In a recent study, a team of researchers from the National University of Singapore‘s (NUS) Faculty of Engineering found that sand can absorb more than 85 per cent of the energy exerted against it. The team also found that resistance offered by the sand block increases with the speed at which the projectile travels. In contrast, steel plates have poorer energy absorption capacity against high speed projectiles. This novel finding suggests that sand can potentially be used as a cheaper, lighter and more environmentally friendly alternative to enhance protection of critical infrastructure as well as armour systems. Different nose shapes and masses of projectiles fired at a wide range of velocities were investigated. The impact also results in an extreme frictional force that could potentially break the projectile into pieces. This is due to the pressure and friction offered by the sand grains, which dilate and resist continual penetration of the incoming projectile. In contrast, energy absorption capacity of an equivalent steel plate reduces dramatically as the velocity of the projectile increases, resulting in the projectile passing through it without further obvious resistance. This is also known as the hydrodynamic effect where steel behaves alike to a fluid without material strength with increasing velocity beyond the ballistic limit, which is the minimum velocity required for the projectile to penetrate the target. The team believes that the findings of their study will further expand the wide-ranging applications of sand, which is currently being used extensively in areas such as glass making, building construction and land reclamation.