Transcript Objective Describe Kepler’s Three Laws of Planetary Motion

What do you notice about the Orbit of the
Planet’s compared to the Comet’s?
Aim:
Describe Kepler’s
Three Laws of
Planetary Motion
(eccentricity)
Which lane will Finish First?
Which lane has a shorter distance to travel?
+
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First Law: The planets
move in elliptical orbits
with the Sun at one focus.
Planet
Sun
Foci
What is an ellipse?
An ellipse is a closed curve around two
fixed points called foci.
Eccentricity- measures how stretched
out, NOT circular an orbit is.
Eccentricity= d (distance btwn foci)
L (length of Major axis)
Label the following:
distance between foci (d) and the
Length of Major axis (L)
E= 5.2cm = 0.419
12.4cm
d
+
Planet
+
Foci
Sun
L
Which planet has the roundest orbit?
Which one is the most ellongated?
Which planet moves fastest?
Which one moves the slowest
Which eccentricity is closest to Uranus?
Find the eccentricity of the following
Distance between Foci = 8.7 cm
Length of Major Axis 10.2 cm
Is this orbit more or less eccentric
as compared to the Earth?
1. Describe the relationship between
eccentricity of an ellipse and the shape
of a planet’s orbit
2. State the relationship between
distance between foci and eccentricity
of orbit.
Use the ESRTp.15 Solar System
Data Chart to answer the following:
Planet with the Least eccentric orbitVenus – 0.007 (Most nearly Circular)
Planet with the Most eccentric orbitMercury – 0.206
State the range for eccentricity?
0.000 – 1.000
Circle - Line
Second Law-Law of equal areas.
A line from the Sun to any planet
sweeps out equal areas in equal
time.
SUN
X-Y = 30 days
A-B = 30 days
A1=A2
X
A1
B
A2
A
Y
1. A planet must travel a longer
distance in its orbit from X-Y .
PerihelionPlanet is
closest to
the Sun
X
Y
SUN
AphelionPlanet is
B furthest
A
from the
Sun
2. For a planet to travel from X-Y and A-B in
the same amount of time it must increase its
velocity in orbit from X-Y.
3. It is winter in the Northern Hemisphere. The
seasons are caused by the Earth’s tilt on
axis. The Northern Hemisphere is tilted away
from the Sun during our Winter (January).
Appears
BIGGER
Closer
Perihelion
SMALLER
Farther
Aphelion
• Elliptical Orbits Interactive Animation:
http://www.windows2universe.org/physical
_science/physics/mechanics/orbit/orbit_sh
ape_interactive.html
Solar System
Fill in the data table using your ESRT
Name of Planet Distance from Sun
Period of Revolution
88 days
108.2
Venus
224.7 days
149.6
Earth
365.26 days
Third Law-The further a planet is
227.9
Mars
687 days
from
the Sun, 778.3
the longer its
period
Jupiter
11.86 days
of Saturn
revolution. 1,427
29.46 days
2,869
Uranus
84.0 years
4,496
Neptune
164.8 years
Mercury
57.9
1. Explain how a planet’s distance from the Sun
affects its period of Revolution.
Fill in the organizer below:
SUN
A
APHELION
Distance From the Sun
Earth’s location on the diagram
Season
Apparent Diameter of
the Sun
Acceleration in Orbit
Gravitational Force
Kinetic Energy/Potential Energy
C
PERIHELION