Wednesday, December 22, 2010

Angle Relationships - adjacent, supplementary, complementary

(1) Adjacent, Supplementary, Complementary, Vertical, Part 1- YayMath.org

Adjacent, Supplementary, Complementary, Vertical, Part 2- YayMath.org

(2) Complementary Angles - YourTeacher.com

(3) Supplementary Angles - YourTeacher.com

(4) Complementary and Supplementary Angles - TheFreeMathTutor.com

Angle Relationships - vertical

(1) Vertical Angles - YourTeacher.com

(2) Vertical Angles - TheFreeMathTutor.com

Parallel Lines and Transversals - Corresponding Angles, Same Side Interior, Same Side Exterior, Alternate Interior, Alternate Exterior

1) Corresponding Angles - TheFreeMathTutor.com

(2) Parallel Lines, Corresponding Angles, Transversal, Same Side, Alternate, etc. Part 1 - YayMath.org  (You can skip some if you want.  Watch 1:55-4:45, then 6:20 to the end.)

(3) Continuing on to Same Side Interior, Same Side Exterior, Alternate Interior, Alternate Exterior, Part 2 - YayMath.org

►Awesome interactive site!  Practice what you've learned.

Monday, December 20, 2010

Total Lunar Eclipse and Winter Solstice

There is to be a total lunar eclipse tonight, nearly at the same time as the Winter Solstice.  It has been 372 years since these occurred on the same day.  The Winter Solstice is the moment at which the North Pole is tilted the farthest away from the sun.  This is the shortest day of the year and the beginning of winter in the Northern Hemisphere.
These two events are unrelated, but they do not usually happen on the same day.
You can see the eclipse if you don't mind staying up awhile!
I'm telling my kids that if they want to stay up, then they have to look up some information first and tell me a few things they've learned, hee hee!
The moon starts into the earth's shadow at 1:33am EST and will be totally eclipsed from 2:41 to 3:53 EST.   This is when the moon will be red.
You lucky people in the Pacific Time Zone!  Your clocks will be three hours earlier than mine!
I hope I can stay up!  Maybe I need a nap.  Zzzzz....
Thanks to Apologia posting this on Facebook.

Total Lunar Eclipse on Aug. 28, 2007, seen from Kapiolani Park in Honolulu, Hawaii. Shot thru a telescope, about every 5 minutes.

Why does the moon turn red?  Simply put, it's for the same reason that sunsets are red.
White light is made of red, green, and blue. Our atmosphere filters out﻿ the shorter-wavelength light (blues, greens), so right on the edge of the earth's silhouette, the light from the sun that is hitting the moon is red.
If you were on the moon during a lunar eclipse, you would see a red ring around the silhouette of the earth.
The moon has no light of it's own and reflects whatever kind of light from the sun hits it.

--Last year in Physical Science, we did a very simple experiment (sheet of paper, red marker) that shows how the light spectrum works this way.  (Scroll down -- it would be the last one, of course!)

►At EarthSky.org, watch a video and/or read why "there won’t be a total lunar eclipse this far north on the sky’s dome until December 21, 2485."
Scroll down for specific times for different time zones.
►More information on Lunar Eclipses, including a list of future eclipses, and from what region of the earth they can be seen.  Scroll down.

UPDATE: Here is the eclipse from yesterday.

Winter Solstice Lunar Eclipse from William Castleman on Vimeo.

Sunday, December 19, 2010

Scientific Notation

(1) From standard form to scientific notation - YourTeacher.com

(2) From scientific notation to standard form - YourTeacher.com

(3) Scientific Notation I - MuchoMath (Professor Perez and Charlie)

(4) Scientific Notation II - MuchoMath (Professor Perez and Charlie)

Scientific Notation

Thursday, December 2, 2010

Long Multiplication a different way

I think this is an excellent way to teach multiplication.  The child can easily see that you are multiplying parts of a larger problem, then adding them together.