Brownian motion

Pollen grains suspended in water exhibit Brownian motion. How does a particle undergoing Brownian motion move?

• In smooth curves

• Randomly

• Orderly with a pattern

• In straight lines with no change of direction

A student makes an observation using a microscope. She observed some particles which were moving in a zig-zag way. What particles could these NOT be?

• Smoke particles in air

• Dust particles in a room

• Pollen grains in water

• Molecules in a solid bar of steel

Which of the following does NOT describe Brownian motion?

• 
• 
• 
• 

Light and fast moving particles can move heavier particles. Which one is a correct example of the light and the heavy particle?

• Light : air molecule, Heavy : water molecule

• Light : air molecule, Heavy : smoke particle

• Light : smoke particle, Heavy : air molecule

• Light : pollen grain , Heavy : water molecule

What evidence does Brownian motion provide about molecules of a gas or liquid?

• Molecules are close together

• Molecules are far apart

• Molecules move continously but randomly

• Molecules move continously and randomly

Very small pollen grains are suspended in a beaker of water. A bright light shines from the side. Small, bright dots of light are seen through a microscope. The dots move in rapidly changing, random directions. What are the bright dots?

• pollen grains being hit by other pollen grains

• pollen grains being hit by water molecules

• water molecules being hit by other water molecules

• water molecules being hit by pollen grains

A pollen grain in a beaker of still water is viewed through a microscope. Which diagram shows the most likely movement of the pollen grain?

• A

• B

• C

• D

3. Identify the states of matter where Brownian Motion can occur.

• a) Solid, liquid, gas
• b) Liquid, gas
• c) Solid, gas
• d) Solid, liquid

What is an example of Brownian motion?

• The movement of water molecules in a beaker

• The movement of air molecules

• The movement of solid molecules

• The movement of smoke particles in air

4. What is the major problem with trying to observe Brownian Motion?

• a) Molecules are moving too fast
• b) Molecules are moving too slow
• c) Molecules are too big to observe
• d) Molecules are too small to observe