Turning Up the Heat

Lily Orange in Murrieta, California, writes:

A friend received a heating pad as a gift. It has a control panel with four pushbuttons: High, Medium, Low, and Off. My friend asked, “Where’s the On button?” I explained to her that pressing the High button or the Medium button or the Low button, makes the heating pad turn on. She said, “If there’s an Off button, there should be an On button too.” What do you think of her reasoning?

Marilyn responds:

It’s not so hot. (Sorry–couldn’t resist!) The heating pad has no “on” button for the same reason that her oven and iron have no “on” switches: When these appliances are used, one must set the desired “on” temperature, hence the dial or the various heat settings. By contrast, a programmable slow cooker may have a dual “on/off” button to turn on the programming function (and to turn off the heat).