First designed in the mid-1960s for NASA airplane seats, memory foam is made from a substance called viscoelastic. It is both highly energy absorbent and soft.
Memory foam molds to the body in response to heat and pressure, evenly distributing body weight. It then returns to its original shape once you remove the pressure.
In addition to protecting against impact, these properties make memory foam very comfortable. After its "virgin flight" for NASA, memory foam made a foray into other applications. For example, it was used as cushioning in helmets and shoes. Medicine found a use for it in prosthetics and products to prevent pressure ulcers such as seating pads for people who are severely disabled.
Then, memory foam really took off. It's now we…