Purpose

The purpose of this activity is for you to practice not only the measurement and calculation skills that you learned earlier in the unit, but also the problem solving skills that you have recently picked up as well.

Background

In science we often need to deal with very large, or very small numbers. We also need to be able to take our measurements and turn them into other quantities that are needed. Real scientists are oftentimes doing these things in situations that are new or novel. In order to solve these problems, it is important for scientists to understand how to go about problem solving. For this activity you will be using the method described in the Problem Solving in Physics Presentation.

For each of the activities below, you will be solving a problem using your own measurements. You will need to fill out the 5 steps of the problem solving approach for each.

Reminder of the steps:

1. DAP - Draw A Picture

It doesn't have to be beautiful, it just has to illustrate all the important aspects of the problem.Be sure to label any known dimensions or measurements on your picture.

2. KNU - list the Knowns aNd Unknowns

For the purposes of this activity, knowns are the quantities you can measure, unknowns is what you will need to discover.

3. EQN - pick the appropriate equations

Most of the equations that you will need for doing this activity come not from physics, which presumably you have not yet learned, but from simple geometry, mainly surface area and volume.

4. SSF - Solve Symbolically First

Rearrange and substitute equations from your list from step 3 so that you have just one equation solved for the unknown before you proceed.

5. CYA - Check Your Answer

Write sentence or two about why the answer you have developed seems reasonable to you.

As always, you will be graded on proper accuracy and precision in measurements and significant figures in calculations! Also all of your final answers should be expressed in scientific notation!

Activity 1: Arm Hair

How many hairs are there on your fore-arm?Hint:What geometric solid will you model your arm as?

DAP	KNU
SSF	EQN

Activity 2: Ping Pong Balls in the Room

How many ping pong balls could be packed into the room you are currently located in?

DAP	KNU
SSF	EQN

Activity 3: Steps

If it could be done. How many steps would it take for you to walk around the Earth at the equator?

DAP	KNU
SSF	EQN

Activity 4: Pencil Lead

How long of a line could you draw with a standard pencil, mechanical or not, depending on your personal preference. If you are using a traditional pencil, assume no loss of graphite due to sharpening!

DAP	KNU
SSF	EQN