LIFE Gulf-To-Bay– Pinellas County: NOAA Bay Watershed Education and Training (B-WET) Field Experience II (Weedon Island)
The Tides They Are A Changin’
Revised: 2013.06.06
Teacher’s Guide
Body of Knowledge:
Earth-Space Science
Big Idea (benchmark):
Earth in Space and Time (SC.8.E.5.9)
Summary:
Students will investigate indicators of tidal change.
Objective(s):
After completing the field lab, students will be able to:
1. Explain the planetary forces that cause tides
2. Explain which planetary body plays a more significant role in causing
tides and why this happens
3. Identify at least 2 natural indicators of tidal ranges
Ecosystem(s):
Any open area fringed with mangroves and with access to a tidally influenced
water body
Equipment:
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GPS
Measuring sticks
Nylon Line
4 x 1 meter stakes
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Index Cards and Tacks
Permanent Marker
Survey Tape Measure

Labels/Name tags for earth,
sun, moon or inflatable
representations of each
 Line Level
Background (Pre-field Classroom Activity):
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Equipment Training: GPS
Vocabulary: Tides, Tidal Range, Gravity, Wrack Line, Neap Tide, Spring Tide, Diurnal, Semi-Diurnal,
Mixed Semi-Diurnal
Reference material: http://estuaries.noaa.gov/Teachers/water.aspx;
http://oceanservice.noaa.gov/education/lessons/ups_downs.html
Preparation: Investigate tidal cycles at Weedon Island Preserve. Are the tides Diurnal, Semi-Diurnal,
Mixed Semi-Diurnal?
Tides are created by the gravitational pull of both the sun and the moon as well as the rotation of the earth while in orbit around
the sun. While the sun is a much larger celestial body, its influence is less than that of the moon because the moon is much
closer to the earth. This lab will investigate physical and biological indicators of the tides as well as how local organisms have
adapted to the daily changing water levels.
Procedures (Engage; Explore; Explain; Elaborate; Evaluate):
1. Ask students what does “Tide” mean – what is a high tide, what is a low tide? What causes tides? Does anything
else influence tides? How many tides does Weedon Island have during a 24 hour period?
2. Engage: Demonstrate how tides work using students to represent a high tide (use laminated signs to label each
celestial body). Have the chaperone/teacher stand at a point where the students can rotate around him/her. Have 4
students stand next to teacher’s left shoulder. Have 4 students stand next to teacher’s right shoulder. Have 2 students
stand in front of the teacher and 2 students stand behind the teacher. 1 additional student will be the sun and should
stand 10 feet away, directly in line with teacher’s left shoulder. Final student will be the moon and should stand 5 feet
away, directly in line with teacher’s right shoulder. Explain how this simple example shows how the sun and moon’s
gravity pulls water into tidal bulges in line with these 2 celestial bodies. Have the sun and moon move around the
teacher and have the students/tides move as a simple tide model. Discuss spring and neap tides then
practice/demonstrate with students.
3. Explore: Bring students down to water’s edge. Have them look for signs of tidal influence in the area.
4. Have the students place a stake with the inside edge marking the tide level. Have a student record the date and
time on an index card and tack it to the stake. Subsequent groups will put their own stakes in and record their
information. As the day progresses, later groups should be able to see a change in water level as indicated by
difference in stake locations. Subsequent groups should measure the distance between the inside edge of the original
tide marker and the inside edge of their marker to measure the change in tide. Record the data. Data should be shared
between groups in the classroom as a follow up activity.
Office of Environmental Education - Florida Department of Environmental Protection
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LIFE Gulf-To-Bay– Pinellas County: NOAA Bay Watershed Education and Training (B-WET) Field Experience II (Weedon Island)
General Information:
Revised: 2013.06.06
Student Data Sheet
Full Name:
Date:
Teacher:
Time:
Latitude:
Longitude:
Student Hypothesis, Explanation, or Prediction:
If Tampa Bay water levels at Weedon Island slowly change due to the tides, then I (check one: __will __will not)
be able to tell what is currently happening with tide levels because…
Field Observations/Measurements:
Item
Measurement
Current Time
Time of previous group
(see closest pre-existing
stake)
Horizontal distance (in cm)
between current tide level
and previous
Distance (in cm) from
wrack line to current stake
Vertical change (in cm) in
water level from current to
previous group
Based on my observations
the tide is (rising or falling)
Based on Tide Chart (GPS
or phone App) the tide is
(rising or falling).
OPTIONAL: Measure
Percent Slope (Rise of Run)
from wrack line to first tide
Office of Environmental Education - Florida Department of Environmental Protection
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LIFE Gulf-To-Bay– Pinellas County: NOAA Bay Watershed Education and Training (B-WET) Field Experience II (Weedon Island)
The Tides They Are A Changin’
Revised: 2013.06.06
Assessment Questions
1. What was the distance between the previous group’s stake and your stake? How many minutes elapsed between
the two measurements?
2. Calculate how many centimeters per minute the tide moved in or out during this period.
3. Did the data support your hypothesis? Why or why not?
4. Under which conditions, from the drawings below, would the high and low tide be more extreme? Why?
Drawing #1
Drawing #2
5. Have humans adapted to changing tides in the same way that plants and animals have adapted over time?
Explain
6. Based on the results of this lab, write a question for something you’d like to learn more about related to tides.
Office of Environmental Education - Florida Department of Environmental Protection
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LIFE Gulf-To-Bay– Pinellas County: NOAA Bay Watershed Education and Training (B-WET) Field Experience II (Weedon Island)
The Tides They Are A Changin’
Revised: 2013.06.06
Writing Prompt
Imagine you are the captain of a sailing ship/cargo ship. At what times during your journey would it be most
important for you to know the level of the tides? Why? What might happen if you read the tide chart wrong?
Office of Environmental Education - Florida Department of Environmental Protection
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