Some basic science help?

[Steezie]

Ok, Im making a birthday present for my fiancee. Shes a science nut and I love working with Terragen so I have a project where I've created "pictures" in Terragen of fake planets and I have descriptions typed up next to the picture.

Problem is I cant really find some of the basic stuff so I have a few questions, I will be adding to these.

1. What would liquid mercury do on a planet with a high gravitational pull and with clouds of mercury vapor and iron as well as electrical storms?

2. What would a body of water look like on a planet with massive quantities of silicon sand?

 

[CrusaderKing]

1. What would liquid mercury do on a planet with a high gravitational pull and with clouds of mercury vapor and iron as well as electrical storms?

Elemental mercury has a boiling point at over 600 K at STP.

2. What would a body of water look like on a planet with massive quantities of silicon sand?

Sand is silicon dioxide and we have plenty of it here.

 

[Michael]

The liquid mercury would tend to form an ocean, and the silicon sand would tend to sink underneath the water just as sand is heavier than water here on earth.