Relating Tides to the Moon Phases

By Laura Hospitál on Feb 19, 2016

We just covered the phases of the Moon, with tides as our next topic of study. It occurred to me that the http://www.perkinselearning.org/accessible-science/phases-moon-active-model model would work well to explain this concept as well as how higher tidal ranges occur during spring tides (New Moon and Full Moon) and lower tidal ranges occur during Neap Tide (First Quarter and Third Quarter).  This served a double purpose, both clarifying the concepts of spring tides and neap tides, as well as reinforcing students' understanding of the phases of the Moon. 

Please read over this procedure prior to completing the activity.  I have included in this procedure all of the questions to add for the added content.

If an APH globe is not available, the student themselves can represent the earth and the moon.  Please see variations. 

Preparation:

  • Place the stationary chair approximately 4' from the fan and the rolling chair approximately 3' from the fan between the fan and the rolling chair.
  • Place the model of the Earth on the stationary chair.
  • Blow up the balloon to approximately 1/4 the diameter of the Earth. 

Materials

Procedure

After initial instruction on spring tides and neap tides, students are proceeding through the phases of the Moon as per http://www.perkinselearning.org/accessible-science/phases-moon-active-model

Add the following questions about the tides to each phase described.  Describe the phase of the Moon, but do not focus on the amount of the Moon that is visible as you proceed through the phases.  Instead focus on the configuration of the Sun, Earth, and Moon as it relates to the tides.

1. New Moon

  • Ask:  "What position are the Sun, Moon and Earth in?"  lined up 
  • Say:  "This will cause the gravitational effect of the Sun and the Moon on the Earth to add together."
  • Ask:  "What effect will this have on tidal ranges?"  They will increase.
  • Ask:  "Why will this increase the tidal ranges?"  Student should repeat that the gravitational effect will be added together
  • Ask:  "What do we call the tides with the largest tidal ranges that would occur at this time?"  Spring Tides

2. Proceed to First Quarter

  • Ask:  "What position are the Sun, Moon and Earth in?"  at right angles (90 degree angle)
  • Say:  "This will NOT cause the gravitational effect of the Sun and the Moon on the Earth to add together."
  • Ask:  "What effect will this have on tidal ranges?"  They will be less.
  • Ask:  "Why will this decrease the tidal ranges?"  Student should repeat that the gravitational effect will NOT be added together because the Sun, Moon, and Earth are at right angles.
  • Ask:  "What do we call the tides with the smallest tidal ranges that would occur at this time?"  Neap Tides

3. Proceed to Full Moon 

  • Ask:  "What position are the Sun, Moon and Earth in?"  lined up 
  • Say:  "This will cause the gravitational effect of the Sun and the Moon on the Earth to add together."
  • Ask:  "What effect will this have on tidal ranges?"  They will increase.
  • Ask:  "Why will this increase the tidal ranges?"  Student should repeat that the gravitational effect will be added together
  • Ask:  "What do we call the tides with the largest tidal ranges that would occur at this time?"  Spring Tides

4. Proceed to Third Quarter

  • Ask:  "What position are the Sun, Moon and Earth in?"  at right angles (90 degree angle)
  • Say:  "This will NOT cause the gravitational effect of the Sun and the Moon on the Earth to add together."
  • Ask:  "What affect will this have on tidal ranges?"  They will be less.
  • Ask:  "Why will this decrease the tidal ranges?"  Student should repeat that the gravitational effect will NOT be added together because the Sun, Moon, and Earth are at right angles.
  • Ask:  "What do we call the tides with the smalles tidal ranges that would occur at this time?"  Neap Tides

Closure:

Have the student describe the tides related to the phases of the Moon while using a tactile drawing or model.  The student should begin at New Moon and procedd through the phases.  The tactile drawing from the APH Astronomy kit of the phases of the Moon is well-made. http://www.perkinselearning.org/accessible-science/aph-sense-science-astronomy-kit     If time allows, have the student use Jim Clark's model stationary model http://www.perkinselearning.org/accessible-science/sun-earth-moon-system-model to also show his/her understanding of how the phases of the Moon and tidal ranges are related.   

Variations

  • This activity also works well with one student representing the Earth and a second student representing the Moon. In this case, no chairs are needed to hold the Earth and the Moon (student) would not need to roll around on a chair, but would walk around the Earth (the 2nd student).  

NGSS Standards:

Grade 5 - Space Systems

PS2.B: Types of Interactions
The gravitational force of Earth acting on an object near Earth’s surface pulls that object toward the planet’s center. (5-PS2-1)
 
ESS1.B: Earth and the Solar System
The orbits of Earth around the sun and of the moon around Earth, together with the rotation of Earth about an axis between its North and South poles, cause observable patterns. These include day and night; daily changes in the length and direction of shadows; and different positions of the sun, moon, and stars at different times of the day, month, and year. (5-ESS1-2)

Middle School - Space Systems

ESS1.A: The Universe and Its Stars
Patterns of the apparent motion of the sun, the moon, and stars in the sky can be observed, described, predicted, and explained with models. (MS-ESS1-1)

High School: Forces and Interactions

PS2.B: Types of Interactions
Newton’s law of universal gravitation and Coulomb’s law provide the mathematical models to describe and predict the effects of gravitational and electrostatic forces between distant objects. (HS-PS2-4)
 
Forces at a distance are explained by fields (gravitational, electric, and magnetic) permeating space that can transfer energy through space. Magnets or electric currents cause magnetic fields; electric charges or changing magnetic fields cause electric fields. (HS-PS2- 4),(HS-PS2-5)
 
Collage of relating tides to moon phases