Solar System distances, math practice, quiz tomorrow.

HMWK:  Study for quiz tomorrow - chapter review pages on 212-215 should be a pretty good review of most of the concepts we've learned so far, and you will also have a math problem relating gravity and astronomy or distance/speed  and astronomy.  

Today: discovery of the asteroid belt and Neptune, mean distances from the Sun, in A.U. are:

0.39, 0.72, 1.0 (Earth), 1.5, 2.8 (asteroid belt), 5.2, 9.5, 19.2, 30, and just for Raven and Paige in 4th hour, 40. = pluto  (these are slightly more exact than the original predictions were)

I will give you these values to use on your tests; you need only know how to use them.

Asteroid belt was predicted by a numerical sequence, Neptune was found due to its gravitational disturbance on Uranus.

The practice problem(s) we worked today working with speed, distance, and time AND these astronomical units should be pretty relevant for your quiz; you will have either something dealing with speed and distance in the BIG scale of our solar system or you will have a question dealing with gravity.

Astronomy - gravity and its effects

notes from today
hmwk due tomorrow!

**I misspoke in a couple of classes today regarding greatest and smallest tides; the sun adds to the moon's tides during a full or a new moon, making these tides the greatest; and when the moon is at first or third quarter, forces are at right angles to one another and the tides are at a minimum**  I will note this in class tomorrow as well.

New HMWK, due Thursday

Hmwk for Thursday:  Read p. 197-207, p. 207#1-6

Today:  Practice with scientific notation and sig figs
Finish notes on seasons and moon, started notes on our sun.

Sig figs recommended practice here

Other astronomy review (some we haven't covered yet)
problems 1-6,12,14,16,18,21,23-25, 27-34

another here with sig figs and astronomy.

2-18 - 2-25 Sig Figs practice, Moon & Seasons, optional assignment

New optional assignment:  Provide photographic evidence that YOU (not a copy of someone else's work) can balance an egg on its end, or a broom on its bristles, in February (which is NOT on the equinox!)
Email photos to Freeman or share in class for points; 10/10 for one egg or broom balancing, and additional points up to 15/10 will be awarded for additional challenges; several eggs, eggs on their skinny ends, etc.
Please share with your friends as "any day of the year" egg balancing.  Turn in no later than midnight this Friday, March 1.

Today we watched a recently popular video by an astronomer-photographer; Full Moon Silhouettes, and had notes regarding seasons, moon brightness, and a few other related topics that should help clear up any misconceptions about what causes seasons.
Get a copy of notes here.

We also discussed answers (in most classes) to the significant figures and scientific notation practice worksheet (problems #1-8) and how you would go about solving 9 and 10.

Sig Figs!!! Hmwk now due Friday

Notes: Significant figures - why they're important, why scientific method is used: 
Accuracy vs. precision - accuracy is how well a tool is used; an error in accuracy is caused by the user and can be corrected. precision describes the degree of measurement; is the tool measuring relatively large quantities, or is it measuring using tiny increments? When we combine measurements, we can assume that the result is only as precise as the least precise measurement that went into calculations. 
Rules for reporting significant figures: 
all nonzero digits are significant. ex: 123,456 m 
Zeroes are significant when they are between nonzero digits. 5054 L 
Zeroes are significant when they are to the R of decimal and to R of nonzero digits. 12.00m 
Zeroes are not significant when they are to the L of all nonzero digits. .000345 cm 
Zeroes are not significant when they are to the L of decimal and to R of all nonzero digits.200 m 
The last example shows a problem which arises when measuring something that comes out to an even number; if this is measured to the nearest meter, how can it be reported as such - as written, 200 could mean that the degree of precision is only the nearest 100m. 
--> Enter Scientific notation. 2.00*10^2 = 200, but the zeroes are now significant. 
We also started a practice w/s on sig figs; will finish tomorrow in class.

Tomorrow's topic:  (finishing new practice with sig figs), Our perception of time on the Earth, seasons, and Earth's Moon's phases vs. eclipses

Geocentrism vs. Heliocentrism, HMWK, gravity

Today we finished our old-school thinking debates; this one was for evidence supporting Geocentrism vs. Heliocentrism.  Most classes found that the Geocentric view does have more everyday-type evidence; the Heliocentric arguments are tough unless you know a bit about planets or ways to estimate size and distance in space.
We had a reading discussing problems with geocentrism, namely retrograde motion of planets that appear (from Earth's point of view) to move backward during some period as we watch them move day-to-day across the sky.
Answers to homework were discussed and some classes moved on to discussing tomorrow's notes on gravity and significant figures.  We'll probably also start with some more interesting discussion of seasons and  misconceptions about Earth's slightly elliptical orbit.

HMWK for Thursday:  Read p. 190-195, p. 195#1-6.
remember, optional assignments (see last week's post) are due on Friday!

Electromagnets, exam, new unit, optional assignments

We worked to make electromagnets this week in class and reviewed electricity and magnetism concepts.
Labs are due on Monday.

Our test on E&M was today (Friday).  Grades should go online this afternoon.

Our next unit is Astronomy; HMWK is to read p. 185-189, p. 189#1,4-6.  Due Tuesday.

I apologize for not posting optional assignments toward the end of this unit; here are two that I will allow until next Friday, the 15th.

Electric Field hockey game

Faraday's experiment