Memory foam was developed in 1966 under a contract by NASA’s Ames Research Center to improve the safety of aircraft cushions. Ames scientist Chiharu Kubokawa and Charles A. Yost of the Stencel Aero Engineering Corporation were major contributors to this project. Yost named the temperature-sensitive memory foam “temper foam”.
When NASA released memory foam to the public domain in the early 1980s, Fagerdala World Foams was one of the few companies willing to work with the foam, as the manufacturing process remained difficult and unreliable. Their 1991 product, the “Tempur-Pedic Swedish Mattress” eventually led to the mattress and cushion company, Tempur World.
Memory foam was initially too expensive for widespread use, but in recent years it has become cheaper. Its most common domestic uses are mattresses, pillows, and mattress toppers.
A memory foam mattress is usually denser than other foam mattresses. This makes it more supportive, but also heavier. It is often seen as a good compromise between the comfort of a soft mattress and the solidness of a firm one. Memory foam mattresses often sell for more than traditional mattresses.
The property of firmness (hard to soft) of memory foam is used in determining comfort. Firmness is measured by a foam’s indentation force deflection (IFD) rating. However, it is not an accurate measure on “soft” and “firm”. A higher-IFD foam, with a lower density can feel soft when compressed.
Memory foam has an open-cell structure that reacts to body heat and weight by ‘molding’ to your body, helping relieve pressure points, preventing pressure sores, etc. Most memory foam has the same basic chemical composition, however the density and layer thickness of the foam means different mattresses feel very different. A high-density mattress will have better compression ratings over the life of the bedding. The lower density will suffer from slightly shorter life due to the compression that takes place after repeated use.