Mattress Ratings >> Memory Foam Mattress Ratings
What Is Memory Foam?
Memory foam is constructed from polyurethane with additional chemicals that increase its density. It is often referred to as visco-elastic polyurethane foam. The foam is made up of millions of spherical shaped, open cells.
What makes memory foam unique is that it is temperature and weight sensitive.
Temperature sensitive
Memory foam is temperature sensitive. In other words, memory foam is firmer in cool temperatures (more viscous) and softer in warm temperatures (more elastic).
Higher density memory foam, such as that offered by Tempurpedic® is particularly temperature sensitive in that it responds to body heat by moulding itself to the shape of a person's body within minutes.
This quality explains the reason people often experience a "melting" feeling when lying on memory foam. High density memory foam can be quite firm even in room temperature. A lower density memory foam is less temperature sensitive and remains more pliable in colder temperatures.
Weight sensitive
Memory foam is also weight sensitive. Unlike traditional foam that compresses and returns to its original shape right away, memory foam cells compress completely and spread their air pressure to other cells. This action allows the foam to better conform to a person's shape and, consequently, reduce pressure points.
The example often used to demonstrate the temperature and weight sensitivity of memory foam is a hand pressed into the foam and then removed, leaving a clear impression in the foam that slowly returns to the original shape.
History
Memory foam was originally developed by NASA to lower the extreme physical pressure put on astronauts when they experience high g-force. The foam was never used by NASA in practice. However, Tempur-Pedic® developed a modified version of the foam called Tempur® and it was used as mattress material in the medical industry. The foam helped immobile patients find better comfort and even health.
Eventually, Tempur-pedic® began selling their product to the non-medical consumer market. Soon other foam makers began offering their own versions of memory foam, often at a lower density and price.
Memory foam is now used not just for mattresses, but for pillows, footwear, chairs and more.