When we look at a rock in water, we may be amazed at how it appears to float or be light on the surface of the water. Interestingly, this phenomenon is not limited to rocks alone, but can also be observed in other objects such as wood, plastic, and even some metals.

In this article, we will discuss some of the reasons that make a rock appear light in water.

Buoyancy:

The first reason that makes a rock appear light in water is what is known as buoyancy. Rocks and other objects that float on the surface of the water have a lower density compared to the density of water. Therefore, the weight force acting on the rock is less than the weight force acting on the water. As a result, the rock can float on the surface of the water.

Composition of the rock:

The second reason that makes a rock appear light in water is its internal composition. Rocks that are made of lightweight materials such as gypsum and limestone have a lower density compared to rocks that are made of denser materials such as granite and basalt. Therefore, lighter rocks will float on the surface of the water more easily than heavier rocks.

Size and shape:

The third reason that makes a rock appear light in water is its size and shape. Large rocks require more force to sink in water, but if the rock is small, it will be easier for it to float on the surface of the water. This also applies to the shape of the rock, where rocks that are shaped to float will float easily on the surface of the water.

Apparent density:

The fourth reason that makes a rock appear light in water is its apparent density. Apparent density refers to the weight that a person feels when carrying the rock in water, not the actual weight of the rock. When the apparent density of the rock is less than the density of water, the rock will float on the surface of the water.

In conclusion, rocks appear light in water due to several factors, including buoyancy, internal composition, size and shape, and apparent density. All of these factors indicate that the rock can float on the surface of the water easily, making us feel amazed and impressed when we look at it.

You can conduct the experiment yourself through the Vlaby platform for virtual science experiments