• Assess students’ understanding of tides during the modeling activity and discussion. During the Tracking the Tides graphing activity, assess students’ understanding of the tidal cycle and ability to interpret the data based on their data predictions.
• Collect and assess the Tides worksheet (S-7-9-3_Tides and KEY.docx).
• Assess students’ understanding of Moon phases during the Moon Modeling activity, based on their diagrams, the three-dimensional model, and explanation during the role-playing.
• Assess students’ understanding of lunar eclipses from their participation in the modeling activity and the individual diagrams that they create.

Day 1: Tides

In advance, prepare large name tags that say “Earth,” “Moon,” “Sun,” and “Gravity” (make two Gravity signs). Tie one end of two 18-inch pieces of strings to two safety pins. It may be helpful to make overhead transparencies of the two-column notes resource (S-7-9-3_Tides Notes and KEY.docx).

Use a document camera to show students the image on “What Happened to the Sand Castles?” (S-7-9-3_Sand Castles.docx). They will probably know that the tide came in and washed away the sand castles. Ask them to share any personal experiences with the tide coming in or going out when they were at the beach.

Demonstration

Tell students that the tides are affected by the motion of the Moon. Demonstrate how the Moon affects the tides, using students for the model. Select students to stand in the front of the room to symbolize the Earth, Moon, and Sun, and two students to represent the force of gravity. Pin the safety pins with string attached to each side of the “Earth’s” shirt (pin them on a hem). The shirt represents the Earth’s oceans. The “gravity” students will use the strings to demonstrate the force of gravity.

Define spring tides as the tides that occur near the new or full moon, when the Moon and Sun are in alignment, causing the greatest ranges between high and low tide. To demonstrate a spring tide, have the “Moon” stand between the “Sun” and the “Earth.” See the Tides and Moon Phases Diagram below for relative positions of the Earth, Moon, and Sun. Have “gravity” students tug VERY gently on the strings in the directions towards and away from the “Moon.” As the models demonstrate, ask students to identify where the high and low tides would be on the Earth. Have students write spring tide in their notes; draw the positions of the Earth, Moon, and Sun; and label the pull of gravity on the ocean tides.

Define neap tides as the tides that happen near the first quarter and third quarter moons, causing the minimum difference between high and low tide. To demonstrate a neap tide, have the “Sun” and “Moon” stand perpendicular to the “Earth” and have the “Earth” face the “Moon.” Then, have the “gravity” students tug VERY gently on the strings in the direction of the “Moon” and directly opposite the “Moon” to demonstrate how gravity creates tidal bulges. Ask the rest of the class to identify where high and low tides would happen on the Earth. Have students write neap tide in their notes; draw the positions of the Earth, Moon, and Sun; and label the pull of gravity on the ocean tides.

Tides and Moon Phases Diagram

Source: http://www.atlantickayaktours.com/images/drawings/Navigation/SpringNeap-Tides-color.gif

Neap tides occur on the first quarter and third quarter moons. Spring tides occur on the new moon and full moon.

Hand out copies of the Tides two-column notes (S-7-9-3_Tides Notes and KEY.docx). Guide students through completing the two-column notes worksheet on tides. Use the Tides and Moon Phases Diagram to assist with explaining the tides (S-7-9-3_Tides and Moon Phases Diagram.docx).

Ask, “Why might it be important for people to know whether the tides will be high or low at specific times?” (Patterns in the tides are important to fishermen, boaters, oceanographers, marine biologists, vacationers, and meteorologists. For example, meteorologists tracking hurricanes are able to gauge the potential impact of a hurricane on a shoreline in terms of water level by knowing the phase of the moon at the time of the storm and the times of high tide and low tide.)

Tell students that many newspapers in coastal regions have charts that show the high and low tides. Note: Most places in the ocean usually have two high tides and two low tides each day (semidiurnal tide), but some locations have only one high and one low tide each day (diurnal tide).

Hand out graph paper and copies of Tracking the Tides (S-7-9-3_Tracking the Tides.docx). Show students how to read the tidal chart and guide them through making a graph of the tides. Students may need assistance with labeling the increments on the x- and y-axis. As a class, develop predictions to complete the data table.

Hand out copies of Tides (S-7-9-3_Tides and KEY.docx). Have students complete the worksheet for independent practice.

Day 2: Moon Phases

Place a ball in the classroom where every student can see it. If possible, hang a ball from the ceiling or arrange students’ desks around the ball on top of a desk or table. Darken the classroom as much as possible. In the corner, turn on an overhead projector light or lamp with shade removed. Have each student sketch the ball, showing light and shadowed parts, from wherever they are sitting. Turn the lights on, and compare the sketches. Ask, “What caused the differences?” (The positions of students in relation to the light and the ball.)

Remind students that the Moon is Earth’s only natural satellite, and its diameter is only about 1/4 of Earth’s diameter. Ask, “How long does it take the Moon to orbit the Earth?” (Students may say 27.3 days or 4 weeks; the exact time is 27.3 days.)

Divide students in groups of three or four. Assign each group a moon phase: new, waxing crescent, first quarter, waxing gibbous, full, waning gibbous, third quarter, and waning crescent. Give each group a set of materials for the activity: chart paper, markers, ruler, small foam ball, large foam ball, toothpicks, flashlight, large flat sheet of foam or cardboard.

Have students use markers to draw a large diagram on a piece of chart paper that shows the positions of the Moon, Earth, and Sun during their assigned phase.

Have groups create a three-dimensional model of the phase by attaching the toothpicks and balls to the sheet of foam core. Then have them use a flashlight to represent the Sun. Darken the room when all the groups are ready to test their model. Have them make changes as needed to get the correct moon phase.

With the room darkened, have each group explain to the class why we see their Moon phase. Have them role-play the phase with the overhead/lamp as the Sun, one person as the Earth, and one person holding the large beach ball/playground ball as the Moon. Have the person who is the “Earth” guess the phase of the moon.

Show students the Moon Phases resource and describe the shape of the moon and whether it is waxing or waning in each of the phases (S-7-9-3_Moon Phases Chart.docx). Give students the Moon Phases Worksheet (S-7-9-3_Moon Phases Worksheet and KEY.docx). Have them complete Parts 1 and 2 of the worksheet. For reinforcement, it may be helpful to have them write definitions for the boldfaced terms from the reading selection.

Day 3: Lunar Eclipses

Ask students to recall what happens to the Moon on nights that we cannot see it. Remind them that the Moon does not actually disappear, but we cannot see it because the Sun is shining on the side of the Moon that we cannot see. Ask students, “What would happen if the Moon were to line up with the Earth and the Sun?”

Tell students that today’s lesson is about lunar eclipses and have them write the definition in their notes. Instruct students to draw three circles in their science notebooks, labeling the Sun as the first circle on the left. Tell students to label the Earth and the Moon as they think they would be arranged during a lunar eclipse. See diagrams below for the alignment of Sun, Earth, and Moon. Show students the Lunar Eclipse Diagram (see S-7-9-3_Lunar Eclipse Diagram in the Resources folder). Point out the umbra and penumbra and explain the role of each of them during a lunar eclipse.

• Penumbra: The part of a shadow within which the source of light is only partially blocked out. The penumbral shadow is a zone where the Earth blocks part but not all of the Sun’s rays from reaching the Moon.
• Umbra: The central, darkest portion of a shadow. The region which does not receive direct rays from any part of a light source. The umbral shadow is a region where the Earth blocks all direct sunlight from reaching the Moon.

Explain, “Lunar eclipses occur because the Moon is in the shadow of the Earth only when the Sun, Earth, and Moon are positioned on the same plane in a straight line.” Note: It is important to tell students that a lunar eclipse can only occur during a full moon.

Lunar Eclipse:

Source: http://en.wikipedia.org/wiki/Lunar_eclipse

Use the overhead projector or lamp with shade removed (“Sun”), large ball (“Earth”), and a much smaller foam ball (“Moon”) to model a lunar eclipse. Have student volunteers hold the balls and have the class direct them to the correct positions for a lunar eclipse. Then, turn out the lights and check the model. If needed, reposition the “Earth” and “Moon” until the model demonstrates a lunar eclipse.

Ask, “What happens when the Moon is directly between the Sun and the Earth and the Moon’s shadow falls on the Earth?” (There is an eclipse of the Sun, a solar eclipse.) Explain how a solar eclipse occurs. The diagram below may be helpful in your explanation.

Source: http://en.wikipedia.org/wiki/File:Geometry_of_a_Total_Solar_Eclipse.svg

Assess students’ understanding by having each student create a labeled diagram showing the location of the Sun, Moon, and Earth for a lunar eclipse.

If there is extra time at the end of this lesson, have students create flash cards to review the vocabulary terms from this lesson on tides, moon phases, and lunar eclipses.

Extension:

• Students who may be going beyond the standards can write a short essay in response to the following questions:

o   “What do you think it would be like if the Earth had two moons?”

o   “Would it affect the tides?”

o   “What about the calendar?”

• Students who may be going beyond the standards can research the difference between lunar and solar eclipses, and find out when the next lunar eclipse will occur. Data can be found on the NASA Lunar Eclipse Page, http://eclipse.gsfc.nasa.gov/lunar.html
• Students who might need an opportunity for additional learning can use a water balloon to demonstrate how gravity causes tides. Pull on the tied end of the balloon and have students observe the bulges on two sides and flattening on the other sides.
• Students who might need an opportunity for additional learning can write definitions, in their own words, for each boldfaced vocabulary term on the Moon Phases Worksheet (S-7-9-3_Moon Phases Worksheet and KEY.docx).
• Create a flip-book of the eight moon phases; each page should have a circle that is the same size. Students can shade in the appropriate amount of the Moon and label each phase, then flip through the pages to show the moon cycle.
• Have students create a picture dictionary for the vocabulary concepts from this lesson.