**Scientific Methods Answer Sheet**

**Scientific Notation**

- Multiply: 3.1 x 10
^{7} by 3 x 10^{5}

- Multiply: 1.496 x 10
^{11} by 5.2

- Divide: (6.4 x 10
^{6})^{2} by 6.7 x 10^{-11}

**Measurement Errors and Uncertainties**

A. Measurement Errors
- Wavelengths:

- What is the uncertainty in your answer? That is,
how far off (in
*nm*) could your determinations be?

- How could you make your answer more precise?

- Blue and yellow:
yellow and red:
blue and red:
- Scale Factor:

- If you had a friend measure the distances,
would her/his results differ from yours? Why or why not?

B. How does an "accurate" measurement differ from a "precise" measurement?

C. Diameters of galaxies:

- What criteria did you use when determining each diameter?

- In determining the relative distances of these galaxies:
- Would it matter if you used a different criterion
for measuring each galaxy? Why or why not?

- Would it matter if one of your class mates used different criteria
than you did? Why or why not?

- Distances
- Which galaxy is the nearest? Farthest?

- How much farther away from us is the farthest galaxy compared
to the nearest?

- What assumption (stated above) is necessary for you to feel
confident your answer is correct?

**Statistics**

- Using a piece of graph paper, plot the magnitude (brightness) of the
star against its size.

- What is the slope of the line?

- Does the equation,
*y = mx + b* seem familiar?

- Do you see that for all future measurements, all we need to
do is measure the size of the star and use our relationship to
find the corresponding magnitude?

**Significant Digits**

- How many significant digits are in the following numbers?
- 1.5
- 3.5689
- 4000
- 3.68

- Multiply 1.5, 3.5689, 4000, and 3.68. Round your answer
to the correct number of significant digits.