lab2
.docx
keyboard_arrow_up
School
Western University *
*We aren’t endorsed by this school
Course
2232
Subject
Astronomy
Date
Dec 6, 2023
Type
docx
Pages
7
Uploaded by nehakamath on coursehero.com
ES 2232G: Exploring the Planets: Sun, Earth, Planets
Laboratory 02 – Planetary Atmospheres
(Materials reproduced from the Astronomy Education at the University of Nebraska-Lincoln Web Site
(http://astro.unl.edu).
INTRODUCTION
This lab explores some of the elements that go into the retention or loss of an atmosphere by a
planet. Open a web browser and point to:
http://astro.unl.edu/naap/atmosphere/atmosphere.html
.
Work through the background sections on Escape Velocity, Projectile Simulation, and Speed
Distribution. Then complete the following questions related to the background information.
Question 1:
Imagine that asteroid A that has an escape velocity of 50 m/s. If asteroid B has twice
the mass and twice the radius, it would have an escape velocity ______________ the escape
velocity of asteroid A.
a)
4 times
b)
Twice
c)
the same as
d)
half
e)
one-fourth
Question 2:
Complete the table below by using the Projectile Simulator to determine the escape
velocities for the following objects. Since the masses and radii are given in terms of the Earth’s,
you can easily check your values by using the mathematical formula for escape velocity.
Object
Mass
(Mearth)
Radius
(Rearth)
v
esc
(km/s)
v
esc
(km/s) calculation
(optional)
Mercury
0.055
0.38
4.3
0.055
11.2
4.3
0.38
km
km
s
s
Uranus
15
4.0
21.7
√
(
15
)
(
4.0
)
(
11.2
km
s
)
=
21.1
km
s
Io
0.015
0.30
2.5
√
(
0.015
)
(
0.30
)
(
11.2
km
s
)
= 2.5
km
s
Vesta
0.00005
0.083
0.3
√
(
0.00005
)
(
0.083
)
(
11.2
km
s
)
= 0.3
Earth Sciences 2232G: Lab 02
1
km
s
Krypton
100
10
35.4
√
(
100
)
(
10
)
(
11.2
km
s
)
= 35.4
km
s
Question 3:
Experiment with the Maxwell Distribution Simulator. Then a) draw a sketch of a
typical gas curve below, b) label both the x-axis and y-axis appropriately, c) draw in the estimated
locations of the most probable velocity v
mp
and average velocity v
avg
, and d) shade in the region
corresponding to the fastest moving 3% of the gas particles.
Maxwe
ll Speed Distribution
Earth Sciences 2232G: Lab 02
Number of Particles
Average
Velocity
Most probable velocity
Particle Speeds
Fastest
3%
2
GAS RETENTION SIMULATOR
Open the
gas retention simulator
. Begin by familiarizing yourself with the capabilities of the
gas retention simulator through experimentation.
The
gas retention simulator
provides you with a
chamber
in which you can place
various gases and control the temperature. The dots moving inside this chamber should be
thought of as tracers where each represents a large number of gas particles. The walls of
the chamber can be configured to be a) impermeable so that they always rebound the gas
particles, and b) sufficiently penetrable so that particles that hit the wall with velocity over
some threshold can escape. You can also view the distributions of speeds for each gas in
relation to the escape velocity in the
Distribution Plot
panel.
The lower right panel entitled
gases
allows you to add and remove gases in the
experimental chamber. The lower left panel is entitled
chamber properties
. In its default
mode it has
allow escape from chamber
unchecked and has a
temperature
of 300 K.
Click
start simulation
to set the particles in motion in the chamber panel. Note that
stop
simulation
must be clicked to change the temperature or the gases in the simulation.
The upper right panel entitled distribution plot allows one to view the Maxwell
distribution of the gas as was possible in the background pages. Usage of the show
draggable cursor is straightforward and allows one to conveniently read off distribution
values such as the most probable velocity. The show distribution info for selected gases
requires that a gas be selected in the gas panel. This functionality anticipates a time when
more than one gas will be added to the chamber.
Exercises
Use the pull-down menu to add hydrogen to the chamber.
Question 4:
Complete the table using the draggable cursor to
measure the most probable velocity for hydrogen at each of
the given temperatures. Write a short description of the
relationship between T and v
mp
.
Temperature is a measure of
kinetic energy. Increasing the temperature, in turn increases
the kinetic energy and increases the probable velocity for
hydrogen at high temperature. Conversely, decreasing the temperature decreases the kinetic
energy and decreases the probable velocity of hydrogen. So the relationship between Temperature
and Vmp has a positive correlation.
Earth Sciences 2232G: Lab 02
3
T (K)
v
mp
(m/s)
300
1555
200
1250
100
895
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
- Access to all documents
- Unlimited textbook solutions
- 24/7 expert homework help