Grade: Elementary
Subject: Science

#1459. How Old is that Tree

Science, level: Elementary
Posted Mon Dec 27 19:39:53 PST 1999 by Cindy Roter (
Hebrew Academy , Nassau County New York
Materials Required: A cross section of a tree or large branch. Masking tape, ruler
Activity Time: 20 minutes
Concepts Taught: Annual Rings, Tree growth rate ,environmental science

Explain to students the concept of annual rings. The rings are really a tubular system that carries water from roots to
top of tree. For every year the tree is alive it has another outer ring. In years with great precipation the ringd are further apart.

Also, if you measure the circumference of a tree in inches, one inch is approximately one year of age for the tree. 30
inch bark is about 30 years old etc.

First have students count the number of rings they see. Instruct them move to the widest areas if the rings has an indented circumference. Let each group come up with the number of rings.

Then to confirm the number of years, have students take masking tape and tape the entire perimeter of the treering. Cut the tape where the end meets the beginning. Carefully remove the tape and place it up on the black board. (using different colors keeps students awake, is more lively as and keeps the groups separate). Have students come up to the board and measure the tape with a ruler in inches. Every year a tree is alive is approximately one inch of circumference. How close were the annual ring count to the circumference measurement. Usually they are pretty close.
Look at the spacing between the rings and ask the children
where it rained the most. The students enjoy this truly hands on activity. Once you locate the wood rings you can use them for years.