Moon - STEM @ Worcester County Library
Moon - STEM @ Worcester County Library
Through discussion and two experiments, participants will explore how the maria that covers about 16% of the moon's surface was formed and the science behind moon craters. We will also discuss the different types of rock that have been discovered on the moon and how they differ from those found on Earth.
SUPPLIES
Trays, play-dough, food coloring, water, squeeze bottles, cookie sheets, plastic sheets, graham crackers, marbles, lunar disks
INSTRUCTIONS
Step 1 - Introduction
First, take a tour of the moon with a video from NASA. Then go into much greater detail with a Moon Crash Course from PBS. YouTube video:
https://youtu.be/2iSZMv64wuU YouTube video:
Step 2 - Lava Layering Activity
(Note: The lab sheet is included in the student handout)
Dark, flat maria (layers of basaltic lava flows) cover about 16 percent of the Moon’s total surface. They are easily seen on a full Moon with the naked eye on clear nights from most backyards. The maria, quite similar to Earth’s basalts, generally flowed long distances utlimately flooding low-lying areas such as impact basins. Yet, the eruption sources for most of the lunar lava flows are diffcult to identify. The diffculty in fnding source areas results from burial by younger flows and/or erosion from meteoritic bombardment.
Generally, the overall slope of the surface, local topographic relief (small cliffs and depressions), and eruption direction influence the path of lava flows. Detailed maps of the geology of the Moon from photographs reveal areas of complicated lava layering.
The study of rock layering is called stratigraphy.
On the Moon, older flows become covered by younger flows and/or become more pocked with impact craters.
On Earth, older lava flows tend to be more weathered (broken) and may have more vegetation than younger flows. Field geologists use differences in roughness, color, and chemistry to further differentiate between lava flows. They also follow the flow margins, channels, and levees to try to trace lava flows back to the source area.
The focus of this activity is on the patterns of lava flows produced by multiple eruptions. We use a short cup to hold the baking soda because we are looking at the flows and not at constructing a volcano model. Volcanoes, like those so familiar to us on Earth and Mars, are not present on the Moon. Three well-known areas on the Moon interpreted as important volcanic complexes are: Aristarchus plateau, and the Marius Hills and Rumker Hills (both located in Oceanus Procellarum). These areas are characterized by sinuous rilles (interpreted as former lava channels and/or collapsed lava tubes) and numerous domes.
Attachments:
Step 3 - Impact Craters
(Note: The lab sheet is included in the student handout)
The circular features so obvious on the Moon’s surface are impact craters formed when impactors smashed into the surface. The explosion and excavation of materials at the impacted site created piles of rock (called ejecta) around the circular hole as well as bright streaks of target material (called rays) thrown for great distances.
Two basic methods forming craters in nature are:
- impact of a projectile on the surface and
- collapse of the top of a volcano creating a crater termed caldera.
By studying all types of craters on Earth and by creating impact craters in experimental laboratories geologists concluded that the Moon's craters are impact in origin.
The factors affecting the appearance of impact craters and ejecta are the size and velocity of the impactor, and the geology of the target surface. By recording the number, size, and extent of erosion of craters, lunar geologists can determine the ages of different surface units on the Moon and can piece together the geologic history. This technique works because older surfaces are exposed to impacting meteorites for a longer period of time than are younger surfaces.
Impact craters are not unique to the Moon. They are found on all the terrestrial planets and on many moons of the outer planets. On Earth, impact craters are not as easily recognized because of weathering and erosion. Famous impact craters on Earth are Meteor Crater in Arizona, U.S.A.; Manicouagan in Quebec, Canada; Sudbury in Ontario, Canada; Ries Crater in Germany, and Chicxulub on the Yucatan coast in Mexico. Chicxulub is considered by most scientists as the source crater of the catastrophe that led to the extinction of the dinosaurs at the end of the Cretaceous period. An interesting fact about the Chicxulub crater is that you cannot see it. Its circular structure is nearly a kilometer below the surface and was originally identifed from magnetic and gravity data.
Attachments:
Step 4 - Lunar Rocks
(Note: The lab sheet is included in the student handout)
The six Apollo missions that landed astronauts on the Moon returned a collection of rocks and sediment samples weighing 382 kilograms and consisting of more than 2,000 separate samples. Each lunar disk contains six small samples of lunar material.
Descriptions of the samples accompany every disk; included are annotated color photographs, discussion of origins, and Apollo missions and collection sites.
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