Phases of the Moon:
Planetarium show for Middle School Children
Post-Show Activity 1
Reaping Rocks

Students will make predictions about the origin of lunar rocks by first collecting, describing, and classifying neighborhood rocks.

Grade Level
9 - 12

Materials Background
Geologists are scientists who study the formation, structure, history, and processes (internal and on the surface) that change Earth and other planetary bodies.

Rocks and the minerals in them give geologists key information about the events in a planet's history. By collecting, describing and classifying rocks, we can learn how the rocks were formed and what processes have changed them.

Geologists classify rocks into three types: We find all three rock types on Earth's surface and the rocks are constantly changing (recycling), very slowly because of heat, pressure, and exposure to weather and erosion.

The Moon's surface is dominated by igneous rocks. The lunar highlands are formed of anorthosite, an igneous rock predominantly of calcium-rich plagioclase feldspar. The lunar maria are made of layers of basaltic lava, not unlike the basaltic flows of the Columbia River Plateau or of Iceland. The orange glass found on the Moon's surface is another product of volcanic activity. Moon rocks are not exposed to weather nor are they eroded by wind, water, or ice. The Apollo astronaut's footprints are as fresh as the day they were made.

  1. Review and prepare materials listed on the student sheet. Spend time familiarizing the students with rock and mineral identification.
  2. Students may need more than one copy of "My Own Rock Chart" because it has spaces for only three samples. You may want to collect empty egg cartons, small boxes, or trays that the students could decorate themselves to display their rocks. Use of magnifying lenses or a stereo microscope would greatly enhance observations.
  3. "Moon ABCs Fact Sheet" may come in handy during the wrap-up when students try to make predictions about the Moon rocks.
  4. Talk about the qualities of rocks that we can describe: shape, size, color, texture, and the place where it was found. Then discuss the three rock classifications emphasizing that geologists classify rocks and interpret the origins of rocks based on their observations.
  5. Encourage students to collect a variety of rocks with different colors and textures from your own locality, if possible. Remind them to choose naturally occurring materials not cement or brick fragments! If it is not possible to collect rocks from the neighborhood, then try to obtain a commercially available set of common rocks. More than one student may choose the same rock. Students could also cut out pictures of rocks from magazines or study pictures of rocks in text books.
  6. After each rock has been labeled with owner's name and location where it was found, have the students look carefully at the rock. To help them train their eyes, ask questions like: What colors do you see? Do you see grains? Are the grains large or small? Does the rock look glassy? Or does the rock show a banding pattern? Does the rock look frothy with a lot of holes? Do you see pebbles cemented together? Does the rock contain fossils?
  7. Ask students to describe their rocks with as many adjectives or descriptive phrases as possible. Have the students classify the rocks as igneous, sedimentary, or metamorphic, and then try to interpret the rock origins. "My Own Rock Chart" is designed to help organize their observations and interpretations.

    Conclude the activity by challenging the students to predict what the lunar rocks look like and the possible origins based on what they have just learned about Earth rocks and based on the material in the "Moon ABCs Fact Sheet." Student Sheet Name ___________________ Date _________ Key Words: geologist, mineral, rock, igneous, sedimentary, metamorphic 1. Display your rocks on a tray or egg carton, and label each one with the location of where you found it. 2. Look carefully at each rock with and without a magnifying lens or stereo microscope. What details can you see under magnification? 3. Describe what you see by filling out "My Own Rock Chart." Use as many adjectives or descriptive phrases as you can. 4. Classify your rocks as igneous, sedimentary or metamorphic. Try to interpret how your rocks were formed; that is, try to determine the origins. Add this information to your chart. 5. Now, based on your chart and the "Moon ABCs Fact Sheet," predict what the Moon rocks will look like. 6. How do you think the different Moon rocks might have formed? Fact Sheet Property Earth Moon Brain Busters Equatorial diameter 12,756 km 3,476 km How long would it take to drive around the Moon's equator at 80 km per hour? Surface area 510 x 106 km2 37.8 x 106 km2 The Moon's surface area is similar to that of one of Earth's continents. Which one? Mass 5.98 x 1024 kg 7.35 x 1022 kg What percentage of Earth's mass is the Moon's mass? Volume ?? ?? Can you calculate the volumes of Earth and the Moon? Density 5.52 g/cm3 3.34 g/cm3 Check this by calculating the density from the mass and volume. Surface gravity 9.8 m/sec/sec 1.63 m/sec/sec What fraction of Earth's gravity is the Moon's gravity? Crust Silicate rocks. Silicate rocks. What portion of each body is crust? Continents Highlands dominated dominated by granites. by feldspar-rich Ocean crust rocks and dominated maria by by basalt. basalt Mantle Silicate rocks Similar to Collect some silicate rocks and dominated by Earth. determine the density. minerals Is the density greater or lesser containing iron than the Earth/Moon's density? Why? and magnesium. Core Iron, nickel Same, but What portion of each body is core? metal core is much smaller. Sediment or Silicon and Silicon and Do you think life ever existed on the Regolith oxygen bound oxygen bound Moon? Why or why not? in minerals in minerals, that contain glass produced water, plus by meteorite organic impacts, materials small amounts of gases (e.g., hydrogen) implanted by solar wind. No water or organic materials. Property Earth Moon Brain Busters Atmosphere 78 % nitrogen Some carbon Could you breathe the lunar (main constituents) 21 % oxygen gases but very atmosphere? little of them. Pressure is about one- trillionth of Earth's atmospheric pressure. Length of day 23.93 hours 27.3 Earth How long does daylight last on the (sidereal rotation days Moon? period) Temperature Air temperature Surface Why are the temperatures of Earth ranges from temperature and the Moon so different? -88C(winter in ranges from polar regions) -193C (night to 58C (summer in polar in tropical regions) to regions). 111C (day in equatorial regions). Surface features 25% land 84% heavily- Compare maps of Earth and the Moon. (seven cratered Is there any evidence that plate continents) highlands. tectonics operated on the Moon? with varied 16% basalt- terrain of covered mountains, maria. plains, river Numerous valleys. impact craters Ocean floor (some with characterized bright rays, by mountains, crater chains, plains, and and rilles). trenches. My Own Rock Chart OBSERVATIONS sample_____________ sample_____________ sample_____________ Sketch of Sample Shape Size Colors Texture Apollo Mission/ Collection Site INTERPRETATIONS sample___________ sample___________ sample___________ Classification Origin Hawai'i Space Grant College, Hawai'i Institute of Geophysics and Planetology, University of Hawai'i, 1996