Discuss the museum growth ring activities with students:
Gathering Tree Growth Data
Share group measurements of the different tree slices to complete the chart.
Tree Growth Data Chart (in PDF format)
What variations do you see?
Why are measurements different?
Compare drawings of the tree rings. Were there variations in where the measurements were taken? Why would this affect the measurement?
This is good reinforcement for the reasons scientists use multiple trials and replicate measurements, and describe the method of gathering data.
Ask students to enter their data analysis on-line to compare their data with others who have measured the tree rings.
Tree Growth graph (on-line - How fast did these trees grow?)
After students have finished the tree-ring chart have them try the online Ring Activity, where they will look at rings in both trees and dinosaur bones.
Tree Ring/Bone Ring Activity (link to on-line activity)
Douglas Fir Challenge Measurement
The challenge questions provide problem-solving opportunities and different ways to understand what tree ring evidence suggest about tree growth. A common student misconception in looking at tree rings is that more rings = faster growth. The width of the rings indicate the speed of growth over a growing period (most commonly over one year), so the wider the ring, the faster the growth.
Growth question 1
Where are the rings with the widest spacings?
Growth question 2
Students need to look at both the radius and the number of rings counted at that radius of both specimens.
Growth question 3
There are many creative ways to estimate the circumference of the giant Douglas Fir. The process is the most important portion of this question.
Actual Measurement: Douglas fir Circumference 682 cm