In this video we're going to discuss discreet information and I’m going to contrast discreet information also known as digital information with continuous information also known as analog information. To explore discreet information, we're going to look at a little story of an orange person and a blue person out on a sunny day the orange person asked Blue person what is the temperature. The blue person replies about 22 degrees Celsius. Perhaps the blue person has a fancy app on their phone and they look at their app and say oh it's 22.3 degrees Celsius, but it's very unlikely that the blue person would say all its 22.3 175 78 321 degrees Celsius. This happen in real world you would probably be very suspicious of that blue person however that might be a more accurate reflection of what the real temperature is that is because temperature in the real world is a continuous phenomenon. Let's think of a continuous system like a mathematician consider the number of numbers that exist between 22 and 23.
1:00 - Well you might start off and say 22.5, 22.1, but as you realize you could answer 22. all one between 22 and 22.1 and then you can answer 22.013. So it turns out there's actually an infinite number of values that exists between 22 and 23 the number system we use is completely continuous. If you give me any two numbers I can find a number that exists between those two numbers and that exists for any
number in our numbering system so temperature is like numbers in that way there's an infinite precision that we could use to determine what the temperature is. If you have an old-school mercury thermometer if you can zoom in at the microscopic level, you could actually measure at great resolution what the actual temperature is. Now full disclosure for all the quantum physicists out there, temperature may not be continuous at the quantum level but that is way beyond the scope of this course so on the Left we have an old-school mercury thermometer which is…
2:00 - ... a continuous device on the right we have a digital thermometer which is what you're probably more used to. Using the mercury thermometer is continuous whereas the digital thermometer is discreet. So what do you mean by discrete? The digital thermometer might for example jump from 22.2 degrees to 22.3 degrees there's no in-between. Earlier I mentioned that numbers there's an infinite number of numbers between any two numbers but on a digital thermometer you won't have that you'll never have 22.25 degrees it's either going to go 22.2 or 22.3, that's what we mean by discrete, is only specific values that the thermometer can display; it’s not continuous now of course you can get a fancier. Digital thermometer with more precision but regardless of what the precision is it still going to be discreet. When we see a digital device whether it's a digital thermometer or digital camera what it really means is that it can only measure things in discrete levels it is not continuous so when you see the word digital referring to a device it doesn't
3:00 - necessarily mean it's electronic or use a computer what it really means is that it measures discreet phenomenon similarly when you see an analog device it means it's continuous discrete and continuous or opposites just as digital and analog are opposites the word. Digital itself comes from the same Latin roots as a finger or digit and that is because digits were used for counting when you're little you learn to count on your fingers there are some things in this world that are naturally discreet, for example money, it can be counted so anything that can be counted on your fingers is digital or discrete information. We live in a natural world where most things are continuous. Light there's not discrete values of light there are continuous spectrum of lights between say violet and red. Sound waves are also continuous. Time is continuous, you might have a digital clock which shows you only the second but real time is continuous. Sizes distances now when we measure distances are many… 4:00 - …of these real-world phenomenon we naturally discretize them or what we're doing is digitization. If someone asked you how long is this board, you might say it is 13 inches or twelve and a half inches or some discrete value that you give, and that is because in practice you don't need to tell someone its 13.13 5925615. It might have been how long it really is but we just discretize it to make it more convenient and that's exactly what happens when you give a temperature you just naturally discretize the information so it's easier to convey. As humans we do discretization naturally to reduce the amount of information and for convenience the other reason we discretize information is so we can represent it on a computer. A computer cannot have infinite precision if anyone tries to sell you a computer it says it can represent infinite precision, they are lying do not buy that computer. So all computers have a natural tendency to discretize everything or digitize everything and so when we take information from the natural real world… 5:00 - …you have to discretize it to represent it on a computer. There are more than 50 shades of grey there are an infinite number of shades of grey but a computer
cannot represent an infinite number of shades of grey. It can represent 50 shades of grey or 500 shades of grey or 500 trillion shades of grey but no matter how many shades of grey that computer is representing there has to be a fixed number. It cannot be infinite and that's what we mean when a computer is digital. So that is a summary of discrete versus continuous phenomenon and devices that are digital or analog. Raw Long Form Transcript 0:00 - in this video we're going to discuss 0:02 - discreet information and i'm going to 0:04 - contrast discreet information also known 0:07 - as digital information with continuous 0:09 - information also known as analog 0:11 - information to explore discreet 0:14 - information we're going to look at a 0:15 - little story of an orange person and a 0:17 - blue person out on a sunny day the 0:19 - orange person asked Blue person what is 0:21 - the temperature the blue person replies 0:23 - about 22 degrees Celsius perhaps the 0:27 - blue person has a fancy app on their 0:29 - phone and they look at their app and say 0:30 - oh it's 22.3 degrees Celsius but it's 0:34 - very unlikely that the blue person would 0:36 - say all its 22.3 175 78 321 degrees 0:40 - Celsius this happen in real world you 0:43 - would probably be very suspicious of 0:45 - that blue person however that might be a 0:47 - more accurate reflection of what the 0:49 - real temperature is that is because 0:51 - temperature in the real world is a 0:53 - continuous phenomenon 0:54 - let's think of a continuous system like 0:56 - a mathematician consider the number of 0:58 - numbers that exist between 22 and 23 1:01 - well you might start off and say 22.5 1:04 - 22.1 but as you realize you could answer 1:07 - 22 . all one between 22 and 22.1 and 1:10 - then you can answer 22.0 one in there so 1:13 - it turns out there's actually an 1:15 - infinite number of values that exists 1:17 - between 22 and 23 the number system we 1:20 - use is completely continuous if you give 1:23 - me any two numbers i can find a number 1:25 - that exists between those two numbers
1:26 - and that exists for any number in our 1:28 - numbering system so temperature is like 1:31 - numbers in that way there's a infinite 1:33 - precision that we could use to determine 1:35 - what the temperature is if you have an 1:36 - old-school mercury thermometer if you 1:39 - can zoom in at the Micro Micro 1:41 - microscopic level you could actually 1:43 - measure at great resolution what the 1:46 - actual temperature is now full 1:48 - disclosure for all the quantum 1:49 - physicists out their temperature may not 1:51 - be continuous at the quantum level but 1:54 - that is way beyond the scope of this 1:56 - course so on the Left we have an 1:58 - old-school mercury thermometer which is 2:00 - a continuous device on the right we have 2:02 - a digital thermometer which is what 2:04 - you're probably more used to using the 2:06 - mercury thermometer is continuous 2:08 - whereas the digital thermometer is 2:10 - discreet 2:11 - so what do you mean by discrete the 2:13 - digital thermometer might for example 2:15 - jump from 22.2 degrees to 22.3 degrees 2:19 - there's no in-between 2:21 - earlier I mentioned that numbers there's 2:22 - an infinite number of numbers between 2:24 - any two numbers but on a digital 2:26 - thermometer you won't have that you'll 2:28 - never have 22.25 degrees it's either 2:31 - going to go 22.2 or 22.3 that's what we 2:34 - mean by discrete is only specific values 2:36 - that the thermometer can display its not 2:39 - continuous now of course you can get a 2:41 - fancier digital thermometer with more 2:42 - precision but regardless of what the 2:44 - precision is it still going to be 2:45 - discreet when we see a digital device 2:47 - whether it's a digital thermometer or 2:49 - digital camera 2:51 - what it really means is that it can only 2:53 - measure things in discrete levels it is 2:55 - not continuous so when you see the word
2:58 - digital referring to a device it doesn't 3:00 - necessarily mean it's electronic or use 3:02 - a computer what it really means is that 3:04 - it measures discreet phenomenon 3:06 - similarly when you see an analog device 3:08 - it means it's continuous discrete and 3:10 - continuous or opposites just as digital 3:12 - and analog are opposites the word 3:14 - digital itself comes from the same Latin 3:16 - roots as a finger or digit and that is 3:19 - because digits were used for counting 3:21 - when you're little you learn to count on 3:23 - your fingers there are some things in 3:26 - this world that are naturally discreet 3:28 - that's for example money and money can 3:30 - be counted so anything that can be 3:31 - counted on your fingers is digital or 3:35 - discrete information we live in a 3:37 - natural world where most things are 3:39 - continuous light there's not discrete 3:42 - values of light there are continuous 3:45 - spectrum of lights between say violet 3:47 - and red sound waves are also continuous 3:50 - time is continuous you might have a 3:52 - digital clock which shows you only the 3:54 - second but real time is continuous sizes 3:57 - distances 3:58 - now when we measure distances are many 4:00 - of these real-world phenomenons we 4:02 - naturally discretize them or what we're 4:04 - doing is digitization if someone asked 4:06 - you how long is this board you might say 4:08 - it is 13 inches or twelve and a half 4:11 - inches or some discrete value that you 4:14 - give and that is because in practice you 4:16 - don't need to tell someone its 13.13 4:18 - 5925615 might have been how long it 4:22 - really is but we just discretize it 4:25 - to make it more convenient and that's 4:27 - exactly what happens when you give a 4:28 - temperature you just naturally 4:29 - discretize the information so it's 4:31 - easier to convey as humans we do
4:34 - discretization naturally to reduce the 4:37 - amount of information and for 4:38 - convenience 4:39 - the other reason we discretize 4:40 - information is so we can represent it on 4:43 - a computer a computer cannot have 4:45 - infinite precision if anyone tries to 4:47 - sell you a computer it says it can 4:49 - represent infinite precision they are 4:51 - lying do not buy that computer so all 4:53 - computers have a natural tendency to 4:55 - discretize everything or digitize 4:57 - everything and so when we take 4:59 - information from the natural real world 5:01 - you have to discretize it to represent 5:03 - it on a computer there are more than 50 5:06 - shades of grey 5:07 - there are an infinite number of shades 5:09 - of grey but a computer cannot represent 5:11 - an infinite number of shades of grey it 5:14 - can represent fifty shades of grey or 5:16 - 500 shades of grey or 500 trillion 5:19 - shades of grey but no matter how many 5:21 - shades of grey that computer is 5:22 - representing there has to be a fixed 5:24 - number it cannot be infinite and that's 5:26 - what we mean when a computer is digital 5:29 - so that is a summary of discrete versus 5:31 - continuous phenomenon and devices that 5:34 - are digital or analog
