The brain, our fragile and precious asset, is wrapped in the thick shell of the skull. In most cases, the skull protects our brain from all possible harms in daily life, so we must protect our brains. The helmet is the most common protection form. However, the helmet should not only be a thickened protection shell, but also match the usage scenarios while providing the protection effect as much as possible. The main function of a bicycle helmet is to prevent the head's direct collision with the ground.
Wearing bike riding helmet is likely to save our lives when an accident occurs. However, bicycle riders have been arguing whether it is necessary to wear a helmet. Some studies have shown that car drivers will be closer to cyclists wearing helmets when driving, while other studies have found that as long as they wear helmets when riding bicycles, cyclists will be more self-conscious. After carefully studying the helmet's actual role in an accident, Donal McNally, a bioengineer at the University of Nottingham, UK, came to an unquestioned conclusion. McNally said: "I have done a lot of experiments to simulate the actual riding impact, and the results show that the helmet can protect users effectively, especially for children."
Although most riding helmets are light, they are effective. The helmet's outer shell is made of hard materials, such as carbon fiber or polycarbonate, which can disperse the impact. Helmets are usually designed in the shape of an "eggshell" that will dent during impacts, just like a car's impact buffer to absorb energy. There is a layer of expanded polystyrene inside the helmet, which will permanently deform and absorb energy when impacted, further reducing the impact on the wearer's skull. Expanded polystyrene, commonly known as styrofoam, is a high-quality version of the polystyrene-the ubiquitous disposable foam lunch box is made of polystyrene.