Title: Density of Wood Blocks

Purpose: To determine the density of a set of wooden blocks.

• To practice metric measurement
• To calculate using metric units
• To organize and graph data
• To determine density via direct calculate and by graphing
• To practice determining slope from a graph
• To calculate percent error

Materials:

• •set of wooden blocks
• •metric ruler
• •balance
• •graph paper

Procedure:

1. Measure length, width, and height of each block (to nearest .01 cm)
2. Determine mass of each block using balance (to nearest .01 g)
3. Calculate volume (V = l x w x h) of each block
4. Determine mean volume
5. Calculate density (D = m/V) for each block
6. Determine mean density for all wood blocks (this is the calculated value)
7. Graph volume (x-axis) vs mass (y-axis)
8. Draw a "line of best fit"
9. Determine slope of this line ( y₂ - y₁/ x₂ - x₁) (Use triangle method.....teacher will demonstrate)
10. Compare calculated value for density with that from the slope determined by triangle method.
11. Calculate percent error 3 ways: (A - O/ A) x 100%
    • using calculated value as "actual value" (A) and slope determined by triangle method as "observed value" (O),
    • using value provided by teacher as actual value and calculated value as observed value
    • using value provided by teacher as actual value and slope determined by triangle method as observed value
      

Results: (Observations and data~~~data charts and graphs and calculations where appropriate. Organization is necessary)

• data chart for measurements
• data chart for calculations
• graph of mass vs volume
• percent error calculations

Discussion:

1. Briefly summarize what you did.
2. Comment on measurement problems
3. Compare calculated and graphically determined slope values
4. Restate percent error
5. Comment on precision and accuracy of your measurements (remember the definitions of these terms!)
6. Comment on possible sources of error

The easiest conclusion to make from this lab is the wood density value.

Reflection:

• (A personal statement about the activity, whether it relates to "real life," whether you liked it, suggested improvements.....)