Go on. Look inside.

Some shopping carts have a hidden brake in one wheel.

Almost everyone has wondered what happens if an elevator's cable snaps.

Child-resistant medicine caps hide a two-part lock that only opens when you push down and turn at the same time.

Every popcorn kernel is a tiny sealed pressure cooker.

An onion keeps two chemicals stored apart inside its cells.

That tiny hole in your plane window is there on purpose.

Inside an ordinary door lock, five split pins decide which key is allowed to turn.

Your microwave door is full of holes, so why doesn't it cook you?

Every airbag has a small pyrotechnic charge inside it.

A small pan fire looks easy to put out with water, but this is what happens inside the pan when you try.

A gas pump nozzle shuts itself off when your tank is full, with no sensor, chip or electricity.

Many smoke alarms hold a tiny amount of radioactive americium.

That little red glass bulb in a ceiling sprinkler works as a heat fuse.

Many safes hide a thin glass plate behind the lock that holds spring-loaded steel bolts back.