G7 Week 12 – S2

Monday-Friday, May 1st-5th – All periods

Today in science: All periods finished watching the first episode of the BBC video series, Wonders of the Universe. This first episode, called “Destiny,” asks students to begin thinking not only about the idea of ‘cosmic’ time, a time scale that is infinitely bigger–or rather, longer–than our more familiar, human-based time scales (e.g., seconds, minutes, days), but also “entropy” or, as we preferred in class order/disorder.

The notes we collected for the first episode included:

A. 1 day = 24 hours = the time it takes for the Earth to complete one rotation (or spin) about its own axis.

B. 29.5 days = the time it takes for the Moon to complete one orbit (or circle) around the Earth.

C. 365.25 days = the time it takes for the Earth to complete one orbit (or circle) around the Sun.

D. 1 millennium = 1000 years

E. millennia = thousands of years

F. Our sun is one of 200 billion stars in the galaxy.

G. Our galaxy is one of 100 billion galaxies in the observable universe.

H. We have reason to believe that the universe is over 13 billion years old.

I. 2nd Law of Thermodynamics: Over time, things in the universe generally move from a state of (more) order to a state of (more) disorder. Another way of saying this is that entropy always–at least eventually–increases.

J. The remaining ‘life’ of our Sun is estimated at around 6 billion years, at which point our more ordered Sun will become a more disordered (dead! extinct! burned out!) Sun. 😦

K. The life stages of stars can be seen in the diagram below, but another diagram like the one we looked at in class can be seen here.

This diagram shows three different life pathways for stars (Image credit: http://www.enchantedlearning.com)

Homework: There is no science homework tonight or this weekend.