Essential Lab (HOT LAB)
HEATING EARTH’S SURFACE
Which Absorbs and Loses Heat Faster––Land or Water?
Benchmarks:
SC.6.E.7.5 Explain how energy provided by the sun influences global patterns of atmospheric
movement and the temperature differences between air, water, and land.
SC.6.E.7.3 Describe how global patterns such as the jet stream and ocean currents influence
local weather in measurable terms such as temperature, air pressure, wind direction and speed,
and humidity and precipitation.
SC.6.N.1.1 Define a problem from the sixth grade curriculum, use appropriate reference
materials to support scientific understanding, plan and carry out scientific investigation of
various types, such as systemic observations or experiments, identify variables, collect and
organize data, interpret data in charts, tables, and graphics, analyze information, make
predictions, and defend conclusions.
SC.6.N.1.4 Discuss, compare, and negotiate methods used, results obtained, and explanations
among groups of students conducting the same investigation.
Objectives/Purpose:
• Develop and test a hypothesis about how quickly different materials (sand and water)
heat up and cool down when exposed to radiation.
• Explain how the properties of water influence coastal climates.
Background information:
The uneven heating of the Earth’s surface causes weather. When you have differences in air
temperature, the hot air will rise and the cold air will sink. These movements create wind.
Land breezes and sea breezes refer to winds that often occur near an ocean or lake. Both of these
breezes are caused by uneven heating of the Earth’s surface. In this experiment, you will recreate
the conditions under which these breezes form and study their causes.
In Part B of this experiment, you will expose sand and water to a light source representing the
sun.
In this experiment, you will monitor the temperature of the sand and the water and compare their
warming behaviors. Then, you will monitor the temperatures as warm sand and water cool. This
simulates the situation when the sun goes down in the evening. You will then apply your results
to local weather patterns.
Problem: How does the rate at which soil (land) and water (oceans) absorb heat (get warmer) &
lose heat (get cooler) differ?
Hypothesis: Which do you think will heat up faster -- soil or water? Which do you think will
cool down faster -- soil or water? Record your hypothesis, below:
If we measure the rate of heat, then __________ will warm up faster than ___________, because
_____________________________________________________________________________.
If we measure the rate of heat loss, then _____________ will cool faster than ______________,
because_______________________________________________________________________.
Essential Lab (HOT LAB)
Variables:
Independent (manipulated/testing variable): __________________________________________
Dependent (responding/outcome variable): __________________________________________
Controlled (constants): __________________________________________________________
Materials:
• 2 250-mL beakers
• ruler
• dry sand
• 2 flat wooden sticks
• tap water
• 2 thermometers
• ring stand
• light source
• 2 different-colored pencils (brown and blue)
Procedures:
Part A: Preparing for the Experiment
1. Pour 200 mL of dry sand into one of the beakers. Pour 200 mL of water into the other beaker.
2. Place the lamp approximately 10 cm from the beakers. Make sure that both beakers are equal
distance from the lamp and that both receive light at the same angle.
Part B: Heating the Beakers
1. Use the Data Table to record your measurements.
2. Record the starting temperature of the sand (land) : _____°C and water (ocean): _____°C
CAUTION: DO NOT TOUCH THE LIGHT SOURCE OR THE BEAKERS.
3. Turn on the lamp. Read the temperature (°C) of the sand and water every minute for 15
minutes. Record the temperatures in the Light On (LEFT) column of the data table.
4. Turn off the lamp. Read the temperature (°C) of the sand and water for another 15 minutes.
Record the temperatures in the Light Off (RIGHT) column of the data table.
DATA TABLE
TEMPERATURE WITH LIGHT ON
TEMPERATURE WITH LIGHT OFF
(°F)
(°F)
Time (min.)
Land
Water
Time (min.)
Land
Water
0
16
1
17
2
18
3
19
4
20
5
21
6
22
7
23
8
24
9
25
10
26
11
27
12
28
13
29
14
30
15
Essential Lab (HOT LAB)
5. On the graph, shown below, create two line graphs to show the data for the temperature
change in land and water over time. You will draw both lines on the same graph. Make a
brown line to show temperature change in land and make a blue line to show temperature
change in water.
Temperature (°C)
TITLE: ____________________________________________________
68
66
64
62
60
58
56
54
52
50
48
46
44
42
40
38
36
34
32
30
28
26
24
22
20
0
1
2
3
4
5 6
7
8
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29
Time (minutes)
PROCESSING THE DATA
1. Calculate the total change in temperature for each material.
Sand: heated by ___________ degrees in 15 min.; cooled by __________ degrees in 15 min.
Water: heated by ___________ degrees in 15 min.; cooled by __________ degrees in 15 min.
2. Based on your data:
Which material was heated faster by the “sun”? _______________________________________
Which material cooled faster when the light was shut off? _______________________________
Essential Lab (HOT LAB)
Part I
1. As surface materials are warmed by the sun, they in turn warm the air above them. As the sun
shines, is the air above the sand or the water warmer?
______________________________________________________________________
2. Use Figure 3 to complete the following tasks.
a. Based on your answer to Question 3 and knowing that warm air rises and cool air
sinks, place arrowheads on the two vertical lines in Figure 3 indicating the general
direction of air movement over the sand and the water on a sunny day.
b. The two vertical arrows you have drawn form the basis of a circular convection
current.
Now draw two horizontal arrows that complete the path of this convection current.
Figure 3: A sunny day at the beach
5. Imagine yourself standing on the beach in the diagram above. According to the arrows you
drew, where would the breeze be coming from? ________________. Is this a sea breeze or a
land breeze? __________________________.
Part II
6. According to your data, which material cooled faster, the water or the sand? ______________
7. As surface materials cool, they in turn cool the air above them. After the sun goes down and
the warm surfaces cool, is the air above the sand or the water warmer? _____________________
8. Use Figure 4 (on the next page) to complete the following tasks.
a. Based on your answer to Question 7 and knowing that warm air rises and cool air
sinks, place arrowheads on the two vertical lines in the diagram indicating the general
direction of air movement over the sand and the water after the sun goes down.
b. The two vertical arrows you have drawn form the basis of a circular convection
current.
Essential Lab (HOT LAB)
Draw two horizontal arrows that complete the path of this convection current.
Figure 4: Night time at the beach
Imagine yourself standing on the beach in the diagram above. According to the arrows you drew,
where would the breeze be coming from? _______________________. Is this a sea breeze or a
land breeze? _____________________.
9. Fill in the blanks.
On a sunny day at the beach, the wind will usually blow from the _______________ to the
_______________. This is called a _______________ breeze. As evening falls, the wind will
shift and blow from the _______________ to the _______________. This is called a
_______________ breeze.
CLAIM, EVIDENCE, and REASONING CONCLUSION:
Using the following prompt, write a Claim-Evidence-Reasoning statement using your lab data:
Imagine two areas of the planet that are exactly the same except that one contains a large body of
water. Based on the results from the lab investigation, which area will experience a wider range
in temperature throughout the year?