Computer Science Basics · Professor Erklärbär

Episode 1

computer science in everyday life: alarm clock, bus app, music recommendations, checkout, traffic lights, fitness watch
information + automation = computer science (in German: Informatik)
data or information? What the number 8003 means depends on the context
the IPO model: input, processing, output and storage – shown with a fitness watch, a games console, a checkout and a vending machine
hardware and software – and what the operating system does in between
algorithms: unambiguous, executable, finite – tested with the robot butter sandwich
a short history of computing in 60 seconds
fields, jobs and paths into computer science
the four most common misconceptions about computer science

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Episode 2

why only 0 and 1: light switches, transistors and noise
bits and bytes – and why every extra bit doubles the possibilities (2⁸ = 256)
place values in the decimal and the binary system: 1101 = 8 + 4 + 1 = 13
decimal to binary: with powers of two (200 = 1100 1000) and with repeated division
the finger trick: count to 1023 with two hands
binary arithmetic: 1 + 1 = 10, column addition 13 + 6 = 10011
kB, MB, GB, TB – and why 1 TB shows up as 931 GB (1000 versus 1024)
the four most common mistakes with binary numbers

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Episode 3

everything is code: the same byte is 65, the letter A or a dark grey
text with ASCII: A = 65, a = 97, “Hi” as two bytes
Unicode and UTF-8: why ä needs 2 bytes, € 3 and an emoji 4 – and where “fÃ¼r” comes from
pictures: pixels, RGB colours, Minecraft textures and Full HD
sound: sample rate (44,100 per second) and resolution (16 bits)
calculating file sizes: photo, song and video
compression: run-length encoding, lossless (ZIP, PNG) and lossy (JPEG, MP3)
the four most common mistakes about data

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Episode 4

true or false: statements as 1 and 0
AND: switches in series and two-hand control on a press
OR: switches in parallel, a doorbell at two doors and the filter in an online shop
NOT: the fridge light and the pause button in a game
XOR: the stairwell light with two switches
gate symbols: European rectangles (&, ≥1, =1) and American shapes
an alarm system with eight rows in its truth table – and redstone in Minecraft
the half adder: how gates compute
the four most common mistakes in logic

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Episode 5

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Episode 6

algorithms in everyday life: recipes, assembly instructions, the Rubik's Cube, navigation – and what “the algorithm” on TikTok means
four properties: unambiguous, executable, finitely described, terminating (and why shampoo instructions never end)
sequence, selection, repetition – no program needs more
a flowchart for a pedestrian crossing with the standard symbols
structograms (Nassi–Shneiderman) and pseudocode
the robot bear: 12 commands become 5 lines with a loop
searching: 73 in six questions instead of up to a hundred
insertion sort with playing cards
the four most common mistakes

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Episode 7

machine code and high-level languages – JavaScript, Java, C++, Scratch and Python
Thonny or an online editor: code on top, console below
print("Hello World"), quotation marks and comments
variables as labelled boxes: score = score + 10
int, float, str, bool – and why the type matters
arithmetic: 7 / 2, 7 // 2, 7 % 2 and a year of pocket money (€780)
input(): Hello Mia!, your age in days and the “3 + 4 = 34” trap
SyntaxError, NameError, TypeError, ValueError – read from the bottom
the four most common mistakes