Lesson Asteroids

Quick Look

Grade Level: 8 (7-9)

Time Required: 15 minutes

Lesson Dependency: None

Quick Look

Blast off into our curated resources featured here, by grade band, to engage your K-12 students in making sense of phenomena and the wonders of engineering in space! Space
Grade Level:
8 (7 – 9)
Time Required:
15 minutes
Discuss this lesson

TE Newsletter

A fiery asteroid approaching planet Earth.
The potential danger of an asteroid colliding with Earth
copyright
Copyright © Pixabay, Creative Commons CC0. https://pixabay.com/en/armageddon-apocalypse-earth-2104385/

Summary

Students learn some basic facts about asteroids in our solar system, mainly about the size of asteroids and how that relates to the potential danger of an asteroid colliding with the Earth. Students are briefly introduced to the destruction that would ensue should a large asteroid hit, as it did 65 million years ago. Students are then encouraged to use the associated activity to research the impacts and potential actions to prevent such events on Earth.

Engineering Connection

Engineers at NASA create technological tools to learn about asteroids. People working on the Near-Earth-Object (NEO) project study how asteroids move so we can predict whether they will hit the Earth. Software engineers design the computer programs to make these predictions. Mechanical and aerospace engineers on this project create space probes to learn more about asteroids by taking photographs of them and, in the case of the NEAR Shoemaker probe, even landing on a large asteroid.

Learning Objectives

After this lesson, students should be able to:

  • Explain what asteroids are and compare them to other objects in the solar system.
  • State how big an asteroid must be to cause mass destruction on Earth.
  • Explain why engineers design technological tools to predict the movement of asteroids.

Worksheets and Attachments

Visit [www.teachengineering.org/curriculum/print/cub_space8_lesson03] to print or download.

Introduction/Motivation

In the 1998 hit movie "Armageddon," an asteroid the size of Texas is on a collision path with Earth and is predicted to destroy all life as we know it. How real is this scenario? Well, we will answer that question today, but first, let's look at some background information about asteroids.

Asteroids are objects that revolve around the Sun, mostly in the region between Mars and Jupiter known as the asteroid belt (see Transparency #1; also shown in Figure 2).

A diagram shows the location of asteroids in our solar system. Jupiter's orbit is about 5 astronomical units in radius, and the asteroid belt has a radius of about 2.7 astronomical units.
Figure 2. The Main Asteroid Belt, shown inside the outer ring, is the area of our solar system containing most of the known asteroids.
copyright
Copyright © Solar System Exploration, National Aeronautics and Space Administration http://solarsystem.nasa.gov/multimedia/gallery/Asteroid_Belt.jpg

How big are asteroids? (Listen to student ideas.) Their sizes can be quite variable! The smallest known asteroid is 6 m (or, almost 20 ft.) across—it could easily fit in our classroom. The Gaspra Asteroid (show Transparency #2; same as Figure 1) is 17 km (or, more than 10.5 miles!) across. How big is that? Could we fit a city block, small town, a big city, our state, or the whole country across something that big? (Have students raise their hands for a quick vote. Answer: A small town.) More than 200 asteroids in the belt between Mars and Jupiter are more than 100 km across. If we were to drive 100 km from our school, where would we end up? (100 km = ~62 miles. Be prepared to have location examples for students, depending on where you live. This helps students understand the scale.)

What would happen if one of these asteroids hit the Earth? (Listen to student ideas). Have students simulate their predictions of such events with the Earth Impact activity. Well, it depends on its size. Those that are less than 40 m across (about as big as a small office building) would be destroyed by the Earth's atmosphere and not do any damage. If one as large as 2 km in diameter hit the planet, it might cause disaster on a global scale. Not only would its crashing pieces cause instant destruction and death, but the dust created by the crash would set off a change in weather that would kill a huge fraction of all the living things on Earth. It is believed that this is what happened 65 million years ago when a meteor 6 miles across hit the Chicxulub Basin in Mexico, resulting in mass extinction, including dinosaurs.

Fortunately, scientists predict that your chances of being killed by an asteroid impact are very low (1 in 40,000). Currently, no known asteroids are on a collision path with Earth. However, every 1 or 2 million years, the Earth could be hit by an asteroid large enough to cause global destruction and kill most people on Earth. To prevent this, engineers are seeking ways to destroy or divert asteroids before they hit us (just like in the movie "Armageddon")!

Lesson Background and Concepts for Teachers

Asteroid Fast Facts

Asteroids are objects ranging in size from 6 m to 933 km across that revolve around the Sun. The asteroid belt contains millions of asteroids that are less than 1 km in diameter. More than 750,000 are bigger, and of those, at least 200 are more than 100 km across. Asteroids in the outer part of the belt are composed mainly of carbon, while those located in the inner part of the belt are made primarily of minerals, since they are derived from melted objects.

Although scientists are not certain how they came about, it is believed that they are the result of collisions of much larger objects occurring around the time that our solar system was formed. Some asteroids, on the other hand, are derived from the tails of comets.

History of Asteroid Collisions with Earth

Researchers at NASA have been actively tracking near Earth asteroids (NEAs) to determine whether or not they will hit. Jupiter's gravitational field pulls on asteroids just enough to slowly change their trajectories. With the advancement of computer models and tracking devices (created completely, or in part, by engineers!), scientists can predict the future trajectories of asteroids. So far, they have found that no asteroids are on a collision course with Earth.

Historically, the Earth was not always so lucky. A very long time ago—65 million years to be exact—an asteroid hit an area in present-day Mexico, leaving behind a 300 km-wide crater. It is hypothesized that this asteroid caused the mass extinction of life at that time, including dinosaurs. More recently, in 1908, a smaller object (either an asteroid or comet tail) hit Siberia, destroying forested land in an area about 50 m in diameter.

Fortunately, most asteroids that come within proximity of the Earth do no damage. As small (<40 m in diameter) asteroids hit the atmosphere, they burn up, giving off the characteristic trademark of a meteor. (Meteors are small objects that have entered the Earth's atmosphere, either from comets, asteroids, or other objects in our solar system.) This also explains why the Moon looks more "beat-up" than the Earth. The Moon does not have an atmosphere, and therefore, upon collision, even small objects cause craters on the Moon.

Lesson Closure

Scientists and engineers are very interested in near-Earth asteroids because we know that at some point in the future (even if it is a million years away), the Earth could be impacted by an asteroid collision. It is important that researchers know what to look for in order to predict and prevent asteroid impacts that could cause devastation on Earth. While many people study the solar system for its beauty and tranquility, others study it to learn about the unknown to understand and help predict our celestial movement—both good and potentially dangerous movement.

Vocabulary/Definitions

asteroid: A celestial body that orbits the Sun; ranges in size from 6 m to 933 km.

comet: A celestial body with a solid core and followed by a tail of debris; normally has a highly elliptical orbit.

meteor: A flash of light caused by particles from outer space entering the Earth's atmosphere; typically originates from asteroid collisions.

Assessment

Pre-Lesson Assessment

Voting: Ask true/false questions and have students vote by holding thumbs up for true and thumbs down for false. Tally the votes and write the totals on the board. Give students the right answers:

  • T or F: The solar system consists only of the Sun, the planets, and their moons. (Answer: False; millions of asteroids exist in our solar system.)
  • T or F: If an asteroid hit the Earth, it would knock everyone off the planet. (Answer: False; asteroids are much smaller than the Earth. Most asteroids burn up when they hit the atmosphere and do no damage at all. Some large asteroids have done tremendous damage, but they are still not massive enough to knock things off the planet, or to knock the Earth out of orbit.)

Post-Introduction Assessment

Idea Web: Ask students to brainstorm a list of possible consequences of an asteroid hitting the Earth. How does one of these consequences lead to another? (For instance, as the asteroid hits, it creates a crater and sends dust and debris flying, the dust obscures the Sun, less Sun causes lower temperatures, etc.). Help students see how the single event of an asteroid impact could set off a domino-like chain reaction of changes that impact life on the planet.

Lesson Summary Assessment

Question/Answer: Have students answer the following question in a short paragraph in their journals or on a sheets of paper:

  • What role do engineers have in preventing the catastrophe of an asteroid hitting the Earth?

Lesson Extension Activities

Build a scale model of objects in the solar system, with help from the following NASA website. Include an indication of where the asteroid belt would be. http://www.nasa.gov/offices/education/programs/national/summer/education_resources/earthspacescience_grades7-9/ESS_ss-scale-models.html

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References

Grayzeck, Ed, "Asteroids." (photo gallery). National Space Science Data Center, National Aeronautics and Space Administration, http://nssdc.gsfc.nasa.gov/photo_gallery/photogallery-asteroids.html

Lindstrom, Marilyn. "Asteroid Belt." (graphic). Multimedia, Solar System Exploration, National Aeronautics and Space Administration, http://solarsystem.nasa.gov/multimedia/gallery/Asteroid_Belt.jpg

Copyright

© 2008 by Regents of the University of Colorado

Contributors

Brian Kay; Karen King; Janet Yowell

Supporting Program

Integrated Teaching and Learning Program , College of Engineering, University of Colorado Boulder

Acknowledgements

The contents of these digital library curricula were developed by the Integrated Teaching and Learning Program under National Science Foundation GK-12 grant no. 0338326. However, these contents do not necessarily represent the policies of the National Science Foundation, and you should not assume endorsement by the federal government.

Last modified: May 18, 2021

Hands-on Activity Earth Impact

Quick Look

Grade Level: 8 (7-9)

Time Required: 1 hour

Expendable Cost/Group: US $3.00

Group Size: 3

Activity Dependency: None

Quick Look

Partial design Partial design process
Grade Level:
8 (7 – 9)
Time Required:
1 hour
Group Size:
3
Discuss this activity

TE Newsletter

Aerial photo shows expanse of dry earth with some roads, with a very large bowl-shaped depression into the ground surface.
1-km wide Barringer Crater, located 38 miles east of Flagstaff, AZ.
copyright
Copyright © Near-Earth Object Program, National Aeronautics and Space Administration http://neo.jpl.nasa.gov/images/meteorcrater.jpg

Summary

This activity poses the question: What would happen if a meteor or comet impacted Earth? Students simulate an impact in a container of sand using various-sized rocks, all while measuring, recording and graphing results and conclusions. Then students brainstorm ways to prevent an object from hitting the Earth.

Engineering Connection

Engineers play a vital role in both the observation of what are called near-Earth objects (meteors, comets, asteroids, etc.) as well as any future destruction of them. All types of engineers, from mechanical engineers and aerospace engineers to chemical engineers, participate in designing, testing and building satellites that orbit any object in space, be it Earth or another planet. These satellites, in addition to telescopes, help scientists observe and document objects that have the potential to impact Earth. In the future, any plan to prevent an object from hitting the Earth will no doubt utilize engineers from a variety of disciplines.

Learning Objectives

After this activity, students should be able to:

  • Explain the relationship between various-sized objects, impact speed and crater size (and have data to back it up).
  • Describe at least one way to prevent a near-Earth object from impacting Earth.

Materials List

Each group needs:

  • 1 plastic container, ~2 ft2 x 2-5 inches high
  • enough sand to fill the entire container, to at least 1.5 inches
  • 4 different-sized, spherical-shaped rocks of equal density
  • 12-inch ruler
  • meter or yard stick
  • 1 sheet of blank paper (or, use the reverse side of the worksheet if it is copied single sided)
  • How Big is That Crater? Worksheet

Worksheets and Attachments

Visit [www.teachengineering.org/curriculum/print/cub_space8_lesson03] to print or download.

Pre-Req Knowledge

A basic understanding of measurement and graphing.

Introduction/Motivation

What would happen if a giant meteor hit the Earth? Would civilization as we know it continue to exist? Would the entire planet disintegrate as a result of the blast? (Ask students to share some of their thoughts that they recorded in their journals at the start of class; see the Assessment section.) According to scientists, an event like this is possible in the future. To be prepared for such a potential catastrophe, scientists are working with engineers to come up with solutions to prevent impact from happening.

The Earth already passes through the orbit of many comets and asteroids. Fortunately, no object of appreciable size has impacted the Earth in modern times. Our planet has been hit by these objects before however; evidence can be found in the craters that exist all over the world. It is thought that dinosaurs became extinct after a large meteor stuck Mexico millions of years ago. If another impact as large as that one hit the Earth today, it would be just as devastating as it was then.

How could you prevent an asteroid or comet from hitting Earth? Today you will come up with a design for such an Earth protector. To design a solution, engineers first learn more about the problem. For example, in 2005, NASA's deep impact probe intentionally slammed into a comet in order to help scientists understand the composition of comets first hand. In this activity, we will look at the devastating effects of falling objects (similar to what we would see if a meteor hit the Earth). This will help us make an informed design for a way to prevent a future catastrophe.

Procedure

Before the Activity

With the Students

  1. Divide the class into groups of three students each.
  2. Pass out the worksheets to each group.
  3. Have students decide who will start in the following roles: data recorder, crater measurer, and meteoroid dropper. Direct students to take turns at each role throughout the activity.
  4. Have students carefully collect the container of sand for their group.

Experiment 1 (20 min)

In this experiment, students first observe the crater size made by meteoroids (rocks) of different sizes.

  1. Have teams make predictions in the first section of their worksheets, describing what they think will happen as they drop their three meteoroids (rocks) into the sand containers. Ask questions such as: Which rock will make the largest crater and why? Remind students that to drop the rocks from the exact same height (and have them record the reason for this on their worksheets).
  2. Once predictions are made, have students begin the experiment. Have them either start with the smallest rock and move up in size, or the largest rock and move down in size.
  3. Have students drop each rock three times and record the crater diameter, crater depth (after removing the rock from the container), as well as any other observations. Have them measure in inches or centimeters, depending on the class convention. Make sure they record on their worksheets the height they are dropping the rocks from.
  4. Have students complete the questions under Experiment 1 on the worksheets.

Experiment 2 (20 min)

In this experiment, students test the size of their craters in relationship to the speed of the impact of the rocks.

  1. Instruct students to choose only one of their rocks. Ask them why they should use the same rock as they collect data in the next experiment. (Answer: In controlled experiments, you should only change one variable at a time. Since the height — and therefore the impact velocity — will be increased in this experiment, the size of the rock should remain constant.)
  2. As in the first experiment, have students make predictions of what will happen with regards to the size of the craters if they increase their drop height. (Question #1 in the Experiment 2 section of the worksheet.)
  3. Encourage students to design this experiment themselves, using the guiding question, "As I increase the height that I drop the rock from, how will the crater size change?" Explain that by increasing the height, we are effectively increasing the impact velocity. Discuss why this is a better scientific strategy than just dropping the rock at varying speeds. (Answer: It is easier to have a systematic process that can reproducible from trial to trial; you are controlling your variables with a systematic approach).
  4. Give groups a few minutes to jot down their plan for the experiment and create a table for data collection (Question #2, Experiment 2 of the worksheet). Sign off on their work before they get started. The data table should be similar to the first experiment, with rock height replacing rock size. Have students choose three rock drop heights that will be easy to repeat, such as, knee height, waist height, shoulder height, etc.
  5. As before, if time permits, have students collect extra data and make a plot of crater diameter versus impact speed (height). Students need an extra sheet of paper for this step.
  6. Ask students to use their findings to make a prediction about what effect the velocity of a meteor would have on a crater it creates on the Earth.

Designing an Earth Protector (5 min)

Students generate ideas for how to prevent the catastrophe that would ensue if a large meteor hit the Earth.

  1. Have students reflect on their experimental results and consider what their new understanding of impact tells them about an actual meteor hitting the Earth. Have them jot down ways in which this knowledge could be applied to the design of an Earth Protector, a device that would prevent a meteor from damaging the Earth.
  2. Ask students to brainstorm ideas for designing an Earth Protector. In the designated space on their worksheets, instruct students to draw a diagram of their Earth Protectors, labeling the various components.
  3. Give teams a few minutes to discuss the advantages and disadvantages of various methods. Then have them pick a design and a spokesperson to communicate that design. Suggest they draw diagrams to help explain their ideas.

Vocabulary/Definitions

asteroid: A celestial body that orbits the Sun; ranges in size from 6 m to 933 km.

comet: A celestial body with a solid core and followed by a tail of debris; usually has a highly elliptical orbit.

meteor: A flash of light caused by particles from outer space entering the Earth's atmosphere; typically originates from asteroid collisions.

Assessment

Pre-Activity Assessment

Prediction: Have students predict the outcome of the activity before the activity is performed. Have students record their predictions in the first section of the How Big is That Crater? Worksheet.

  • Will a larger rock produce a large crater? If so, how much larger?
  • Will a rock falling from a higher distance produce a larger crater? Why?

Class Discussion: Ask students to consider what the world would be like if a meteor were to hit Earth. What would be the impact on the environment? How would it affect our society?

Activity Embedded Assessment

Worksheet: Have students follow and complete the How Big is That Crater? Worksheet. Monitor the information they are recording to gauge their understanding of the subject matter and of the importance of a well-thought-out and -performed experiment.

Group Question: During the activity, ask the teams:

  • How could this experiment help you design a way to prevent a meteor from destroying the Earth? What information does this test give you that would be helpful in the design stage?

Post-Activity Assessment

Prediction Analysis: Have students compare their initial predictions with their test results, as recorded on their worksheets. Ask the students to explain why faster and larger objects leave larger craters. Challenge them to consider how their findings impact their design process for an Earth Protector.

Class Presentation: Have student teams present their Earth protectors to the rest of the class.

Voting: When all of the presentations are completed, have the class vote for the best design.

Safety Issues

  • Watch that students do not throw the rocks at each other or around the classroom.

Troubleshooting Tips

Remind students to drop — not throw — the rocks, as this might skew their data.

For accuracy in measurements, remind students to be careful when removing their rocks from the sand so as to not alter the crater depth.

Activity Extensions

The design component of this activity could be greatly expanded, depending on how much time can be allotted to the project. Students could write a design proposal, sketch their idea, make a poster presentation, build a scale model, etc. To promote interest, watch the movie "Armageddon," which shows a fictionalized account of scientists and engineers trying to prevent an asteroid from colliding with Earth. To help students gather information about what real engineers are doing to ward off meteor collisions, point them to this article on "gravity tractors" (http://www.cnn.com/2006/TECH/space/02/09/asteroid.tractor/index.html).

In the NOVA special "Einstein's Big Idea" (http://www.pbs.org/wgbh/nova/einstein/), Émilie du Châtelet, a French aristocratic woman of the early 18th century performs an experiment similar to Experiment 2 in this activity. She argued for the idea that energy is proportional to velocity squared. Have students use the evidence from their experiment to support or refute her claims. (The experiment should support it. Dropping a rock from twice the initial height should result in a crater depth that is four times as great. This can be proven from work-energy equations PE = mgh, KE=1/2mv2 and Work = Fd).

Activity Scaling

  • For lower grades, eliminate the graphing portion of the activity. If students struggle with taking measurements, have them make qualitative (rather than quantitative) observations of the crater size.
  • For grades 9-10, have students calculate the impact velocity for the second experiment. Either give them the relationship ( v=(2gh)1/2 ), or have them derive it from conservation of energy (PE = mgh; KE=1/2mv2 ). If time permits, have students investigate the crater made by differently-shaped rocks. They might also observe the craters created when rocks impact the sand from an angle by underhand tossing of them into the container. It is near impossible to make exactly-the-same angled throws into the sand in order to collect and analyze data, but at least students can observe some of the effects of this type of impact and compare it to the vertical drops done earlier.

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References

Kohn, David. Popular Science on cnn.com, "Spaceship could help Earth avoid asteroid collision," February 9, 2006, accessed November 27, 2008. http://www.cnn.com/2006/TECH/space/02/09/asteroid.tractor/index.html

Near-Earth Object Program, National Aeronautics and Space Administration, accessed November 27, 2008. http://neo.jpl.nasa.gov/images/meteorcrater.jpg

WGBH Educational Foundation, Nova Science Programming On Air and Online, "Einstein's Big Idea," accessed November 27, 2008. http://www.pbs.org/wgbh/nova/einstein/

Copyright

© 2008 by Regents of the University of Colorado.

Contributors

Brian Kay; Karen King; Janet Yowell

Supporting Program

Integrated Teaching and Learning Program, College of Engineering, University of Colorado Boulder

Acknowledgements

The contents of this digital library curriculum were developed under a grant from the Fund for the Improvement of Postsecondary Education (FIPSE), U.S. Department of Education, and National Science Foundation GK-12 grant no 0338326. However, these contents do not necessarily represent the policies of the Department of Education or National Science Foundation, and you should not assume endorsement by the federal government.

Last modified: May 18, 2021