| 摘要 |
PURPOSE: A teaching tool is provided to teach absorption rate of carbon dioxide of a tree according to a growth period and to teach whether the absorption rate of the carbon dioxide of the tree is higher than a reference or not. CONSTITUTION: An annual ring indication part(11) which indicates an annual ring corresponding to age of a tree is formed on the upper surface of a stump model(10). The age, type, and diameter of the tree are printed on the bottom of the stump model. A circle width tape measure(20) measures circle width of the stump model by protecting the outer circumference of the stump model. The circle width tape measure indicates a circle width value which multiplies circular constant according to radius on one side of a string at a constant interval. |
