Metal foam

• Metals such as aluminium (and sometimes steel or titanium) can be made into a foam by injecting gas into the metal when it's a liquid state. This creates a foam that is very lightweight and has high compressive strength - a porous material that can absorb energy well

  
• Metal foams are also used in filtration due to their porosity, and are currently being developed for use in prosthetics for animals. The hope is to create prosthetics that are lighter and more comfortable for the user
• Metal foam can be used as soundproofing or for crash protection in vehicles as it's light enough to be carried in cars without reducing their speed
• Metal foam is also being developed in the use of body armour, again because it's lightweight and strong