Question

Despite the fact that stainless steel is much denser than water, a stainless- steel razor blade can be made to float on water. Why?

Short answer

A stainless-steel razor blade can float on water because of the water's surface tension. The surface tension behaves like a 'skin' that isn't broken by the light weight of the blade, and the blade's surface area is large enough to distribute the weight widely, reducing the impact on the water's surface tension.

Step-by-step solution

Understanding density and buoyancy

Density refers to the amount of mass per unit volume. In simple terms, denser objects have more mass packed into a given volume than less dense objects. Buoyancy, on the other hand, refers to the force exerted by a fluid that opposes the weight of an immersed object.

Understanding surface tension

Surface tension is the property of any liquid surface that resists being ruptured. When a small and light object is placed on a liquid, and the object doesn't break the surface, the liquid's surface behaves like a weak elastic sheet supporting the object's weight.

Applying the concept to the razor blade and water

Because the razor blade is very thin and light, its weight isn't enough to break the surface tension of the water, hence, it floats on the surface of the water. The blade's large surface area relative to its weight helps to distribute its weight widely to minimize the impact on the water's surface tension.