Memory foam or visco-elastic foam was developed by NASA in the mid to late 60's, but was not available to the wider public until the early 1980's.
Memory foam was originally made to improve the safety of aircraft cushions for astronauts.
Dehydrated food, memory foam mattresses, and heart monitors!!!
Although memory foam was invented in the 1960s by NASA there is little evidence of health benefits due to sleeping on a memory foam mattress. Those that sleep on such mattresses say that they enjoy it but scientific studies neither support nor deny any health benefits.
Memory foam is made up of a polyurethane foam material with is molded into a form of a mttress, pillow, and so on.
High density foam is just your typical foam. It does not conform to your body when it heats up like memory foam does.
Instead of purchasing a complete cushion made out of memory foam, it is possible to add one or two memory foam toppers to a regular foam cushion. This will give the support but will not be as hot or as prone to permanent indentations as memory foam.
Memory foam on shoes makes the shoes more comfortable.
Memory foam can be used for a baby mattress. email@example.com
The foam finger was invented in 1904 by Earl Whippie.
The truthful answers is: "It's the thickness you are willing to pay for". One manufacturer I know of makes memory foam mattresses in three configurations: The top 2" of the mattress is memory foam, the top 4" is memory foam, and the whole mattress is memory foam. The price varies accordingly. Personal Note: If you can't afford a memory foam mattress, try a memory foam pillow. Awesome, especially if you're a "side sleeper".
Many products, such as sleeping mattresses, use Novaform memory foam. The memory foam is also used by various companies that sell pillows and blankets.