Asteroid-Smashertoid!
Targeted grades: 3-5Developed by Bryan Street
OVERVIEW
We frequently make decisions about new situations based on evidence and personal experience. When scientists and mathematicians lack hands-on knowledge on which to base decisions, they create models or situations and observe the outcomes.
This lesson introduces students to using models/simulation to explore probability. Using an inflatable globe, students simulate where an asteroid or comet could hit the surface of the Earth. Will the asteroid hit land or water? Students are encouraged to make predictions based on prior knowledge of the Earth's geographic features and use the data that they have collected to evaluate and make predictions on where an asteroid might hit the Earth.
A computer simulation from a television special is initially used to engage the students. Later they critically analyze the content of the clip and consider who the program's audience might be.
Prior Knowledge: This lesson is designed to be in the middle or near the end of a unit on probability.
VIDEO
National Geographic: "Asteroid: Deadly Impact" (broadcast in Spring 1997)
Alternatives:
Discovery Channel "Three Minutes To Impact" (1997)
TBS--"Fire From the Sky" (1997)
NOVA--"The Doomsday Asteroid" (1997)
Movie--"Asteroid" (1997)
Additional Resource: PBS MATHLINE lesson: "Look Out Below For A UFO!"
LEARNING OBJECTIVES
Students will be able to:
--Simulate probability of an event occurring.
--Predict the probability of an event occurring, first based on prior knowledge and later based on data collected from the simulation.
--Apply language used to describe the probability of an event occurring.
--Analyze the intent of the makers of a video, including their intended audience and the scientific integrity of a clip.
--Worry less about the possibility of being hit by a falling asteroid!
MATERIALS
Two inflatable globes of the world
Two red markers
Two large pieces of butcher paper
Resource Sheet: Exploration Centers
PRE-VIEWING ACTIVITIES
Prerequisite knowledge: prior experience requiring prediction and
data collection, organization, display, and interpretation.
Students need a familiarity with ratio, percentage or fractions to be successful with this lesson.
Ask--Who saw or heard about that comet that came close to the Earth recently? Who watched a special about asteroids hitting the earth on TV recently? Did you know that the United States military is developing a weapon to deflect asteroids in case one comes close?
Continue--Who is at all afraid of being hit by an asteroid ? (Wait for a show of hands. Note number for later comparison. Discuss why or why not.)
Say--Imagine that an asteroid has just been spotted by astronomers entering Earth's atmosphere. Do you think it would be more likely to hit land or water?
Elicit several predictions. Encourage students to give reasons for their predictions. Indicate that almost no one has first-hand experience of asteroids hitting the earth-- we use our prior knowledge about an subject (geography) to predict an event.
FOCUS FOR VIEWING
Let's continue thinking about the possibility of an asteroid hitting the earth. I am going to show you computer animation of an asteroid hitting the Earth. I want you to guess where on earth (what biome or habitat if appropriate) the asteroid is hitting.
National Geographic video: "Asteroid: Deadly Impact".
START at the computer animation segment in the of an asteroid hitting a city with the sound off. (Segment appears immediately after the opening segment on Levy-Shoemaker 9.)
PAUSE halfway through and ask--Where is this collision taking place? How do you know?
START the video and STOP at the end of the segment of the asteroid hitting earth.
Ask--Do you think this is the most likely place for an asteroid to strike the earth ? Why or why not? Discuss.
POST-VIEWING ACTIVITIES
Say--We are going to try to determine if a city really is a likely place for an asteroid to land if one hit the earth. Usually scientists try to answer questions by doing experiments with real-life materials. But sometimes they can't, in which case they create a model and a simulation. Help students define "simulation".
Simulation: to create a model of; to take the appearance or form of.
Continue--We can't use real asteroids to see where asteroids might land, so we are going to do a simulation.
Ask students hold up their right index finger and place a red dot at the end of their finger with a red marker. Tell the students that the red dot represents an asteroid.
Divide the class in half. Have students form two large circles. Choose one student in each group to record the data and another student to count the number of trials. Students toss an inflatable globe around the circle. When they catch the globe, they note where their right index finger lands, water or land, and report the results to the recorder. Each group makes 50 tosses.
Monitor groups--stop them after a few tosses and discuss results. Encourage students to observe patterns that emerge as the number of simulations increase. Assist students in understanding that increasing the number of trials, helps them make a more accurate prediction.
It helps to have a parent volunteer or assistant with one of the circles. This activity works well outside on the playground.
After both groups are done, combine to make one group. Discuss and write up the results from each group. Add results from each group together so that you have statistics for 100 trials. Ask students to analyze the data and compare the experimental results with their predictions.
Students could research the actual percentages of land and water on Earth. Students compare their experimental results with the actual percentages of land and water.
Earth is approximately 71% water and 29% land--asteroids might hit water approximately 70 times and land approximately 30 times.
Repeat introductory question--Who is at all afraid of being hit by an asteroid? Wait for a show of hands. Discuss why or why not. Compare with earlier count. Are there more or fewer students afraid of asteroids now than before the lesson? Discuss.
REWIND video clip of asteroid hitting the earth. Focus for Viewing--Do you think that this video was made for scientists or for the general public?
PLAY and STOP at the end of the segment of the asteroid hitting earth. Ask--Do you think that this video was made for scientists or for the general public? Why? Do you think scientists helped make this video? Why or why not?
Assessment--Students write a "Special News Bulletin" for television to inform the public about a incoming asteroid. They should describe the situation and then advise viewers on the possibility of an asteroid hitting a house. Remind students that their bulletin should have words and numbers in their explanations. This could be done in class or as homework.
Collect student bulletins and evaluate them for understanding of simulation and probability.
ACTION PLAN
Write a letter to the makers of the video you viewed responding to the validity--or lack of validity--of the science on which it was based. Use the results of your simulation as an argument.
Talk to an astronomer or visit an observatory and ask how often: (1) they see an asteroid; (2) an asteroid makes it through earth's atmosphere; and (3) an asteroid hits land vs. water. You could also ask this question online at the website: "Meteorites, Meteorites and Impacts" at http://seds.lpl.arizona.edu/nineplanets/nineplanets/meteorites.html
Is an asteroid likely to hit a city? Use pictures of the earth from space taken at night to estimate the percentage of surface area lit up by artificial lights.
Use a coin to simulate an event that has two outcomes. Tell students they are going to take a test. Have students write 1-10 on their papers. Toss a coin. If it is heads, write "True", if it is tails, write "False". Have students number from 1-10 again.
Give questions on a topic students are studying and have them answer True Or False. Compare the results from the two instances.
Have students communicate the data they discover by constructing a table, chart or graph.
EXTENSIONS
Visit a website to find out more about where asteroids hit and about asteroids themselves if interested. Some good sites include:
"Meteorites, Meteorites and Impacts" at: http://seds.lpl.arizona.edu/nineplanets/nineplanets/meteorites.html
Mars Meteorite Home Page (JPL) at: http://www.jpl.nasa.gov/snc/
Individuals, groups or the whole class could develop questions for NASA engineers, scientists or mission planners about the simulations they are doing as part of the Mars Pathfinder (or other missions). The e-mail address is: question-lfm@quest.arc.nasa.gov
The Live From Mars website contains biographies and journals documenting simulations: http://quest.arc.nasa.gov/mars/teachers/eft/index.html
Students can research the probability of a meteorite striking North America. Students may use CD-ROM or text encyclopedia to research the actual land mass of each of the seven continents as well as the area covered by oceans and seas. Or they could focus on the land mass populated with concentrations of people.
Have the students participate in a series of centers to review probability. See Resource Sheet: Exploration Centers and accompanying "A Tacky Investigation" worksheet.
Use a game CD to inspire a discussion on the possibility of reaching level 5 or beating the dealer in Blackjack, or whatever the game requires.
Look up meteorites on the Encarta 96 CD-ROM Encyclopedia. Students could read the text with the following focusing question: "What mineral are you most likely to find if you analyze an asteroid? They are finished they should try to answer the question and give specific evidence from text. Hopefully they will point out that most meteorites are made mostly of iron, so that they would be most likely to find.
Bill Nye CD-ROM: "Stop The Rock" is an instructional science game about trying to stop an asteroid from hitting the earth. It provides an easy extension into other areas of science which students can do independently. Available from Pacific Interactive for $39.95 at the Channel 9 Store (206.682.8198).
