Introduction
The chance of being
killed by an asteroid is about
one in 5,000 less than
that of being
killed in a plane crash. This is because an asteroid strike
could kill millions, whereas in a plane crash, the numbers are
small. No one has been hit in 1000 years. Some scientists
say earth is overdue. Link your students to the latest info about
earth impacts and try some related fun activities to increase
their understand of the next "big one."
Subject: Earth Science
Topic: Asteroid impacts
Grade Level: 9-12
http://berners.bcoe.butte.k12.ca.us/~clowrey/:
Standards
Addressed
Earth
Sciences
STATE
standard 1.f. Students know the evidence for the dramatic
effects that asteroid or comet impacts have had in shaping the
surface of planets and their moons and in mass extinction's of
life on earth.
S.J.U.S.D. standard 1.2 Some catastrophic events have caused significant changes on Earth.
S.J.U.S.D. standard 2.3 The universe is composed of a variety of objects governed by universal laws.
Instructional
Objectives
Using hands-on mini
labs students will gain an understanding of the effects of large
objects impacting the earth. The lesson will teach the
following
- Students will determine the mass of a 10Km asteroid by finding the weight of a one cm3 meteorite sample through displacement and multiplying the result by the number of cm3 in a 10km cube. Students will compare this weight to other large objects (Empire State Building for example) to gain insight into the incredible masses involved in asteroid collisions.
- Students are given the distance from the earth to the sun and use the orbital radius to find the orbital circumference by 2rxpi. Using this value, they determine orbital velocity in meters/sec to gain and understanding of the speeds involved in asteroid impacts.
- Students will drop, then shoot a small meteorite sample or rock using a slingshot(careful supervision) into a box filled with at least 4 inches of flour. Students will compare the size of the two craters to see the effect increasing velocity has on impacts and relate to the kinetic energy formula (K.E.=1/2mv2).
Students will
find the kinetic energy of a 10Km asteroid using the earth velocity
value and mass values determined earlier. By studying the
chart provided (see chart)students
can compare their energy value to that of explosions measured
in megatons.
Also, the lesson
will enable the teacher to engage students in cross curricular
activities.
(see
across the curriculum)
Student
Activities
Introductory
activities
The teacher can
begin the lesson by holding a globe of the earth and
throwing a grain
of sand onto the globe. Tell the students the sand granule
represents a 10Km diameter asteroid. Ask them what they think
the results would be of something so small (compared to the earth)
hitting the surface. Encourage a variety of answers. Also, if
available, show the opening from the CD IMPACT: GROUND ZER0.
Can be purchased at www.cdanddvd.com., or opening scenes from
10 seconds to impact video(TLC or Discovery Channel)
Enabling activities
1.Give
student(s) small meteorite or ordinary rock samples. Point out
that asteroids can be composed of heavy elements like nickel
and iron or be made of lighter sandy material. Have student(s)
determine the samples density in g/cm3 by displacement in a graduated
cylinder. Answers should vary from around 2 to 8 g/cm3, depending
on the sample. Next, have student(s) determine the number of
cm3 in a 10Km cube using LxWxH. (100cm=1m) x (10,000m=1Km) =
1,000,000 cm cubed = 1,000,000,000,000,000,000 cm3. Finally,
multiply cm3 value by mass gram value/cm3 found from displacement
and convert to Kg (subtract 3 zeros). Have students compare
to other large objects they're familiar with. They can
multiply by 2.2 to convert to pounds for a better understanding
of just how heavy a large asteroid can be.!
2.
Using construction paper or table white boards, have students
draw the sun in the middle with the earth approximately a foot
away. Provide or have them find the earths distance from the
sun (93 million miles) and convert to kilometers (divide by aprox..
.63) = 150 million Km. rounded off. Have students find orbital
circumference (dia. x Pi) = 300,000,000 x 3.14 = 942,000,000
Km. Divide by hours in a year (one orbit) for orbital velocity
= roughly 100,000 Km/hr or about
30
Km/sec = 30,000m/sec. (60,000 mi/hr). Point out that even
if the asteroid was not moving, the earth would slam into it
at tremendous speed. The fact that both are moving means collisions
can be much greater. Students can draw an asteroid heading
towards earth showing the velocity value.
3.Fill a large box with at least 4 inches of flour or light sand. Have student(s) drop their rock sample (waist high) into the flour. Drop another sample that is about twice as big from the same height. Have the students compare the craters. Second crater will be about twice as big as the first. Next, using careful supervision, have students(s) shoot the small rock into the flour with a standard or wrist slingshot from the same height. Now compare craters. This one should be much larger. May even form a central peak if the rock enters just right! Compare shape with moon craters. Have students determine why speed is more important than mass in creating large craters using the kinetic energy formula K.E. = 1/2mass x velocity2. Squaring the velocity number increases the energy four fold.
Culminating
Activity
Using
K.E.= 1/2mv2, have students find the energy of a 10Km asteroid.
Use the mass value (Kg)from activity one and the 30,000 meters
per second velocity from activity two. Answers should be around
a trillion trillion. Use scientific notation if it helps. 1/2
(1 x10 to the 15th Kg)x (9 x 10 to the 8th m/sec >30,000m/sec2).
This number is huge! Have students compare with energy
values given on chart showing various size asteroids and the
explosive force in megatons. Point out that an average
sized hydrogen bomb is around 10 megatons. Also, drop a one Kg
wt. from a couple of feet and ask students to catch it.
Now tell them to imagine a force a trillion trillion times greater
hitting them.
Across the curriculum
English/language
arts
Have students complete
the following: You (student) live 1000 years in the future.
The village elders have taught you that long ago a great disaster
struck the earth. They say that a spirit was upset with
humans and cast fire down from the sky. You believed them
when you were young, but with the rediscovery of a new instrument
(telescope) you are having second thoughts. When you look
at the moon you see large holes that look like they were made
from objects hitting the surface. You wonder if the same
thing happened to earth 1000 years ago. Write how you would
go about convincing the elders your idea has merit.
Life science
Connect the likely
explosion 65 million years ago to the idea of punctuated evolution.
Examine mass extinctions and their connection to core sample
fossils.
History
Evidence of a meteor
strike near Ireland in the middle of the 10th century may have
initiated the period known as the dark age. Several references
from that period mentions consecutive seasons without a summer
as well a strange skies as far away as china. Discuss with
students the impact physical earth change has on civilizations.
- 100% attendance for entire weeks activities
- Full participation and cooperation during mini labs
- All mini lab data spaces are completed correctly
- Student successfully answers related post test questions
3 Proficient
- 100% attendance for entire weeks activities
- Full participation during mini labs
- 80% of mini lab data completed correctly
- student correctly answers 75% of post test questions
2 Progressing
- 75% attendance for weeks activities
- Some participation during mini labs
- 50% of mini lab data completed correctly
- student correctly answers 50% of post test questions
1 Not meeting standards
- 50% or less attendance for weeks activities
- Little or no participation during mini labs
- Less than 50% of data completed successfully
- Student answers less than 50% of post test questions successfully
Results After implementing
your lesson (sometime between January & March), insert a
chart of your pre-test, post-test, and culminating assessment
data.
Chart
1. _50 meter diameter (Tungusta size impact) = 10 KT (Kiloton
=1000 tons of TNT) destroys a city. 2. __ 0.1Km diameter= 100
MT (megaton=1,000,000 tons of TNT) regional blunder, area the
size of Southern California destroyed. 3_______ 1.0 Km diameter
asteroid= 100,000MT, destroys a continent. 4. ________________________________________
10 Km diameter asteroid, 100,000,000 MT, Global disaster, mass
extinctions
Web Resources
& Supplementary Materials
1.
http://www.astronomy.com
School
Name: La Entrada alternative H.S.
School
Location: 5320 Hemlock st. Sacramento, CA. 95841
Clay Lowrey:
E-mail ClayandMadeline@aol.com
Last Revised:
06/30/2000 (insert
and update last revision date every time you work on this page.)