1. Building a Comet! (An excuse to play with dry ice.)

2. What’s the difference between a comet and an asteroid?

3. Comets are “beautiful objects.”

4. “Ooooooooooh”

5. “Aaaaaaaaaaaaaah”

6. Asteroids are kind of ugly.

7. ...and sometimes they hate us.

8. (Best movie EVER.)

9. -Chunks of rock that orbit the sun between Mars and Jupiter -Most are small pebbles; a few are larger than New Mexico -Can be seen as meteors, or “shooting stars” Asteroids:

11. NEWS FLASH ASTEROID TO HIT EARTH IN 2022! An asteroid was discovered that's on a near-collision course with the Earth - and could crash into us in 2022. Astronomers have been monitoring the path of the giant space rock since it was spotted on January 28, 2000. http://www.thehollywoodgossip.com/2013/03/cosmic-crash-2022-asteroid-to-go-boom/

12. Meteorite impact in Russia, February 2013

13. Shoemaker Levy 9 meets Jupiter July 1994

17. Crater chain on Callisto (One of Jupiter’s moons.)

18. Energy from impacts... - Speeds of ~65,000mph - Meteorite the size of a football field → 1000 atomic bombs - Dinosaur-killing meteorite: ~6 miles wide - A little bigger means a LOT more energy 10 times bigger → 500-1000 times more energy Side note: velocity = SQRT(2 * 9.8 m/s 2 * height)

19. Comets: -Dirty snowballs (rock and ice) -Long-period comets from the Oort cloud -Short-period comets from the Kuiper Belt -100,000 km in diameter with really long tails (2500 x Earth’s circumference)

21. Diagram of a Comet

24. Making a Comet! - Make craters in flour - ½ cup of water - 1 or 2 spoons of sand -- stir well - a little ammonia and a little organic material - crushed dry ice stir “vigorously” when adding the dry ice (but don’t tear the plastic bag) - a little more water – shape your comet