On A Collision Course: The Moon
Summary
Impact craters are found on nearly all solid surface planets and satellites. Although this exercise simulates the impact process, it must be noted that the physical variables do not scale in a simple way to compare with full-size crater formation. In other words, this exercise is a good approximation but not the real thing. Impact craters form when objects from space, such as asteroids, impact the surface of a planet or moon. The size of the crater formed depends on the amount of kinetic energy possessed by the impacting object. During impact the kinetic energy of the object is transferred to the target surface.
The students will experiment with creating craters! Each group will first be given photos of actual craters on the moon. This part is strictly for observation and discussion. Students will then work as a group to test different sizes, different masses or it could be an object with the same size and mass.Students will conduct the experiment using the Scientific Method (observation of actual moon crater images, predicting what caused them, write a procedure, conduct the experiment, record results on a data table, and come to a conclusion). Each group will present their results.
Learning Goals
Students will work in groups of 4 to demonstrate how impact craters on the moon were formed.Students will determine how the height above the surface, the mass of the object, and the radius of the object affects the size and shape of the impact crater.Average speed will be determined.Results will be recorded on a data table.Each group will be testing different objects.
Context for Use
This lesson is part of a Earth-Moon System unit taught at the 6th grade level. The lesson is meant for a heterogeneous class, where students of all levels are grouped. Throughout the unit students will be finding information that will be used to produce a "travel" brochure to the moon.Students will learn about the surface features of the moon including: maria, craters, lunar highlands,rays and rills.Throughout the unit students will be making nightly observations and recording the nightly phase of the moon.
Prior to this lesson students should understand the concept of mass, radius and kinetic energy. They should also know how to calculate speed.Students need to know how to measure mass using a triple beam balance, and have experience with creating and/or reading a data table.This lesson on craters should take one to two periods.
The following vocabulary terms will be introduced prior to this lesson:
*Ejecta
Material surrounding the crater that was excavated during the impact event. Ejecta becomes thinner away from the crater.
* Rille
Long valley of the moon
*Rays
Bright streaks starting from a crater and extending away for great distances.
*Highlands
Mountains on the moon
* Maria
Dark, broad, smooth lowland area on the moon
* Craters
Bowl-shaped depressions on the surface of the Moon caused by impact from meteorites.
* Meteorite
Piece of rock that hit the Moon, Earth, or another planet from space.
* Radius
Half the diameter of any sphere or circle
* Average Speed
Distance divided by time
* Mass
The amount of matter in an object
Description and Teaching Materials
In-Class Activities
1. After students have been divided into groups of 4, they will observe photos of actual craters on the moon. Each group will discuss and decide what caused the craters to be different in size and shape and random in location. Their hypotheses will be written somewhere in the classroom for all to read.
2. Each group will given the following: an object for creating craters, a triple beam balance, a ruler using cm, newspaper, an empty pizza box, plain sand, colored sand, data table worksheet, and a stop watch. The teacher will determine the groups of objects to be tested.(i.e. large steel ball bearing, a super ball, a round piece of styrofoam...) At the sixth grade level a teacher prepared data table works best, especially at the beginning of the school year. Results will be recorded on the Impact Crater Data table.
3. Each group will work together and determine the mass and radius.Record results on Impact Crater Data table.Each student will be responsible for filling a data table in. Impact Craters Data (Microsoft Word 89kB Jul28 11)
4. Students will follow the Impact Crater Lab form using the scientific method. Impact Crater Lab Form (Microsoft Word 73kB Jul28 11)
5. The empty pizza box (with newspaper under it) will be filled with plain sand and lightly covered with the colored sand. Before colored sand is applied, shake box gently to even out the surface. After each drop, the sand must be evened out again, and the colored sand reapplied.
6. Students will drop the object from a height of 30 cm. One student in the group can use the stop watch to help figure out average speed. A few practice drops is recommended.Students will measure and record the diameter of the crater, the depth of the crater and the length of the rays (if created). Record results on the Impact Crater Data table. (If finding the depth becomes a problem because it is not deep enough, that data will be eliminated.)
7. Steps 5 and 6 are repeated for heights of 60cm and 90 cm.
8. Each student will take turns testing the object. All group members are to work cooperatively and help each other in following the proper procedure.Each student will be responsible for filling in a lab report. The results and conclusion sections can be decided as a group. One person should be assigned to sketch the craters that were created, so as to compare with the other groups.**If time permits each group will be given another object to test.
9. After the data has been collected, a group discussion will follow. What affected the crater shape, crater depth and length of the rays? How is this lab so different from what actually happens on the moon? Does the mass and radius play a role in determining crater shape and depth?
At Home Assignments
For homework the students will be asked to come up with reasons why the moon's far side is relatively smooth with maria, while the far side is covered with craters."Crumble and Toss" activity:during the next class, students will write down their best reason on a piece of paper anonymously. The paper will be crumbled and tossed in a box.Each student will take a piece of paper (keeping quiet if they get their own) and will work in a group of 4 to decide who had the best answer.All the "best" answers will be read out loud. A class discussion might decide who had the best explantion- but it will still be anonymous.:)
Materials
For each student group: Sand, tray, colored sand, drop cloth or pizza box, screen or flour sifter, safety Goggles (one for each student), triple beam balance, ruler,and calculator. Projectiles: different sizes of steel ball bearings: identical steel ball bearings , identical sized objects with different densities (large ball bearing, marble, wood or foam ball, rubber superball).Standards
Massachusetts Science and Technology/Engineering Curriculum Framework
EARTH SCIENCE
8. Recognize that gravity is a force that pulls all things on and near the earth toward the center of the earth. Gravity plays a major role in the formation of the planets, stars, and solar system and in determining their motions.
10.Compare and contrast properties and conditions of objects in the solar system (i.e., sun, planets, and moons) to those on Earth (i.e., gravitational force, distance from the sun, speed, movement, temperature, and atmospheric conditions).
PHYSICAL SCIENCE
1.Differentiate between weight and mass, recognizing that weight is the amount of gravitational pull on an object.
11.Explain and give examples of how the motion of an object can be described by its position, direction of motion, and speed.
13.Differentiate between potential and kinetic energy. Identify situations where kinetic energy is transformed into potential energy and vice versa.
Assessment
Each student is expected to fill in a data chart, as well as a lab report. The lab report can be assessed using the Science Lab Rubric - see Resources (Biology Corner).Groups will present their findings to the class.
References and Resources
http://www.windows2universe.org/earth/moon1.html - Lunar Geology
http://www.nasa.gov/pdf/58263main_Planetary.Geology.pdf Planetary Geology
http://www.enchantedlearning.com/subjects/astronomy/moon/Craters.shtml Simple explanation of impact craters
http://hyperphysics.phy-astr.gsu.edu/hbase/solar/mooncrater.html Terrific Phots of impact craters on hte moon
http://www.lpi.usra.edu/expmoon/science/craterstructure.html Cross section views of impact craters
http://www.biologycorner.com/worksheets/labreport_rubric.html - Science Lab Rubric**