Tides
Overview
Students explore tides through discussion, a NOAA tutorial, and group activities to understand their causes, predictability, and connection to waves and currents.
Focus Questions
- What are tides?
- What causes the tides?
- How are waves and tides related?
Enduring Understandings
- Physical changes in the aquatic environment occur on a daily, seasonal, and long-term basis.
- Weather systems and ocean systems have major influences on one another and the dynamics of matter and energy.
- Science and technology can be used to detect and solve problems.
Engage
10 Minutes
Ask the students what they know about tides, and begin a KWL chart. Explain that you will be looking for the answers to these questions, as well as other questions they raise about tides:
How are waves and tides related? What are tides? What causes tides? What does wave energy have to do with tidal motion?
Explore
20 Minutes
Project the NOAA Tide tutorial and work through it with students, providing guidance and discussing the concepts. Be sure to show the animation. (The reading level of the tutorial is high for most middle school students, so this may not work well as an independent assignment.)
Explain
30 Minutes
Have students work in groups of 2-4 to discuss the important ideas, facts, and answers to the focus questions. They should work together to choose a format and create a graphic organizer that shows the important ideas, facts, and answers to the questions: What are tides? What causes the tides? How are waves and tides related? Each student should glue a copy of the graphic organizer into their science notebook.
Have groups share their graphic organizers, and complete the KWL chart about tides as a class. Students should add any ideas or facts they may have missed to their own organizer in their science notebook.
Important concepts listed should include the following:
• Tides are regular and predictable.
• Tides are very long-period waves that start in the ocean because of the forces of gravity from the sun and moon, and move toward coastlines.
• Tides appear on coastlines as the regular rise and fall of the sea surface. Low tide on shore coincides with the wave trough, and high tide corresponds with the wave crest.
• Incoming (flood) and outgoing (ebb) tides can create horizontal movement of water or currents. Tide currents can be strong in entrances, inlets, and narrow straits. They are weak in the open ocean.
Elaborate
This activity is expanded on in the following activity, Tide Patterns.
Curricular Connections
This investigation can provides connections to math through graphing activities and measurements and calculations of wave frequencies and periods. The many opportunities to write, discuss, and present information to the class provide connections to language arts.
Ideas for adapting to different local environment or context. Investigate local cultural traditions and knowledge related to tides.
Teacher Needs
Teacher Prep
1½ to 2 hours to read all of the materials, make copies, set up computer/projector, gather materials and set up/practice lab activities, find and print tide data.
Materials List
Student Handouts
Science notebooks
Facility/Equipment Requirements
Computer connected to Internet, with projector.
Student Needs
Prior Knowledge
Students should have some experience with energy and energy transfer.
Vocabulary
Amplitude, aphelion, apogee, crest, diurnal tides, ebb, flood, frequency, marigram, mixed semi-diurnal tides, neap tides, perigee, perihelion, semi-diurnal tides, spring tides, tidal current, tidal range, tide, trough, tsunami, vertical circle, wave, wave height, wavelength, wave period
Standards
Science GLEs Addressed
- 6th grade: SA1.1
- 7th grade: SA1.1, SB4.3
- 8th grade: SA1.1