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Author:
Jack Bauer

Student Exploration: Measuring Trees

Vocabulary: circumference, cross section, diameter, drought, growth ring, precipitation

Prior Knowledge Questions (Do these BEFORE using the Gizmo.)

Trees grow throughout the year. During which season(s) do you think trees grow fastest?

During which season(s) do trees grow most slowly?

What weather conditions could make trees grow more quickly than normal?

What weather conditions could make trees grow more slowly than normal?

Gizmo Warm-up

The Measuring Trees Gizmo™ shows part of a forest. Click tree E to select it. On the right side of the Gizmo, a cross section of the tree is displayed. Click Show larger view for a larger image.

The rings on the tree are called growth rings. Click Zoom in for a clearer view. How many rings can you count?

Click Return to forest, and then click Advance year once. How many growth rings are there now?

Click Advance year again and count the rings. How many are there now?

What does the number of rings tell you about the tree?

Activity A:

Measuring trees

Get the Gizmo ready:

∙ Click Return to forest, and then click Reset.

∙ Check that the Preset forest is shown (text at top). If not, click Refresh or Reload on your browser.

Question: How can you measure a tree?

Observe: Look at the trees in the forest.

Which tree do you think is the youngest?

Collect data: Measure each tree in the following ways. (Tree A has been done for you.)

Click the tree you want to measure. Estimate the height to the nearest tenth of a meter using the draggable ruler. (For example, the height might be 2.6 meters.)

Click Show larger view. Determine the age of the tree by counting growth rings. Use Zoom in as needed. (Hint: Do not count the bark of the tree as a separate ring.)

The diameter is the width of the tree trunk. Measure the diameter using the ruler. Write the diameter to the nearest tenth of a centimeter.

The circumference is the distance around the tree trunk. Click Find circumference to measure the circumference to the nearest tenth of a centimeter.

Analyze: How does the age of a tree relate to its size?

Extend your thinking: Compare the circumference values to the diameters. About how many times the diameter is the circumference?

Tutorial