Hi.
At some point (maybe some on this list were 6 when this happened, but I have high school students that haven't reached this level upon their arrival in my classroom), students need to be able to identify a value based on:
How it might have been defined.
How it was measured.
How it was used (if someone else used it correctly).
The units of measure used to describe it.
If a kid can't do these things then they can't do much.
Speed - relate it to a car. How fast were you going? 30 miles per hour. Distance per time like km/hr, like m/s.
Acceleration- car commercials used to state 0-60 in 3.5 seconds. The commercials give you two speed values and a time value. While we often can't trust commercials, this is an instance when they are helpful.
As Joseph Bellina pointed out, the modeling method is also very helpful for describing the unit of measure for things like speed, acceleration, and other values.
90 second summary:
Kids take a distance vs time data form something traveling at constant speed.
Do it again (or have a different group do this) with something traveling at a different speed (but constant).
Plot the graph.
Ask (and it takes a while to get the right answer):
What does the y-intercept represent?
What does the steepness of the line represent?
Lets make an equation for this straight line motion.
Y=mx+b
Df=vt+Do
The first several times you do this it takes a bit of time and patience to get there. However, there is a payoff. Kids learn some physics, they learn the math. They learn the connection btn physics and math.
You can do the plotting in small groups or as a class. Sometimes it is helpful to do it as a class the first time. I've done circumference vs radius as a class then moved on to kinematics. It works well, but you need to stay patient and calm and help keep the kids calm.
Good Luck.
Paul Lulai
Physics Teacher
St Anthony Village S.H.
3303 33rd Ave NE
St Anthony Village, MN 55418
-----Original Message-----
From: phys-l-bounces@carnot.physics.buffalo.edu [mailto:phys-l-bounces@carnot.physics.buffalo.edu] On Behalf Of Rman Towndog
Sent: Wednesday, January 26, 2011 9:06 PM
To: phys-l@carnot.physics.buffalo.edu
Subject: [Phys-l] Any teaching tips
I'm teaching Physics (Algebra Based), we are learning about kinematics in 1-D.
I have students that have trouble listing knowns and unknowns. I tried to get
the students to learn the units (e.g. speed is m/s, etc), so they would know how
to do this step, but it's been largely unsuccessful. Any tips?