Save these instructions in your binder. Do not turn in.

## The Thickness of Al Foil and the Diameter of Cu Wire

Introduction

In science we must often make use of one set of measurements to indirectly measure other quantities. One example of this type of “measurement” will be found in this experiment. We do not have the equipment to directly measure the thickness of a piece of aluminum foil or the diameter of some copper wire. We can, however, measure length and width and calculate area. We can also measure the mass and calculate the volume using the density. Volume and area can in turn be used to calculate thickness.

Materials

Cu wire (d = 8.96 g/cm3)
Al foil (d = 2.70 g/cm3)
metric ruler
lab balance

Background

The following equations will make it possible to perform the calculations required by this lab:
density = mass/volume    D = m/V
volume = area x thickness    V = A × H
volume of a cylinder = π × radius of the base × height    Vcylinder = πr2h

Procedure

Prepare your lab notebook by putting the title of the lab and the date at the top of the first empty page in your lab notebook. Remember to make an entry in the table of contents and to number the pages as you go along. When writing in your lab notebook you should always say what you did, what you observed and what it means.
1. Obtain three Al foil rectangles which are at least 10 cm on each side.
2. Measure the length and width of each piece of Al foil in cm, estimating to 0.01 cm.
3. Find the mass of each piece of Al foil on a lab balance, making sure to record the maximum precision offered (usually to the hundredths place).
4. Obtain a piece of copper wire at least 20 cm in length.
5. Measure the length of the wire in cm, estimating to 0.01 cm.
6. Find the mass of the copper wire on the lab balance.

Data
Do not record your data here. Make tables like these in your lab notebook.

 Al rectangle 1 Al rectangle 2 Al rectangle 3 Length (cm) XXXX XXXX XXXX Width (cm) XXXX XXXX XXXX Area (cm2) XXXX XXXX XXXX Mass (g) XXXX XXXX XXXX Volume (cm3) XXXX XXXX XXXX Thickness (cm) XXXX XXXX XXXX Average Thickness (cm) XXXX
 Copper (Cu) Wire Length (cm) XXXX Mass (g) XXXX Volume (cm3) XXXX Radius (cm) XXXX Diameter (cm) XXXX

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Calculations
Perform the following calculations in your lab notebook and record the results in the data tables you made there.

1. Aluminum Foil
1. Calculate the area of each piece of aluminum foil.
2. Find the volume of each piece of aluminum foil using its mass and density.
3. Using the formula for the volume of a regular rectangular solid (V = L × W × H) find the thickness (height) of each piece of aluminum foil.
4. Calculate the average thickness of the aluminum foil.
2. Copper Wire
1. Find the volume of the copper wire using its mass and density.
2. Use the formula of the volume of a cylinder (V = πr2h) to find the radius of the wire (the wire is basically a very long, very narrow cylinder). The height of the cylinder is the length of the wire.
3. Calculate the diameter of the copper wire.

To Turn In

For this lab turn in a sheet of paper with your data tables neatly transcribed onto them. Show one sample calculation for each calculation you performed (area, volume, and thickness for the aluminum foil & radius and diameter for the copper wire). This work should be neat, easy to read, complete and should show all units. Report results with the correct number of significant figures.

Last updated: Oct 20, 2006      Home