The speed of sound depends on the medium that the waves pass through, and is a fundamental property of the material. The first significant effort towards the measure of the speed of sound was made by Newton.
These meet ASTM safety standards and are suitable for most professions. Composite. Many safety boots are nonmetallic-instead of steel or aluminum, they are reinforced with a composite-material steel toe boots, usually made with thermoplastic polyurethane (TPU) or similar materials.
What Are Alloy Toes? Most recently, Alloy toe safety boots have been gaining quite the loyal following. While they are as strong as steel, the only real difference is in the materials and components used in construction. Alloy toes are made from lightweight materials such as titanium, aluminum or a combination of other light materials.