ScienceSource.ca Dry Lab Activity

Unit C - Chapter 8

Investigating Science 10

Quick Lab

Tree Cookie Tales

A tree trunk holds a great deal of history - as environmental conditions change they are often recorded in the growth pattern of the tree. By studying the growth patterns in a tree trunk, a long history of environmental conditions can be revealed.


Purpose

What can tree cookies reveal about the past?


Materials and Equipment

  • tree cookie
  • coloured pencils
  • ruler
  • hand lens
  • calculator

Dry Lab

A "dry lab" activity includes collected data and/or a video solution for your convenience. You can simply watch the following video and use the provided data, or if you wish to perform this lab for yourself, follow the procedure steps 1 through 6 described in the video. The same steps are included in written form in the documents available for download on the bottom of this page.



Questions

  1. A student performing the procedure steps 1 through 6 recorded the following numbers when measuring the tree cookie. Use these numbers to calculate the percentage of the tree's growth that took place in the first 10 years of its life.

    From Pith to Centre (radius)

    5.5 cm

    From Pith to 10th Annual ring

    2.0 cm



    How do you think that percentage compares to the growth of the tree over its entire life? Explain.

  2. Environmental disasters can show up in tree cookie evidence. How might a grass fire, flood, or extremely cold growing season show up in the tree cookie evidence?