Announcements

• Prelim I is in 2 weeks!

• In-section review next week

• Assignment: send me 2 questions or concepts you want me to review by Sunday at 7pm – Email your questions to: shoshe@astro.cornell.edu

– This counts as 2 points of today’s section grade

– Also, homework is due next week

Homework

• Due in section – If you’re not in section on the day that homework is due,

you’ll lose 2 points for attendance

• All answers must be in your own words – This shows me that you understand the concepts

– Do not copy from the book

– Do not copy from the lectures/section notes

– Do not copy from a friend

Any questions from the past week?

Concepts from the past week

• Sidereal vs. synodic days and periods

• Seasons

• Phases of the Moon

• Tides

Image from http://en.wikipedia.org/wiki/File:Sidereal_Time_en.PNG

Sidereal vs. Synodic

Seasons

Image from http://visual.merriam-webster.com/earth/meteorology/seasons-year.php

How seasons work

Animated gif from http://deepimpact.umd.edu/disczone/braintwist-comet1a.html

Phases of the Moon

Tides I

Image from http://commons.wikimedia.org/wiki/File:Tidal_braking.svg

Tides II

Image from http://www.windows.ucar.edu/tour/link=/earth/Water/ocean_tides.html