Michael Faraday 18th century General Electric     1911

Imagine if, instead of using the fridge in the kitchen, you had to keep meat and fish preserved in barrels of salt or smoked in a smoke house out back? Imagine how large the grocery store would be if it used snow and ice, cool streams, springs, caves and cellars to keep ice cream frozen and TV dinners chilled! Those grocery store and kitchen fridges are the latest development in a 3,000 year evolution of refrigeration. As early as 1,000 BC, the Chinese cut and stored ice for use in warmer weather. 500 years later, the Egyptians and Indians made ice on cold nights by leaving water in wet earthenware pots outside. In 18th century England, servants collected ice in the winter and put it into icehouses, where the sheets of ice were packed in salt, wrapped in strips of flannel material, and stored underground to keep them frozen until summer. Ice houses evolved into smaller ice boxes that were made of wood and lined with tin or zinc and insulated with cork or sawdust. Sometimes even seaweed was used to keep ice cold and "refrigerate" food. A drip pan collected the melted water and someone had to empty it every day. In the 18th century, scientist Michael Faraday liquefied ammonia to cause cooling. Today's fridge and freezer (not to mention air conditioners and de-humidifiers) work on an idea adapted from Faraday's experiments. Rerfigerators compress a gas into a liquid. This process generates heat (which you can usually feel at the back of your fridge). The liquid is pumped through pipes to the inside of fridge and allowed to expand back into a gas. This process absorbs heat, cooling the inside of the fridge. The gas is pumped back out and the cycle repeats. People didn't switch from ice boxes to modern refrigerators voluntarily. Warm winters in 1889 and 1890 in the U.S. created shortages of natural ice. Grocery stores and food industries were forced to use large refrigerators to freeze and store fish, dairy products and meat so they wouldn't go bad. In 1911 General Electric released a home refrigerator invented by a French monk. This model used compressors that were driven by long belts attached to motors in the basement or in a neighbouring room. The dial in the back of the fridge that controls temperature was added in 1918. A typical fridge at that time looked like a wooden cabinet with a water-cooled compressor. Later, more stylish steel and porcelain cabinets replaced the wooden ones. Freezers with ice cube trays were added on top. Automatic ice makers started churning out ice in the 1950s and 60s. Now, the fridge is one of the most common home appliances. It's found in 99.5 per cent of North American homes!