Why will a block of iron float in mercury but sink in water?

Question

Why will a block of iron float in mercury but sink in water?

Answer 1

Instead of thinking that iron floats, think of mercury as the bigger guy who can shove 'his' way closer to the earth, and can push the iron out of the way.

The water, a relative little guy, has to yield to the iron, so the iron 'goes first'; that is, is closer to the earth.

Of course, the technical answer is because the iron is less dense than mercury and more dense than water, but that may seem a bit dry.

Answer 2

you need to knwo the density's of Iron, and mercury and

water the density is 1000 kg·m−3, liquid (4 °C)

remember Density = mass X volume so it depends on Iron Mercury density is 13.534  g·cm−3

Answer 3

Floating & sinking of any substance always depends upon the sign of its terminal velocity in the liquid,

solve ,weight=upthrust+ viscous force.

you will get,

terminal velocity is directly proportional to the difference in the densities of the body &liquid respectively.

In case of water this difference is positive,terminal velocity is positive directed downwards.

In case of mercury,its vice-versa.

Answer 4

because mercury has different substances, and water is just H20. and as block of iron doesn't have to ait in it, it's doesn't have no hollow spaces. it's pre mass. ask youurseld why we don't float automatically on water? best answer?