What can be more pleasant to a retired teacher than to plan lectures?
Here are my plans:
1) For a science course in elementary school:
Things like heights or weights are called of variables. Why? Because
they vary. Driving times, for example, from school school to homes are
also variable because different people live in different locations. And
driving from the same location can vary from day to day.
Instruments, such as scales, yardsticks and stopwatches are used to
measure variable. Let us collect variables (heihgt and weight) using
our scale and yardstick. John and Mary measure each student and I am
going to record the results in this table on the blackboard. Students
measure h and w and I am recording the results in two columns.
Then we would manually plot w versus h and h versus w. The act of
plotting should demonstrate that the shape of the relation (called
function in math) depends on the chosen scale. That is enough for the
very elementary introduction.
2) For a physics course in high school:
Go over the same introduction as above. Make sure they know that
variables in physics have names. In our labs variable are placeholders
for numerical information. Also make sure that functions (relations
between two variables) can be represented either by a two-columns table
or by a graph. Which variable (weight or height) should be placed into
the first column? It does not matter. And which axis (horizontal or
vertical) should be used to represent the first variable? It does not
matter. But once the choice is made the variable represented along the
horizontal axis is called independent. Why is it called independent?
Because mathematicians introduced this adjective. The other variable,
from any pair, is called dependent. Mathematicians will teach you much
more about functions.
3) That is about all. But how to make sure that this is remembered
later? By practicing. Subsequent lab activities can be used to review
the vocabulary, till things become obvious. This is not different from
other things, like absolute and relative errors, significant digits,
bars of errors, etc. Practice makes perfect. But we should not spend
too much time on trivial things like this. I suggest you assign manual
plotting in the first two or three labs (before jumping to Excel).
Ludwik Kowalski
Let the perfect not be the enemy of the good.