The wet bulb temperature is always lower than the dry bulb temperature, and the difference between the two is the wet bulb depression. It needs to be not only hot but also dry, because as the dry bulb temperature approaches the wet bulb temperature, the difference between the two gets smaller, and the cooling effect of the evaporating water follows suit. This varies based on humidity, personal preference and activity, but it generally falls in the low 70s. One hundred percent humidity outside the house means it might rain, and while a swamp cooler won’t cause a downpour in your home, it won’t have any cooling effect either – just the hot, sticky feeling you might associate with swamps. That can be a tall order in the hot, dry climates where swamp coolers function best. Swamp coolers are an open system. A wet bulb temperature above 70 degrees Fahrenheit (21 degrees Celsius) means the swamp cooler won’t be able to adjust the temperature enough to keep it in the comfort zone. They accomplished it by hanging wet blankets across the doors of their homes or, if they happened to be royalty, having servants fan them across jugs of water.

Depending how efficient your swamp cooler is, it can bring the temperature down as much as 95 percent of the wet bulb depression. A swamp cooler operating at 85 percent efficiency can bring the temperature down to a nice, cool 72.3 degrees Fahrenheit (22.3 degrees Celsius), right in the human comfort zone. But the biggest savings is in the electricity – a swamp cooler uses 60-80 percent less electricity than a standard AC. In a standard air conditioner, there are some fairly complicated refrigerants inside, but with a swamp cooler, it’s much simpler. But the mistakes in the Louvre don’t stop there. The restrooms of the Louvre have liquid soap, just like most other public restrooms. In Sudan, a similar cooler was tested and found to keep tomatoes fresh for 20 days – 18 days longer than they would have lasted without the cooler. Instead of cutting short these unexpected exchanges, ask a simple question about someone’s family, or the neighborhood, or almost anything really; this can often lead to a longer conversation, and you are under way and getting some practice talking to strangers. A slash “/” can be used in the same way as the fraction bar. Because of the different ways they work, you can’t run a swamp cooler and a standard air conditioner in the same house.

Egypt. They’re cheap, efficient and good for the environment, but they come with some limitations, so don’t push your standard air conditioner out the window just yet. It is also thought to drive out the evil spirits that cause disease. These words are a common cause of confusion because some people spell them with one L while others use two. In the past, a bucket of water or sand was kept handy at all times – fires were so common they became known risks if someone was attempting to take out an insurance policy. As the civilization grew in around 3500 BC into an agricultural society the level of sophistication and culture began to take shape. A lighthouse overlooking a 100-foot (30.48 meter) cliff, for example, wouldn’t need to be built as tall as one positioned closer to sea level. The clashing of cultures created a need for unique language. The society possessed a robust military force and complex writing system; however, experts still cannot decode the language today, which makes deciphering their history more challenging. Even military GPS technology can’t typically get a fix on a soldier who is in dense tree cover or otherwise concealed. Fache has one of his lieutenants plant a GPS dot in Landon’s pocket.

During medieval times, the 12 nights of Christmas were celebrated by eating one mincemeat pie per night. How do Mexicans celebrate Christmas? Test your Christmas trivia knowledge with the tidbits below. Tinsel was invented in 1610 by a German inventor who based the silvery decorations on a story about a spider’s web that turned into silver when it was made into a Christmas tree. Don’t work well indoors, under dense tree cover or in urban areas with tall buildings. It’s a closed process – leaving a window or door open allows the cool air to escape and makes the air conditioner work harder to supply cold air. The coolers also require a steady supply of water – anywhere from 4.4 to 10.4 gallons (17 to 40 liters) per hour depending on the size. Swamp coolers don’t use any refrigerants. The use of CFCs (chlorofluorocarbons) has been discontinued in developed nations since 1996 by international treaty. It’s recommended to look at the pads, filters, reservoir and pump at least once a month and replace the pads at least twice during the cooling season, or once a month during continuous operation.