Download Thermal Expansion Activity (Teacher version)

Lesson Title: Sea Level Rise:
Measuring Thermal Expansion
Grade Level: 11-12
Subject Area(s): Marine Science
Associated with: Chemistry Unit
Time Required: 1 class period (beginning and end of experiment)
Background
Core samples, tide gauge readings, and,
most recently, satellite measurements
tell us that over the past century, the
Global Mean Sea Level (GMSL) has risen
by 4 to 8 inches (10 to 20 centimeters).
However, the annual rate of rise over
the past 20 years has been 0.13 inches
(3.2 millimeters) a year, roughly twice
the average speed of the preceding 80
years.
Over the past century, the burning of
fossil fuels and other human and
natural activities has released
enormous amounts of heat-trapping
gases into the atmosphere. These
emissions have caused the Earth's
surface temperature to rise, and the
oceans absorb about 80 percent of this
additional heat.
It is estimated that most of the increase
in sea level will occur as the result of
global warming, which will cause
thermal expansion of the oceans.
Thermal expansion is the seawater
expanding because of the higher
temperature of the water. Since the
oceans absorb heat from the
atmosphere, when the atmosphere
becomes warmer so will the oceans.
Warm seawater has a greater volume
than cold seawater. As the temperature
of the ocean increases so will the total
ocean volume. The increased volume
will cause the level of the water in the
oceans to rise. (COSEE)
The rise in sea levels is linked to three
primary factors, all induced by this
ongoing global climate change, one of
which is: Thermal expansion: When
water heats up, it expands. About half of
the past century's rise in sea level is
attributable to warmer oceans simply
occupying more space. (National
Geographic)
NSF DRL-1316782
Learning Objectives:
1. Students will be able to link thermal expansion of water in the flask to sea-level rise
of our oceans.
2. Students will be able to understand how increased water temperatures change the
volume of water.
3. Students will understand why thermal expansion is a concern for the Tampa Bay
Area.
4. Students will be able to link human activity to sea level rise.
Materials:










500mL (recommended) or 250 mL volumetric flask
Two-hole rubber stopper (Very important!!! Second hole is to allow expanding air to
escape.)
Hot Plate
Thermometer
Marker
Metric ruler
Dropper or Pipette
500ml and 10ml graduated cylinders
Marking pen
Student Record Sheet
Set-up of equipment and close-up of flask with marks made by students showing rise in
water level for every 10°C change in temperature.
NSF DRL-1316782
Procedure:
Discuss Climate Change and Sea-Level Rise in class. Students will be performing an
experiment on how thermal expansion of water contributes to sea level rise.
1. Add water to the flask so that there is some water in its neck (ignore the fill line
stamped/etched onto the flask).
2. Place the thermometer in the flask and be sure to take an accurate first reading.
3. Mark the level on the glass with a marker.
4. Make and Record your initial predictions: What do you think will happen to the
water in the flask as you begin to heat it?
5. Place the flask on the hot plate, and gradually heat the water to no more than 95o C
6. Make a mark on the neck of the flask each time the temperature increases by 10 o C.
7. Allow the flask to cool and pour out the water
8. Use the ruler to measure the height of the water for each mark that you made on the
flask.
9. Refill the flask with cool water to the highest mark
10. Using a dropper (or pipette) and the 10mL graduated cylinder, measure the volume
of water between each mark and record your measurements (remember the top
mark is the water’s volume at the highest temperature).
11. Use the 500mL graduated cylinder to measure the initial volume of water and
record your measurement.
12. Enter your data in the data chart.
13. Make two graphs – one of temperature vs. height, and one of temperature vs.
volume. Plot each of your data points on the graph, then use a ruler or straight edge,
draw the line of best fit. A line of best fit is the line that comes the closest to
connecting the points you plotted (the point should all be near the line).
Lesson Title: Sea Level Rise: Measuring Thermal
Expansion
Initial Predictions: What are all the things that you think will happen to the water in
the flask as you heat it?
_________________________________________________________________________________________________
_________________________________________________________________________________________________
_________________________________________________________________________________________________
_________________________________________________________________________________________________
Data table:
Change in
Temperature
(o C)
0
20
Volume of water in flask
(mL)
542
Change in volume
-Total(mL)
0.0
545
3.0
NSF DRL-1316782
30
50
60
80
546.5
4.5
549.8
7.8
550.9
8.9
553.6
11.6
Increase in volume
(mL)
Change in volume of water vs. change in
temperature
14
12
10
8
6
4
2
0
0
10
20
30
40
50
60
70
80
90
Increase in temperature (degrees Celsius)
Follow-up questions:
1) What happened to the water level in the flask as temperature increased?
_________________________________________________________________________________________________
_________________________________________________________________________________________________
_________________________________________________________________________________________________
_________________________________________________________________________________________________
2) How would you describe the relationship between the rise in temperature and the
rise in the water level?
_________________________________________________________________________________________________
_________________________________________________________________________________________________
_________________________________________________________________________________________________
_________________________________________________________________________________________________
3) Why does the water level in the flask change over time?
_________________________________________________________________________________________________
_________________________________________________________________________________________________
_________________________________________________________________________________________________
_________________________________________________________________________________________________
NSF DRL-1316782
4) How do you think this is related to global warming’s contribution to sea level rise
in our oceans?
_________________________________________________________________________________________________
_________________________________________________________________________________________________
_________________________________________________________________________________________________
_________________________________________________________________________________________________
Relate your data collected to actual Sea Level Rise of the Atlantic Ocean
Using data from the NOAA fact table below, calculate the rise in sea level using the data you
collected and the following procedure
Figure 1 – NOAA Fact Table
Ocean
Area
(km2)
Volume
(km3)
Maximum
Depth
(m)
Average
Depth
(m)
Volume most affected by
GCC
(km3)
Arctic
15,558,000
18,750,000
5567
1205
15,558,000
Atlantic
85,133,000
310,410,900
8486
3646
85,133,000
Indian
70,560,000
264,000,000
7906
3741
70,560,000
Pacific
161,760,000 660,000,000
10803
4080
161,760,000
Procedure to calculate sea level rise
1. First, calculate the slope of the graph to find the increase in volume per degree Celsius in their
flask (don’t forget to include units).
Slope = m =
m=
m=
∆V
∆T
(rise over run)
(8.0mL−0.0)mL
(55℃−0.0)℃
8mL
55℃
≈ 0.15mL/°C
2. Next, find the coefficient of expansion (β) by dividing the slope found in step 1 by the
initial volume of water in the flask. (If you heat any volume of water by one degree, you can
multiply it by this coefficient to find its new volume)
Coefficient of expansion = β =
m
V
NSF DRL-1316782
β=
0.15mL/°C
542mL
≈ 0.00028/°C
3. Use the coefficient of expansion (β) found in step 2 and the data in Figure 1 to find how
much the change in volume (∆V) of the top 1,000m (1.0km) of one of the oceans would
increase per degree, due to thermal expansion
∆V = βV
(where V is the volume most affected by climate change for an ocean)
∆V for the Atlantic Ocean = 85,133,000 km3 × 0.00028/℃
∆Atlantic = 24,000 km3/℃
4. Finally, calculate the sea level rise (∆h) per degree Celsius for the ocean you chose in the
previous step. Divide the change in volume per degree (∆V) by the Area of the ocean listed
in Figure 1.
∆h =
ΔV
A
(Where A is the area of the ocean)
∆Atlantic =
24,000 km3
85,133,000 km2
≈ 0.00028 km/℃ = 0.28 m/℃
Conclusions and Data Analysis:
1) Based on what you know about the Tampa Bay area, how could thermal expansion
impact the lives of the citizens of Tampa Bay?
_________________________________________________________________________________________________
_________________________________________________________________________________________________
_________________________________________________________________________________________________
_________________________________________________________________________________________________
2) Explore this website to see if your predictions were correct:
http://sealevel.climatecentral.org (Interactive map does not work in Internet Explorer)
How will the predicted changes in sea level affect the Tampa Bay area?
One foot? _____________________________________________________________________________________
_________________________________________________________________________________________________
_________________________________________________________________________________________________
Three feet? _____________________________________________________________________________________
_________________________________________________________________________________________________
NSF DRL-1316782
_________________________________________________________________________________________________
Five feet? _____________________________________________________________________________________
_________________________________________________________________________________________________
_________________________________________________________________________________________________
Ten feet? _____________________________________________________________________________________
_________________________________________________________________________________________________
_________________________________________________________________________________________________
3) How can we decrease the threat of sea-level rise of our oceans?
_________________________________________________________________________________________________
_________________________________________________________________________________________________
_________________________________________________________________________________________________
_________________________________________________________________________________________________
4) What personal actions can you take to help slow the rise of sea level?
_________________________________________________________________________________________________
_________________________________________________________________________________________________
_________________________________________________________________________________________________
_________________________________________________________________________________________________
Rise in Volume of water (mL)
5) Test your knowledge of Thermal Expansion and Sea-Level Rise:
http://www.epa.gov/climatechange/students/expeditions/sea-level/index.html
Temperature (o C)
NSF DRL-1316782
NSF DRL-1316782