Why does iron sink in water but float when dropped in mercury?

Science YouTuber CodyDon Reeder has nearly 2 million subscribers to his Cody's Lab channel. In a recent video, he performed a unique experiment, which was to put mercury in a specialized tank, and then drop an iron anvil weighing about 50kg inside. However, this iron anvil did not sink, even when touched by hand, it still floated like foam floating on the water. Why is that?

In fact, the significant floating or sinking of objects will depend on the difference between the densities of the two objects. Density refers to the amount of space a substance or object occupies, or its volume relative to the amount of matter present in that substance or object, or its mass. Simply put, density refers to the mass of matter in a particular space. The elements at the top of the periodic table will have a lower density than the elements behind it.

Heavy iron block cannot sink in a mercury bath

When discussing density, mercury is often blacked out as a yardstick for other objects. You may be surprised to learn that massive objects, such as iron bars or dumbbells that are normally submerged in water, can float on the surface of mercury.

From the point of view of science, objects with lower density will rise above those with higher density, and vice versa. Based on Archimedes' theorem, any material placed on a liquid will shift part of the liquid. At this point, the displaced liquid will create a buoyant force proportional to the weight of the object. If the buoyant force is stronger than the weight of the material, the object will float. However, if the buoyancy force is weaker, it cannot hold the object, and will cause the object to sink.

Iron blocks cannot be submerged in mercury.

Mercury is a highly dense substance. This metallic element has a density of about 13.5 grams per cubic centimeter - 13 times heavier than water - 1 gram per cubic centimeter. Meanwhile, iron is in the middle, with a density of 7.87 grams per cubic centimeter. From this, we can infer that iron is denser than water. Therefore, it will definitely sink when placed on the water. But, mercury is heavier than iron, and that is why iron floats in mercury.

However, other objects such as sponges, wood, and most fruits are less dense than water, so they will easily float on the surface of the water. Empty bottles and balloons are similar because they are filled with air, which is less dense than water.

Mercury is a highly dense substance.

Mercury has a high density, so some objects you might consider heavy, like a steel ball bearing or a weight, will actually float on the surface of the mercury. Other metals such as copper and nickel, organic materials, such as plastics, wood and stone, as well as some gases and liquids, which are lighter in density than mercury, will also float in them.

Certain substances such as iridium with a density of 22.65 grams per cubic centimeter, platinum at 21.4, and gold with a density of 19.3 higher than mercury will sink. Most radioactive substances called actinides will also not float in mercury. Uranium has a density of 19.1 grams per cubic centimeter, neptunium has 20.45, while lawrenium has 16.6.

And if you are curious whether our bodies can float on the surface of mercury, the answer will certainly be yes. If pure density is taken into account, you will float on a large amount of metallic mercury. That's because the human body is composed of about 65-80% water, which is less dense than mercury. Remember, an object with a lower density will always float on top of a heavier or more dense substance.

Mercury is a chemical element with the symbol Hg (from the Latin name Hydrargyrum) and the atomic number 80. It has many different properties from common metals.

As a silver heavy mass element, mercury is the only metallic element that is liquid at standard conditions of temperature and pressure.

Mercury occurs in minerals worldwide mainly in the form of cinnabar (mercury II sulfide). The vermilion vermillion is obtained by grinding natural cinnabar or synthetic mercury sulfide.

Mercury was known to the ancient Chinese and Hindus, and it has also been found in ancient Egyptian tombs dating to around 1500 BC. In ancient China, India and Tibet, the use of mercury was believed to prolong life, heal fractures, and maintain good health. The ancient Greeks used mercury in ointments and the Romans used it in cosmetics. Around 500 BC mercury was used to form amalgams with other metals. However, in reality its effect is quite the opposite.