Seasons, Eclipses and Tides

 

Drew Keller,  Educator, MathScience Innovation Center

 

Developed with funding from the MathScience Innovation Center

 

 

Major

Understanding

Students will investigate and understand the relationship of the Earth’s tilt and the seasons, the relationship of the Moon’s position for eclipses, and the cause of tides

 

Grade/Subject

Science 6,  Earth Science

 

Objectives

Use a model to explain that changes in the angle at which light from the sun strikes Earth, and the length of daylight, determine seasonal differences in the amount of energy received.

 

 

Explain how the relationship between the tilt of Earth's axis and its yearly orbit around the sun produces the seasons.

 

 

Identify factors creating solar and lunar eclipses.

 

 

Describe the role of the Moon in generating ocean tides.

 

 

Explain some of the different types of ocean tides the Moon helps generate.

 

Time

Introduction with PowerPoint S.E.T.

5 min

 

 

Seasons Activity Intro and cont. PowerPoint S.E.T.

10 min

 

 

Seasons Lab Activity

20 min

 

 

Eclipses Intro and cont. PowerPoint S.E.T.

5 min

 

 

Solar Eclipse Demonstration

10 min

 

 

Tides Activity Intro and cont. PowerPoint S.E.T.

10 min

 

 

Tides Lab Activity

20 min

 

 

Review

10 min

 

 

Materials

For the class:
PowerPoint S.E.T.
Projection Screen
LCD Projector
Computer speakers
Laptop computer with internet connection

 

For each student:
Solar Motion Model (Made by The Science Source)
Seasons Activity Worksheet
Eclipses (tennis ball)
1 Tides Gages Diagram (In Transparency)

Tides Activity Worksheets

 

State and National

Correlations

Virginia Standards of Learning: 6 Science (6.8); Earth Science (ES.4).

National Science Education Standards: Content Standard A (Science as Inquiry); Content Standard D (Earth and Space Science); Content Standard E (Science and Technology)

 

Instructional

Strategies

1.         Anticipatory Set

a.     Start with displaying the title slide in PowerPoint S.E.T. of the lesson ‘Seasons, Eclipses and Tides’. Discuss how many people have misconceptions about basic astronomy. But before you show a video of college students revealing basic misconceptions about astronomy you want to see if your student’s have any misconceptions about Seasons. Ask the students to describe in their own words what a misconception is.

 

2.    Seasons Intro and PowerPoint S.E.T. Instruction

a.     Ask your student’s to quietly write down in one or two sentences their understanding of why we experience seasons. Show the Power point slide with this question visible. Explain to them you will not call on anyone to read their answer but rather want them to record their understanding prior to beginning the activity. Students will likely to pay close attention if they have any misconceptions about the cause of the seasons before beginning the first activity on seasons. After a few minutes ask for a few volunteers to share their answer but do not comment on whether they are right or wrong. This can be a difficult question for students at this age to explain in their own words so if no one volunteer just move to the next step

 

b.    Show the first few minutes of the ‘Private Universe’ video which shows Harvard graduates answering this same question. This video is available free through an internet connection from Annenberg Media. Click on the ‘Video on Demand’  link to view the video. If this is your first visit to the site you will need to sign up to gain access. Questions to ask the students after watching the Harvard graduates responses:

 

How many out of those interview revealed misconceptions about the cause of the seasons or phases of the moon? Answer: 21 out of the 23 revealed misconceptions

 

Did any of those interviewed have a similar response to what you wrote down on paper?

 

After watching the video how would you best characterize the earth orbit? Nearly perfect circle or elongated ellipse? Answer: Nearly perfect orbit.

 

Does the changing distance of the Earth from the Sun greatly influence why we have seasons? Answer: Changing distance has virtually no effect the Earth’s changing seasons.

 

More than likely several of your students will have some misconceptions regarding the cause of the seasons. To aid into a more scientific understanding of the cause of the seasons you will have the students use the Solar Motion Device. See Solar Motion Device Demonstration Tips. You will to have constructed the device prior to beginning this activity.

 

Note: If you do not want to purchase a class set of 24 you can construct your own. Lawrence Hall of Science provides instructions and a template. Click here to be taken to their PDF of the Solar Motion Device.

 

3.    Seasons Lab Activity

       Hand out the Seasons Activity Worksheet. The students should be able to complete this activity in about 15 to 20 minutes. Allow some time for review near the end to reinforce that seasons are an effect of the angle of sunlight that strikes the Earth and the length of daylight. These two factors are driven by the Earth’s axis being tilted.

 

4.    Eclipse Intro and PowerPoint S.E.T. Instructions

a.     Students can reveal misconceptions about eclipses as well. For an intro to this short activity show the slide of a picture taken of the Sun and Moon from Earth. Both which appear to be the same size. Ask the student a few of the following questions:

 

Which image is of the Sun taken through a sun filter? Answer: The one on the left.

 

Do they appear to be the same size next to each other? Answer: Yes they appear to be the same size.

 

Are they the same size? Answer: No the Sun is much larger.

 

Why do you think they appear to be the same size? Answer: The Moon is much closer to the Earth.

 

b.    Briefly go over the Earth’s orbit and the Moon’s orbit. Ask the student about how long does it takes for the Moon to orbit the Earth. Model this using three tennis balls. The answer is about 4 weeks.

 

c.     Demonstrate that as the Moon’s orbit passes between the Earth and the Sun the Moon’s shadow would be cast on the Earth. A common misconception would be that this shadow is cast on the Earth about every four weeks. Taking into account that your simple model is not to scale explain to the students that if they were standing (On Earth of course) in this shadow when they looked up what would they see.

 

5.    Solar Eclipse Demonstration

a.     Display the enlarged Sun in the Power point slide show.

 

b.    Give each student a tennis ball and tell them that this represents the Moon. Together you will demonstrate with them the three basic types of Solar eclipses. Below you will find instructions on demonstrating each of the three solar eclipses.

 

To demonstrate a total solar eclipse; have the students hold their tennis ball at arm’s length and close one eye. Then tell the students to position the tennis ball so that it just covers the Sun completely which is displayed on the projection screen. This would represent to a viewer on Earth a total solar eclipse, where the Moon completely blocks out the sunlight.

 

To demonstrate a partial eclipse have the students move the tennis ball slightly to the left or right where some of the Sun displayed on the projection screen is visible. This would represent a partial eclipse.

 

To demonstrate a annular eclipse instruct the students to cover the Sun displayed on the screen back up as demonstrated in a total solar eclipse. Then have the students slowly move the tennis ball toward the screen so they can see the outer part of the Sun. The Moons distance from Earth is not constant. This is referred to as perigee (closest) and apogee (farthest).  When the Moon is at or near perigee during an solar eclipse viewers will often experience not a total solar eclipse but an annular eclipse.

 

c.     After reviewing reinforce what the students have demonstrated by viewing the Power point slide that show images of the three different types of solar eclipses. Ask students to identify each eclipse.

 

d.    Lunar Eclipses are evident when the Earth is between the Moon and the Sun. The Earth’s shadow is cast on the visible side of the Moon. Though use of the tennis balls does not lend itself to demonstrating this type of eclipse called a lunar eclipse you can still go over with the students. The most useful computer program that will aid in students understanding of this difficult to grasp concept we have found is River Scientific Inc. New Moon.

 

6.    Tides Intro and PowerPoint S.E.T. Instructions

a.     Understanding the driving force behind tides on Earth is difficult for students to comprehend. Explain that they are going to do a lab activity that will explain the different types of tides the Moon helps generate. Show the slide that displays a tidal chart for a given location on the Earth and ask what force allowed the water level to rise and fall in a 24 hour period. Then display the slide with three tidal charts. Each chart was taken from a tidal station located at different latitudes. Ask the students to think about why each location experienced a different type of tide.

b.    Hand out the first two pages of the Tides Activity Worksheet along with a tidal gauge transparency. Students should be looking at the second page titled ‘Earth Cross-Sections’. Use the slides in the Power Point presentation to help students conceptualize where each cross-section on the Earth is made.

 

c.     Demonstrate how the tidal gage transparency works for measuring the sea level for a location on Earth over one tidal period. Use the slides provided in the Power point to aid in your demonstration.

 

7.    Tidal Lab Activity

a.     Hand out the final two pages of the Tides Activity Worksheet (Equatorial Tide Diagram and Tropic Tide Diagram) to each student. Use the slides provided in the Power point that will help students understand how to plot points for each of the cross sections.

 

b.    Students should answer the questions (#1 through #7) on the Tides Activity Worksheet. Allow some time for review at the end of this lab activity.

 

Practice

1.      Seasons (outside activity)

2.      Eclipses

3.      Tides

 

Closure

Review each of the objectives with the students. Be sure to cover each of the three topics discussed: Seasons, eclipse and tides

 

Seasons

 

Eclipses

 

Tides

 

 

Extensions

Encourage your students to explore further by trying theses other activities

 

1.         Seasons


2.         Eclipses

 

3.         Tides

 

Assessment

Sample items are provided for use in checking students’ understanding.

Paper Pencil Test: Seasons, Eclipses and Tides Assessment

 

Performance Task: Using the Solar Motion Device Outside

 

The following table shows how the assessment items are related to specific objectives.

 

Objective

Paper-Pencil

Test

Product/

Performance

Use a model to explain that changes in the angle at which light from the sun strikes Earth, and the length of daylight, determine seasonal differences in the amount of energy received.

1,2

Performance Task

Explain how the relationship between the tilt of Earth's axis and its yearly orbit around the sun produces the seasons.

3

 

Identify factors creating solar and lunar eclipses.

4,5,6

 

Describe the role of the Moon in generating ocean tides.

7,8

 

Explain some of the different types of ocean tides the Moon helps generate.

9,10

 

 

Teaching Tips

Materials and Supplies

 

Seasons Activity Worksheet Answer Key

 

Tides Activity Worksheet Answer Key

 

Seasons Extension Activity Worksheet Answers

 

Paper Pencil Test: Seasons, Eclipses and Tides Assessment

 

Performance Task: Using the Solar Motion Device Outside

 

 

References

MathScience Innovation Center
Information on educational programs available to students, teachers and school divisions and procedures for registering for programs.
http://msinnovation.info

MathScience Innovation Center: On-Line Educational Programs
Learn through on-line virtual classrooms, web-based lessons and on-line courses. Access proven lesson plans and instructional modules.
http://mathinscience.info

NOAA NOS Tides and Water Levels
NOAA's National Ocean Service has three sections available devoted to learning about tides and water levels: an online tutorial, an educational roadmap to resources, and formal lesson plans.
http://www.oceanservice.noaa.gov/education/kits/tides/welcome.html  

Tides Online NOAA/NOS/CO-OP
The Tides Online page provides users with immediate graphical and tabular water level and meteorological data from NOS water level stations located along the projected path of severe storms such as hurricanes
http://tidesonline.nos.noaa.gov/