#_____
Signature: ____________________________________
The Earth’s Changing Surface
HOMEWORK #9
DIRECTIONS:
o Read the paragraph below and answer the questions that follow.
Heading:_________________________
________________________
________________________
________________________
________________________
Do you know how a cold pot of water is heated on a stove? When the liquid close to a heat source is
heated, its particles move faster and spread apart. As a result, the particles of the heated water occupy more
space. The water's density decreases. The warm, less-dense fluid rises. The warm liquid spreads along the
surface, cools, and the water's density increases. Gravity causes the cooler, denser water to flow to the
bottom of the pot, where it is heated. This motion creates a circular flow called a convection current.
Convection currents are used to transfer heat within a fluid (a liquid or a gas).
Look at the four statements listed below.
DIRECTIONS:
o Put the statements in the correct order to complete the description of a convection current.
o The first step has been chosen to get you started.
___step 1__ Heat warms the liquid near a heat source and decreases its density.
__________ The warm liquid spreads along the surface, cools, and becomes denser.
__________ The warm, less-dense liquid rises.
__________ Gravity pulls the cooler, denser liquid down to the heat source where it is heated again.
DIRECTIONS:
o Put the statements in the correct order, 1-4, to complete the description of a convection current in the
Asthenospere.
__________ As it sinks, it returns back towards the Mesosphere, heats up, and repeats creating a circular
current or movement called a convection current.
__________ It becomes less dense and rises.
__________ As it rises towards the Lithosphere, it cools down, becomes denser, and sinks.
___step 1__ The heat from the Mesosphere causes the magma at the bottom of the Asthenosphere to heat
up.
1. Which is the least dense?
A. Hot water
B. Cold water
C. Neither
D. Can’t tell
How do you know? Use evidence from today’s demonstration. Write at
least 2 sentences. _______________________________________________
_______________________________________________________________
_______________________________________________________________
2. If you mixed cold and hot water what would you expect to happen? Think about the differences in
density.
Explain. ________________
A. The hot water would begin to sink and form a layer on bottom.
_______________________
B. The cold water would begin to sink and form a layer on bottom.
_______________________
C. The cold water would freeze and turn into ice.
_______________________
D. The hot water would begin to boil and evaporate.
_______________________
3. Which layer of the earth do convection currents form in?
A. Lithosphere
B. Asthenosphere
C. Outersphere
D. Solidsphere
4. What is a convection current? (Hint: Use your NOTES/CLASSWORK sheet from today as a help)
____________________________________________________________________________________
5. Draw two convection cells in the space below.
o Color code the arrows indicating the temperatures. (Write in the color if you don’t have
crayons or markers)
o Label the Lithosphere,
o Red = hot/warm
Asthenosphere, Mesosphere,
o Blue = cold/cool
Outer Core, and Inner Core.
o Label each rising and sinking section as:
o Less Dense
o Denser