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SIMPLEExplained Simply · #9EP.168 · 24 s

Explained Simply #9: How does the internet travel through glass?

Cover of the lesson: Explained Simply #9: How does the internet travel through glass?Coming to YouTube soon
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// WHAT YOU WILL LEARN

Fibre optics: light pulses bounce along a glass thread (total internal reflection) at about two-thirds of light speed.

// LESSON NOTES

Your video crossed the ocean… through GLASS! 🌊💡

Inside a fibre-optic cable: a glass thread about as thin as a hair 🧵
🔦 A laser blinks: light ON = 1, light OFF = 0.
🔁 The light bounces off the walls of the glass (total internal reflection), so it never escapes.

⚡ How fast? About 200,000 km per second — two-thirds of the speed of light. That's 5 times around the Earth every second!
🌍 Cables on the sea floor carry almost all the data travelling between continents.

Read the voiceover (transcript)
  1. Your video crossed the ocean through glass!
  2. Inside the cable: a glass thread, thin as a hair!
  3. A laser blinks: light on is one, off is zero.
  4. The light bounces off the walls, so it never escapes!
  5. Guess: how fast does it go?
  6. Two hundred thousand kilometres a second!
  7. Sea-floor cables carry almost all of it!
  8. Next: what is a semiconductor, really? Follow for more!

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