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.
When the Occupational Safety and Health Act passed in 1970, steel-toe boots became a standard in the American workplace, preventing thousands of on-the-job injuries. Today's technology has only increased the variety of work boots available, and it's important to understand the differences before purchasing a pair.
The boot is different because of an asymmetrical toe box to match the curve of the foot as well as a liner pre-shaped for the navicular bone of the ankle. Tecnica cites the boot shell is shaped to be closer to the arch of the foot. There is a groove for the Achilles tendon.