The Avengers have battled to save Earth from an alien invasion, the evil Loki and now, in the latest movie, face off against the killing machine Ultron. They do this, of course, with the help of numerous superpowers - including Iron Man’s suit, super-healing abilities and Captain America’s indestructible shield. But just how scientifically sound are some of these powers, and do any of them hold up to the laws of physics and chemistry as we know them? Scroll down for video . The American Chemical Society in Washington explained the science behind the Avengers in a video. It looks at the composition of Iron Man's suit - said to be a gold-titanium alloy in one of the movies - and Captain America's shield. The video also explains the science behind super-healing abilities . In a video for Reactions, the American Chemical Society took a look at the science of Marvel's Avengers. It begins looking at Tony Stark, better known as Iron Man when he dons his iron suit of armour. His original suit, made only of iron, would have weighed around 70kg (150lbs) according to the ACS - not very comfortable or easy to move around in. He later upgrades it to a gold-titanium alloy, but that would actually make things worse explained the video. ‘That suit would probably weigh around 160kg (350lbs), which might work for the Hulk but not for Tony Stark,’ said the narrator. However, Dr Raychelle Burks continued that it is later made of a nickel-titanium alloy called nitinol. This is ‘strong but light, and can be reformed after taking damage,’ she said. ‘There may also be some graphite reinforced with carbon fibre, which can take a lot of heat - useful if Iron Man doesn’t want to singe his feet using those rocket boots.’ Tony Stark, better known as Iron Man when he dons his iron suit of armour and played by Robert Downey Jnr (pictured), made his original suit out of iron. He later upgrades it to a gold-titanium alloy, but according to the ACS that would be heavy and uncomfortable - perhaps better for the Hulk than Iron Man himself . None of this would work, though, without Stark’s own portable nuclear power station - the Arc Reactor. In Iron Man 2 this uses palladium - but we soon learn this is poisoning and killing the character. So instead, he creates a new element - and Dr Burks said this might not be as far-fetched as it seems. He uses his own particle accelerator to smash the nuclei of atoms together and make a new type of atom, which is not entirely dissimilar to the experiments taking place at real-life accelerators such as Cern. ‘Scientists have made 20 synthetic elements this way, so it’s not unbelievable that Stark would have made new elements to power his suit,’ said Dr Burks. The main skeleton of Raytheon;s exoskeleton, shown, is made from high-strength aluminium and steel, and weighs about 95kg (209lb) Iron Man’s superpowers don’t stem from a radioactive spider bite or exposure to gamma rays; they are simply the result of some very clever engineering - and quite a bit of money too. It makes sense then that we should try to replicate his powerful suit, and some companies are already coming incredibly close. Raytheon, an American defence contractor, has developed a super-strong robotic exoskeleton for the US Army. Soldiers can simply strap into the suit and its high-pressure hydraulic system will enhance their strength, agility and endurance, enabling them to be extremely physically active without risk of exhaustion or injury. The current version must be tethered to its power source, an internal combustion hydraulics engine, but an untethered version is expected to be operational by 2020. It’s not just the military that can benefit from exoskeletons, though, as Lockheed Martin has also designed a suit specifically to help workers operate heavy machinery. The Fortis helps to carry the weight of tools, enabling the operator to work for longer between breaks required to recover from muscle fatigue. Source: How It Works issue 72, 'Real-life superpowers' Tony Stark's suit is powered by his famous Arc Reactor, but in Iron Man 2, we learn that its palladium fuel source is slowly killing him. So instead, Stark creates a new element - and this might not be as far-fetched as it seems as it follows somewhat similar principles to those taking place at Cern . Stark isn’t the only one with super-human abilities, though. Both Captain America and Black Widow have super strength, quick reflexes - and, most interestingly - the ability to heal quickly. ‘In normal healing, a type of white blood cell called a macrophage fights infections and oversees the repair process,’ explains Dr Burks. While this can take two to five days in regular humans, the macrophages of Captain American and Black Widow appear to be super productive, helping them heal even more quickly. Both Captain America (left) and Black Widow (right) have super strength and quick reflexes, while and - most interestingly - the ability to heal  quickly. This could be due to having advanced macrophages, which let them fight infections and repair their bodies much quicker than us regular humans . And Captain America also has his shield as protection, which can deflect bullets, grenades, lasers and so on. Most of its protection appears to come from steel, although this is not a great shock absorber - and somehow Captain America is able to survive even the heaviest of blows from Thor’s hammer. The reason is thanks to the imaginary mineral called vibranium which, while fictional, has some science at its core. Captain America also has his shield as protection, which can deflect bullets, grenades, lasers and so on. The reason is thanks to the imaginary mineral called vibranium - which, while fictional, has some science at its core. It appears that this material can turn vibrational energy from an impact into light energy . ‘This material can absorb a near infinite amount of vibration energy without getting too hot or melting,’ explains Dr Burks. As evidenced by a flash of light as Thor’s hammer hits the shield, it appears this material can ‘convert vibrational energy to light energy,’ keeping the Captain safe. Of course, you have to suspend disbelief just a bit to assume this is possible - but perhaps the Avengers have more of a root in science than you thought.
Washington's American Chemical Society video explains the Avengers . It looks at the composition of Iron Man's suit and Captain America's shield . And it also explains science behind Black Widow's super-healing abilities . The verdict is that some - but not all - of the science is plausible .