My Invention On june 8, we returned home from our vacation. Our flight from Tampa FL to Albuquerque NM was 5 hours long. We landed in Albuquerque NM at 6 pm. Then we picked up our baggage and took a shuttle to our long parking. Our car, Subaru Forester 2016, was waiting us . Then we visited Costco to buy some food and drove home to Window Rock. It was 11 PM when we got home. How you can know if, while you were on vacation, your refrigerator was not out of power? Temporary power outage may had happened and all your food in freezer might be spoiled and then might be frozen again. You may eat something and get poisoned. To avoid such possibility, I put in my freezer a bottle filled with with water on one/third. First, I put it horizontally and when the water get frozen, I put it vertically. If power outage will happen then water will melt and gather at the bottom of the bottle. I opened my freezer and check the bottle. The shape of the ice in the bottle was not changed. It means, our freezer was not out of power even temporary. It is safe to heat fully cooked burgers that were stored in the freezer and eat them.