Why do some elevators stop at every floor on Saturdays?

Because of Shabbat, Judaism's weekly day of rest. From just before sunset on Friday until three stars appear on Saturday night, Jewish law forbids melakhah, a word usually translated as "work" but better understood as deliberate, creative activity. For many Orthodox and some Conservative authorities, that includes switching electric devices on or off; one view is that the tiny spark inside a switch counts as lighting a fire. Pressing a lift button is a problem. So a "Sabbath elevator" is set to stop automatically at every floor, and people simply step on and off.

The forbidden activities are not a random list. Tradition counts 39 categories, derived from the kinds of work needed to build the Tabernacle, the sanctuary described in the Bible. Many rabbis note what they share: they are creative, they exert control over the world around you. Shabbat is about stopping that for a day, and indeed the word can be translated as "ceasing".

The same logic produced Shabbat clocks that switch lights on and off by timer, and "Sabbath mode" on some ovens and fridges.

Not everyone agrees on the details. Some Conservative authorities reject the ban on electricity entirely, and many rabbis say the automatic lift is really meant for the frail and disabled. One rule is shared: saving a life overrides Shabbat, so you must drive a woman in labour to hospital.