How does a computer remember things even after you turn it off?

You save a file, switch the computer off, walk away — and tomorrow it's still there. But other things vanish the second the power blinks. So what actually holds your stuff in the dark? Let's pull the plug and find out.

1What "remember" really means

Memory is just bits — and bits need something to hold them

You only need two ideas. Watch each one:

Everything is on/off bits

A note, a name, a photo — it's all tiny bits. Each bit is just on or off, a 1 or a 0. Put enough of them in a pattern and you've spelled something.

Something has to hold each bit

A bit can't float by itself. Some bits are held up by electricity flowing right now. Others are snapped into a physical state that stays on its own.

2Two kinds of memory

The thinking desk vs the locked drawer

A computer doesn't remember in one single way. It has two memories that work in opposite ways:

Working memory

The thinking desk

Super fast — but it only holds a bit while electricity keeps pushing on it.

Storage

The locked drawer

Slower — but each bit clicks into a physical state that stays with no power at all.

3Your turn — write something to remember

Type a little note and watch both banks light up

Type a short word. The same note gets written into both memory banks at once — watch each one light up its bits to hold your pattern.

Working memory

held by flowing power ⚡

Storage

locked into place 🔒
up to 5 letters — try your name

4Now pull the plug

Your note is in both banks. What happens when the power dies? 🔌

Same note, both banks holding it. The big test: cut the power and watch. Guess first — then pull the plug.

Power:ON ⚡

Guess before you pull the plug

Before you pull the plug, predict: which kind of memory keeps your file, and which loses it?