Suppose we have a very big tank, big enough to contain all eight planets of our solar system) full of water. What happens when we drop all eight planets into this tank?

In the huge tank full of water when we put all eight planets, we observe that all the planets sink to the bottom of the tank except Saturn. The planet Saturn apart from having a gorgeous ring, making other planets completely jealous, also has its density less than the density of water.

We all know, when an object is dropped into the water it will either sink or will float, this depends on its density. If the object has higher density than water (1 gm/cm^{3}) then it will sink otherwise it will float.

Let us find out the densities of various planets of our very own Solar System.

Planet | Density (in gm/cm^{3}) |
---|---|

Mercury | 5.4 |

Venus | 5.2 |

Earth | 5.5 |

Mars | 3.9 |

Jupiter | 1.3 |

Saturn | 0.7 |

Uranus | 1.3 |

Neptune | 1.6 |

Source: http://starchild.gsfc.nasa.gov/docs/StarChild/teachers/densities.html

From the table above, we can find that the planet Saturn has density of 0.7 gm/cm^{3} which is less than the density of water 1.0 gm/cm^{3}. Hence planet Saturn will float while the other planets will simply sink down to the bottom of the tank.