# Friday: November 8, 2013 - PowerPoint PPT Presentation

1 / 25

Friday: November 8, 2013. Science In The News. Daily Science Question pg 17. Describe the shape of a planetary orbit? What does it look like? Where is the Asteroid Belt located? By what planet?.

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

Friday: November 8, 2013

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

### Friday: November 8, 2013

Science In The News

### Daily Science Question pg 17

• Describe the shape of a planetary orbit? What does it look like?

• Where is the Asteroid Belt located? By what planet?

Learning Target (LT) # 6Kepler’s Laws of Planetary Motion 11/08/13_____________________________Cornell StyleWrite only underlined text from slides33

### Johannes Kepler

• Found patterns in planet movement; developed 3 laws of planetary motion.

### What are Kepler’s Laws?

1. Law of Ellipses

2. Law of Equal Areas

3. Law of Periods

### Eccentricity-

• The degree of elongation of an elliptical orbit.

1. Law of Ellipses: all orbits are elliptical, from nearly circular to parabolic.

e = 0e = 1

“e” is the eccentricity (how stretched to a max of “1”)

• Kepler’s second law states that equal areas are covered in equal amounts of time as an object orbits the sun.

• Both shaded triangles have the same area (think carpet).

• 2. Law of Equal Areas:

• Describes the speed of objects at different points.

• Objects move faster closer to perihelion and slower at aphelion.

### Orbital Period

• The time required for a body to complete a single orbit.

### Daily Science Question pg 17

• Kepler’s first law states that each planet orbits the sun, not in a circle, but in an ellipse. TRUE or FALSE

• Kepler’s law that describes how fast planets travel at different points in their orbits is called the law of ____________.

Learning Target (LT) # 6Kepler and Newton 11/12/13_____________________________Cornell StyleWrite only underlined text from slides35

### 3. Law of Periods

• Law of Periods:

• Relates the planets average distance from Sol to the time it takes the planet to complete 1 complete orbit.

• Measured in Earth years in distance of AU’s.

K x a3 = p2(K =1)

p = orbital period

a = distance from Sol

a3 = p2

Orbital periods measured = distance from the Sun.

Example: Jupiter’s orbital period is 11.9 Earth years

a3= p2

p=11.9

p2=142

p2=a3

a3=142

a=5.2

Jupiter’s average distance from Sol is 5.2 AU’s.

### How did Newton use this?

• Newton noticed that they also worked for all other objects. WHY?

• Inertia – tendency of object to resist change in motion unless outside force acts on it.

• But what force is causing the curve of the elliptical orbits, of a thrown ball, of a launched arrow…the apple falling from a tree?

• Objects in motion will stay in motion, unless…

Gravity is effected by distance and mass.

The closer the planet is to the sun, the stronger the gravity AND the faster the planet moves in its orbit,

### LSOpg 34

In Review:

• Kepler’s 1st law states planets orbit the sun in curved paths called ellipses

• Kepler’s 2nd law states planets closer to the sun travel faster than those further away.

• Kepler’s 3rd law relates a planet’s average distance from around the sun to the time it takes to make one orbit.