A scientist tests how quickly each of the following substances ...

[plus1]

A scientist tests how quickly each of the following substances will settle out of water.
 
  To measure this property, she separately tests each of the following by placing 100 grams of the substance and 500 milliliters of water into a 1-liter jar with a tight lid. She then shakes the jar violently for 1 minute and places the jar on the lab table. Which one of the following would settle the fastest, creating the clearest water in the fastest amount of time? A) Gravel
  B) Clay
  C) Silt
  D) Sand

Question 2

Using what we know about thermal expansion, conduction of heat, and viscosity, should we expect thermal convection within Earth's core?
 
  What will be an ideal response?

[frogdreck123456]

Answer to Question 1

A

Answer to Question 2

The outer core consists mostly of liquid iron that has very low viscosity but is a very good conductor of heat. The high conduction prohibits convection from occurring. The inner core consists mostly of solid iron, which has high viscosity and is a very good conductor of heat. Its thermal expansion is slightly less than rocks. Most rocks have a volume-expansion coefficient in the range of 1533 x 10-6 per degree Celsius. Iron is slightly lower, 1012 x 10-6 per degree Celsius. Putting together all three factors makes it highly unlikely that convection occurs in the inner core.

[plus1]

Excellent

[samiel-sayed]

Gracias!