Density of earth:

The density of the Earth is approximately 5.51 gm/cubic cm. If you could mix up the Earth so that all of its mass was evenly distributed, and then took a 1 cm cube and put it on scale, it would weigh around 5.51 grams. This makes Earth the densest planet in Solar System. The surface of Earth is rock and water mostly, so scientists have long suspected that the planet's high density comes from large quantities of iron present in the core. This suspicion was confirmed in the year 1936 by seismologist Inge Lehman, who was measuring how seismic waves passed through the Earth. He detected that waves bounced off solid iron core of the Earth.

Earth is densest planet in the Solar System, and tiny Mercury, at 5.43 g/cm³approximately. One surprising fact is that Mercury would be denser than Earth; but, the earth has much more mass, and so it compacts itself more tightly than Mercury. If Mercury and Earth were of the same size, Mercury would have been denser. All the numbers that were provided are so close to each other, but, that they can each be assumed to be valid. Some of the assorted numbers which can be given would be: 5.5, 5.52, and 5.15 g/cm³ Density is found by dividing the mass by the volume (ρ = m/V). A scientist Henry Cavendish assembled an apparatus which consisted of a suspended metal rod with 2 lead balls hanging from it. He placed masses of metal near these balls in order to measure the force of attraction in between them. Likewise, then he could find the attraction on a mass the size of the Earth and then determine the density of it.

The mass of the Earth is found to be 5.98 × 10²¹ metric tons. As the Earth is a spherical in shape, the formula used to find the volume is 4/3πr³. The volume of the Earth is approximated as 1.08 × 10¹² km³. As the Earth's mass is so large, it makes a gravity which compresses it more than every other kind of inner planet.