SmithLab1

The tests allow for the AP students to learn how to use different tools for measuring objects. It also allows them to learn how to calculate the ratio between the Metric and English units of measurement. If the students measure and calculate the conversion factor between inches and centimeters then there will be less than a 10% error to the actual values because humans are know to make mistakes and the data can not be collected to a 100% perfect acount.  1 Ruler(cm/in)  1 Vernier caliper  1 Micrometer  1 Scale  1 Calculator  1 Cylinder (1.36 mass density)  1 Cylinder (1.36 mass density)  1 Steel ball (7.8 mass density)  1 ball (1.15 mass density)
 * Purpose/Background: **
 * Hypothesis: **
 * Apparatus: **


 * Procedure: **

Part C Part D
 * 1) Pick a metal cylinder. Use Vernier caliper to measure the length and diameter.
 * 2) Use the average radius and length and calculate the volume.
 * 3) Mass the cylinder. Record in grams.
 * 4) Calculate mass density of the cylinder. Compare to the accepted values in the density table.
 * 5) Repeat for the second cylinder.
 * 1) Use micrometer to measure the diameter of one sphere.
 * 2) Mass the sphere and record it.
 * 3) Calculate the mass density and compare to the accepted mass density.
 * 4) Repeat with a second sphere.

Cylinder 1
 * Data: **
 * Trail || Length || Diameter || Radius ||
 * No. || cm || cm || cm ||
 * 1 || 7.04 || 1.568 || 0.784 ||
 * 2 || 7.04 || 1.568 || 0.784 ||
 * 3 || 7.04 || 1.568 || 0.784 ||

Volume: 13.59 cm ²

Mass: 22.28 g

Experimental mass density: 1.639 g/cm ³

Accepted mass density: 1.36 g/cm ³

Error: .279 g/cm ³

% Error: 20.51%

Cylinder 2
 * Trail || Length || Diameter || Radius ||
 * No. || cm || cm || cm ||
 * 1 || 6.32 || 1.595 || 0.7975 ||
 * 2 || 6.32 || 1.595 || 0.7975 ||
 * 3 || 6.32 || 1.595 || 0.7975 ||

Volume: 12.628 cm ²

Mass: 25.61 g

Experimental mass density: 2.02 g/cm ³

Accepted mass density: 1.36 g/cm ³

Error: .668 g/cm ³

% Error: 49.12%

Sphere 1
 * Trail || Length || Diameter || Radius ||
 * No. || cm || cm || cm ||
 * 1 || 2.57 || 2.57 || 1.285 ||
 * 2 || 2.57 || 2.57 || 1.285 ||
 * 3 || 2.57 || 2.57 || 1.285 ||

Volume: 13.332 cm ²

Mass: 65.76 g

Experimental mass density: 4.93 g/cm ³

Accepted mass density: 7.8 g/cm ³

Error: 2.87 g/cm ³

% Error: 36.79%

Sphere 2
 * Trial || Length || Diameter || Radius ||
 * No. || cm || cm || cm ||
 * 1 || 2.53 || 2.53 || 1.265 ||
 * 2 || 2.53 || 2.53 || 1.265 ||
 * 3 || 2.53 || 2.53 || 1.265 ||

Volume: 12.719 cm ²

Mass: 9.85 g

Experimental mass density: .774 g/cm ³

Accepted mass density: 1.15 g/cm ³

Error: .376 g/cm ³

% Error: 32.66%


 * Analysis: **

The students needed to calculate the mean to find the mean volume of the objects.

mean=(n1+n2+n3...+nx)/x

mean=(2.53+2.53+2.53)/3

The experiment required the students to calculate the mean volume of the objects.

cylinder= πhr ²

cylinder=π6.32*.7975 ²

sphere=(4/3)πr ³

sphere=(4/3)π1.265 ³

The experiment also required the students to calculate the % they were off along with the numerical error.

%error= (|expected value-experimental value|/expected value)*100

%error= (|1.15-.774|/1.15)*100

error=|accepted value-experimental value|

error=|1.15-.774|


 * Conclusion: **

The hypothesis was not supported by the data. All experiments led to a %error greater than 20% which was higher than the predicted 10% or less error. One of the factors that might have affected the results were that the students read the measurements wrong on the caliper and the micrometer. Something that might be changed to make this more accurate is to use machines that can determine the precise readings so you will get a much closer %error if any at all.