1. The Solar System
How many words related to the solar system do you know? Complete a solar system word scramble! Using these 24 letters, ( don’t repeat them) try to come up with 10 words during this 5 minute warm-up.
M A N N T S Y O O L M E A D L G Y T S U P L R A N R T S M A N M E O R O O E X A A C O N E T N O O C S T L A T E R T I O I S E T

2. Planetary Motion Basics!
1) Please take out your IAN for today’s notes and your lab WS on seasons.
2) Fill out your agenda!

3. What is the connection? Gravity & Orbits Are they always perfect?
Do they always work in ellipses?
What could happen if a path is disturbed?

4. Sir Isaac Newton
1665
explained why the planets stay moving around the sun: inertia and gravity
1st law: inertia -a body will continue in a straight line unless acted on by a force.
Gravity keeps the moving planets in orbit around Sun

5. Newton Brainpop

6. Revolution Vs. Rotation
Earth rotates (spins) on its axis. One rotation per 24 hours
This is day and night.
Earth revolves around the Sun. One revolution happens every 365 1/4 days.
This one year.

7. Do it! Do it! Rotation When an object spins on its axis
Earth rotates once every 24 hours
Gives us day and night
Do it!

9. Solstices Sun is directly at 23.5° north or south latitude.
Summer (June 21) solstice has the longest daylight/shortest night in the Northern Hemisphere.
The winter solstice (December 21) is the shortest daylight/longest night in the Northern Hemisphere.
Of course these are reversed if you live in Australia!

10. Equinox
Solstice
Solstice
Equinox

11. Equinoxes Means “equal night.” Days and nights are equal in time.
Axis is not tilted towards or away from the Sun.
Sun is directly over the equator.
Vernal equinox (spring) occurs around March 21st.
Autumnal equinox occurs around September 23rd.
Again if you lived in the Southern Hemisphere these would be reversed!

12. Do it! Revolution When an object goes around another object
Earth revolves around the sun once every
365 1/4 days.
That is one year.= SEASONS!

16. Do it! Orbit The path an object takes around another object
Earth’s orbit is an ellipse.
Do it!

17. Inertia
An object in motion will stay in motion unless acted on by a force.
Baseball in space

18. gravity The force of attraction between two objects.
Affected by mass and distance

19. Gravity and Inertia Inertia is what keeps the planets moving in space.
Gravity is what keeps them moving around the sun.

20. Newton Brainpop

21. Modern Astronomy
The invention of the telescope and the description of gravity were two milestones in the development of modern astronomy.
In the 200 years following Newton’s discoveries, scientists made many discoveries about our solar system.
But they did not learn that our galaxy has cosmic neighbors until the 1920s.

22. What’s Next? The Big Bang again!