Labs Due Tuesday, HMWK for Wed

Today in class:
LABS DUE TUESDAY at the beginning of class.  If labs are late/not done/not in a lab journal / not correct they will not count for or against you; they will appear as an X in the gradebook, which is totally excused.  (this does mean that your grade will be based more on tests and homework, so don't think this is a free pass)

Due Wednesday:   Read p. 70-75; p. 75#1-7

Notes for Tuesday here

We had some notes/review on applied Algebra techniques.  Main Categories were:
Fractions --> specifically dividing by a fraction:  To simplify, multiply the numerator by the reciprocal of the denominator.

1 divided by (1/2)  is an easy example.  It is the same as 1 *  (2/1)  = 2.

This can be applied with letters and units as well as numbers;
A/(A/B)  = A * (B/A) which simplifies to just B  (easier to see if you rewrite the fractions vertically - hard to do on the computer)

Next was solving for an unknown; most of you are great at 2/3 of the problems we'll encounter in class.  The other scenario - many need a push.
Example:  You have the equation   Density = mass / volume.  Solve for Volume  (get v by itself).

I typically have people trying to multiply both sides by mass, which results in mass^2,  NOT what you want.

The solution for most people is found easily by making both sides into fractions:
Density / 1   =  mass / volume     (write it out vertically) and most people instantly see that they can cross multiply, resulting in Density * volume = mass,  and just one last step to get volume by itself.  :)


Third, we practiced checking equations by plugging in units; we solved s = d/t for t  (speed, distance, and time) and then plugged in hours, miles, and miles/hours to verify that hours on the left side of the equation equaled only hours on the right side (it did!)

Class was then cut loose to work to finish density labs, check floating or sinking in water, and work on a challenge/competition to get the best layering of different densities of colored saltwater.  One group got three distinct density colors to appear, most found a way to get two layers (and then verified it was density holding them there when they inverted the straw that was holding the layers!)