How many times have you heard that if you’re leaving your home due to a storm, tornado, hurricane, wildfire, evacuation—or even a long vacation—you should freeze a cup of water and put a penny on top? Well, it turns out that trick doesn’t work and can actually hide the fact that the power’s out.
Freezer hacks…who would have thought?
Legend has it (and an old Lifehacker post that probably helped popularize this idea, unfortunately) that a frozen cup of water with a coin in it can tell you if your freezer went out during a power outage and warmed up.
The idea is that if you are away for weeks, your freezer can lose power without you knowing it. Your food will thaw and maybe start to spoil, but then the power will come back on and your now spoiled food will freeze again. If you leave a penny on a cup of ice, you can check the cup for an indicator. If the penny is on the bottom, the ice should have melted and your food should be thawed. If the penny is still on top, everything was fine.
Besides the hassle of setting up (you have to freeze the cup of water for hours and then put a coin on top), there's an even bigger problem: a coin in a cup is a poor indicator of what's happened, temperature-wise.
