Tide Detectives: Why Does the Ocean Rise and Fall?

Introduction

Have you ever noticed that the water at the beach sometimes reaches far up the shore and at other times moves farther away?

In this WebQuest, you will become a Tide Detective. Your job is to investigate why ocean tides happen, what causes high and low tides, and how tide information can be useful in real life. The Moon is the main influence on Earth's tides, while the Sun also affects their strength. 

At the end of the activity, you will use what you have learned to help plan a safe and enjoyable beach activity.

Task

Imagine that your class is planning a beach trip. Your teacher wants your group to find out:

  • What causes ocean tides?
  • What is the difference between high tide and low tide?
  • How do the Moon and Sun affect tides?
  • Why is it important to know the tide schedule before going to the beach?

Your final task is to create a one-page infographic or 5-slide presentation entitled:

“Our Guide to Understanding Ocean Tides”

Your output should include:

  1. A simple explanation of what tides are.
  2. The causes of high and low tides.
  3. A labeled drawing showing the Earth, Moon, Sun, and tidal bulges.
  4. One example of actual Philippine tide information.
  5. A short recommendation about why checking tides is useful before a beach activity.

Process

  • Learn the basics.
    Read about what tides are. Identify the meaning of high tide, low tide, and tidal range. NOAA describes tides as long-period ocean waves that appear along coastlines as a regular rise and fall of sea level. 
  • Find out what causes tides.
    Study how the gravitational forces of the Moon and Sun affect Earth's oceans. Pay special attention to why the Moon has the strongest effect on tides. 
  • Study the illustrations.
    Look at NASA's animations showing the Earth, Moon, and tidal bulges. Use these as a guide when making your own simple labeled diagram. 
  • Check real tide information.
    Visit the Philippine tide information provided by NAMRIA. Choose one available tide station or location and record one example of a higher and lower tide level or time. NAMRIA provides predicted hourly tide heights for Philippine locations. 
  • Discuss your findings.
    Answer these questions with your group:
    • Why does the water level change throughout the day?
    • How does the Moon affect the ocean?
    • Why might fishermen, boaters, swimmers, or families going to the beach need tide information?
  • Create your final output.
    Make your infographic or presentation using your own words. Include your diagram, tide information, and recommendation.
  • Check your work.
    Make sure your information is clear, accurate, organized, and based on the resources provided.

Evaluation

Your work will be graded using the following rubric:

4 – Excellent
3 – Good
2 – Developing
1 – Needs Improvement

  1. Understanding of Tides – 4 points
    • 4: Clearly and correctly explains tides, high tide, low tide, and their causes.
    • 3: Explanation is mostly correct with minor missing details.
    • 2: Shows some understanding but has unclear or incorrect information.
    • 1: Explanation is incomplete or mostly incorrect.
  2. Diagram – 4 points
    • 4: Diagram is complete, clear, and correctly labels the Earth, Moon, Sun, and tides.
    • 3: Diagram is understandable with one minor missing detail.
    • 2: Diagram is incomplete or has several unclear labels.
    • 1: Diagram is missing or does not show the concept correctly.
  3. Use of Online Resources – 4 points
    • 4: Uses information from the provided resources and includes actual tide data.
    • 3: Uses the resources but provides limited tide information.
    • 2: Uses only one resource or provides incomplete information.
    • 1: Shows little evidence of using the provided resources.
  4. Organization and Presentation – 4 points
    • 4: Output is clear, organized, easy to understand, and visually appropriate.
    • 3: Output is generally organized with a few unclear parts.
    • 2: Some parts are difficult to follow.
    • 1: Output is poorly organized or incomplete.
  5. Application to Real Life – 4 points
    • 4: Clearly explains why tide information is useful for real-life activities.
    • 3: Gives a reasonable explanation with limited detail.
    • 2: Gives a simple example but does not explain it clearly.
    • 1: Does not connect tides to real-life situations.

Total: 20 points

Conclusion

Through this WebQuest, you learned that ocean tides are not random changes in water level. They are strongly influenced by the gravitational pull of the Moon, with the Sun also contributing to tidal patterns. 

You also learned how to use real tide information and connect a science concept to daily life.

Before finishing, reflect on these questions:

  • What was the most interesting thing you learned about tides?
  • How did using websites, animations, and actual tide data help you understand the lesson?
  • Why is it important to understand tides if you live in or visit a coastal area?