Lesson 4: Tides and Gravitational Interactions in the Sun–Earth–Moon System

-What causes ocean tides on Earth?

-How do the Moon and Sun influence Earth’s tides?

-Why do high and low tides occur at predictable times?

-What is the difference between spring tides and neap tides?

-How does the relative position of the Sun, Earth, and Moon affect tidal range?

-How can models and data be used to predict tidal patterns?

-Why do different locations on Earth experience different tidal ranges and timing?

Tide

High tide

Low tide

Gravitational force

Tidal bulge

Spring tide

Neap tide

Centripetal force

Orbit

Alignment

Lunar gravity

Solar gravity

Tidal range

HS-PS2-4 – Use Newton’s laws and gravitational interactions to predict and explain motion and interactions within the Sun–Earth–Moon system.

HS-ESS1-2 – Analyze data to describe how the Moon’s orbit and gravitational effects produce observable patterns such as tides.

NGSS Crosscutting Concepts

-Patterns

-Cause and Effect

-Systems and System Models

-Scale, Proportion, and Quantity

Students will analyze tidal charts and graphs to identify predictable patterns in ocean tides over time.

Students will interpret diagrams showing gravitational interactions to explain how the Moon and Sun influence tidal behavior.

Students will construct explanations using evidence to describe how alignment of the Sun, Earth, and Moon affects tidal range and frequency.

Students will investigate how gravitational forces between the Earth, Moon, and Sun create ocean tides and influence their timing and magnitude. Through modeling, data analysis, and simulations, students will examine how tidal bulges form and how alignment affects spring and neap tides.

Activities may include:
-Modeling tides using Earth-Moon-Sun systems and flexible materials or simulations
-Analyzing real tidal charts from coastal locations
-Comparing spring and neap tide conditions using diagrams
-Using simulations to predict tidal patterns over time
-Explaining gravitational interactions using Newton’s laws in conceptual form

Purpose: Develop understanding of how gravitational interactions produce predictable patterns in Earth’s oceans and strengthen students’ ability to connect physical forces to observable Earth systems.

DOK Level: 3 – Strategic Thinking / Reasoning (analyzing patterns, applying models, and explaining gravitational relationships)

Students connect tides to real-world coastal phenomena such as fishing, boating, erosion, and coastal safety.

Students explore how coastal communities and cultures have historically used tidal knowledge for navigation, trade, and survival.

Connections to modern applications such as harbor management, renewable tidal energy, and coastal engineering.

Students may think tides are caused primarily by the Sun rather than the Moon.

Students may believe tides are caused by the Moon “pulling water up” on only one side of Earth.

Students may assume there is only one high tide and one low tide per day everywhere.

Students may think tides are caused by weather or wind rather than gravitational forces.

Students may struggle to understand why tidal bulges occur on both sides of Earth simultaneously.

-Step-by-step modeling of tidal bulges using diagrams and simulations

-Visual supports showing gravitational interactions and alignment

-Graphing tidal data with guided interpretation

-Chunked explanations of spring vs. neap tides

-Partner or group analysis of real tidal charts

-Use of sentence frames for explaining cause-and-effect relationships

-Formative checks during tide modeling and simulations

-Quizzes on tidal vocabulary and concepts

-Graph analysis of real tidal data sets

-Constructed-response explanations of how tides form

-Diagram labeling of Earth–Moon–Sun tidal interactions

-Exit tickets predicting tide patterns based on lunar phase and alignment

-Earth–Moon–Sun simulation tools or digital models

-Tidal charts from NOAA or similar data sources

-Interactive simulations of gravitational interactions and tides

-Diagrams of tidal bulges and alignment scenarios

-Graphing worksheets for tide prediction

-Visual media explaining coastal tides and ocean behavior