# Physics & Physical Science Demos, Labs, & Projects for High School Teachers

## Posts Tagged ‘Unit Conversion’

### The First Two Weeks of Physics Class

Posted on: July 25, 2008

If you are new to teaching Physics, you are probably going to expect the students to know how to manipulate numbers and variables.  I’ve found that to be a big mistake.  Yes, some of my students are very good with math, but I’ve learned not to assume this.  As a result, my first two weeks of class are spent working on the skills they are going to use the entire year.  Those skills are:

• Scientific Notation
• Estimation
• Significant Digits
• Unit Conversions/Dimensional Analysis
• Solving for variables
• Use of their TI-83 calculators

This is a big post.  I have included all of the introductory worksheets, homeworks, and quizzes from the past school year.  A lot of example problems I just make up on the fly, but I have attached quite a few word documents.  Feel free to use them and adapt them as needed.

Scientific Notation

Last year I reviewed estimation first.  That was fine until we started dealing with very small numbers, then the students were lost.  This year, scientific notation comes first.  I have a three part handout that I go over in class.  I make up additional problems as we go, then I hand out the worksheet.  They start it in class and are expected to complete it for homework.

scientific-notation-notes-part-0

scientific-notation-notes-part-1

scientific-notation-notes-part-2

scientific-notation-problems

Estimation

The point of estimation is for them to be able to get order-of-magnitude answers quickly.  At first, they are completely amazed that I can get within 5% or 10% of the answer faster than they can do it on their calculator.  Some of them get good at this, most don’t bother even though they see that I will estimate quickly and accurately throughout the entire year.  My goal is for them to realize when their answer on the calculator can be wrong and their brain can be right.  It does happen and it feels good when one of them comes over to the dark side with me.

estimation-warm-up

estimation-worksheet

estimation-homework-quiz

Significant Digits

The first document is the handout they get with the guidelines.  I think it is rather clear, but I think I want to change the example problem near the end with the sin( ) function.  They don’t know sin( ) yet and it distracts them from the operation.  I expect them to use these guidelines all year long.

significant-digits

sig-dig-worksheet

Unit Conversion/Dimensional Analysis

Wow are they bad at this.  Most of them almost randomly multiply or divide by the conversion to get an answer but never seem to know if it’s right or what the units should be.  This is a real problem.  The textbooks like to throw different units into the problems.  It’s actually easy to miss, especially when the kids are struggling to learn a new concept.  I’ve also found that very few of them are comfortable with the metric system.  I feel like I beat this section to death, but still many cannot convert correctly.

warm-up-problem

unit-conversion-worksheet

Solving for Variables

I don’t have a worksheet made up for this section.  What I have done in the past is gone to an Algebra 1 textbook and copied the problems from there.  I gave up on this section last year, they just didn’t have the math skills to do this for every problem, and I had to choose my battles.  If they plugged numbers into equations, most of them were able to solve for the unknown.

TI-83 Calculator

Here is the problem; the students are unaware of the key labeled EE that does the scientific notation. They also constantly miss the exponent that is shown as 1.2E33.  Instead, they enter the number as 1.2 X 10 y^x 33.  This works fine if all they are doing is multiplication.  However, if they are dividing by the exponent, the 10 y^x 33 becomes part of the numerator.  This totally screws up their answers and they have no idea why.  There are two solutions:  1) They can use the EE function and only enter exponents in that form, or 2) they can use their longer form and put each term in parenthesis.  Obviously, I prefer the first solution and I push them to use it.

I also have them solve simple sine and cosine problems on their calculator.  Not all of them use the TI-83, I don’t require it, I only require a scientific calculator.  It’s up to them to know how to use it, that is why I spend time in the beginning going over the functions we will use in the course.

The Finish

I give them the following quiz after all of this is completed.

quiz

If you have additional material, please share it.  Trudi, I hope this helps.

### What’s New in 2013/2014?

Every year brings a change, this one is no exception.

I will be picking up the sophomore honors Algebra II class to keep them separate from the juniors. This should help accelerate them and put them on a stronger track towards Calculus. Looks like there will be only one section each of Physics and Calculus, but still two of Robotics & Engineering.

Hot topics this year are going to be the Common-Core Standards, Standards-Based Grading (SBG), improving AP Calculus scores, and somehow adding Python, maybe as a club.

### Polls in the sidebar

Just a quick poll to help me understand who is stopping by my blog.