Guided path · 3 lessons · about 15–20 minutes
How websites work
Explain the difference between finding a website, fetching its content, and running its code.
No setup needed. These are simplified teaching models; the full explanations describe their limits.
Lesson 1 of 3 · DNS
How does a name find a website?
A name lookup gives an address. It does not send the page.
DNS found the address. Has your browser received the web page yet?
Make a prediction in your head, then use the experiment to test it.
Try the model
Step from a name to an address, then a protected connection and a page.
You type a name. What happens next?
A website name is easy for us to remember. Your browser still needs to find where to send its request.
Check your understanding
DNS found the address. Has your browser received the web page yet?
Loading the understanding check… If it does not appear, read the full explanation below.
The idea to keep: Finding, connecting, and receiving are different jobs.
Go deeper & discuss this idea
Lesson 2 of 3 · Caching
Why am I still seeing the old page?
A fresh saved copy can remain behind an updated original.
A cache saved version 1 ten seconds ago. Its freshness window is 30 seconds. The original is now version 2. What can a normal load show in this model?
Make a prediction in your head, then use the experiment to test it.
Try the model
Update the original, reload, and advance a pretend clock.
Start by loading the page. Where do you think the copy will come from?
Try this: load → update original → load again → wait twice → load.
Check your understanding
A cache saved version 1 ten seconds ago. Its freshness window is 30 seconds. The original is now version 2. What can a normal load show in this model?
Loading the understanding check… If it does not appear, read the full explanation below.
The idea to keep: Fresh means reusable by a rule, not necessarily newest.
Go deeper & discuss this idea
Lesson 3 of 3 · Serverless
If there is no server, who runs it?
The provider manages servers. You still own your application decisions.
The model scales managed capacity to eight jobs. What can we conclude about a real serverless service?
Make a prediction in your head, then use the experiment to test it.
Try the model
Compare a fixed allocation with simplified managed capacity.
Learn by changing one thing
Who looks after the computers?
Move the traffic slider. Compare a fixed capacity you chose with capacity managed by a provider.
Instant one-slot-per-job scaling is a visual simplification, not a promise. Real services have limits, startup delays, queues, and pricing; zero jobs does not mean a zero total bill. Inputs stay on this page; no account, file, or network is changed.
Check your understanding
The model scales managed capacity to eight jobs. What can we conclude about a real serverless service?
Loading the understanding check… If it does not appear, read the full explanation below.
The idea to keep: Managed infrastructure is not unlimited capacity or automatically free.
Go deeper & discuss this idea
A good place to pause
You have explored how websites work.
You answered all three understanding checks. Now explain one idea to someone else, or revisit the experiments with a different prediction.
A personal learning record, not a certification or independent assessment.