Under the Microscope

Before the meeting:

1. Remind Cub Scouts to bring the leaf or needles they collected in requirement 1 and their tree inventory.
2. Gather supplies.
3. Set up meeting space with a flat space for microscopes.

During the meeting:

1. Gather Cub Scouts and explain the difference between deciduous or evergreen trees.
   1. Coniferous trees have seeds that grow in cones, which is where the word “coniferous” comes from. When a cone’s scales open, the seeds fall out, and new trees can take root grow in cones, which is where the word “coniferous” comes from. When a cone’s scales open, the seeds fall out, and new trees can take root. Most coniferous trees are evergreen, meaning they don’t lose their needles in the fall.
   2. Deciduous trees have wide, flat leaves that are good at capturing sunlight. They are called deciduous because most of them lose their leaves each year. Deciduous trees do not produce cones. Instead, their seeds are contained in nutshells or fruit. Oaks, maples, poplars, beeches, sycamores, and ashes are examples of deciduous trees.
2. Have Cub Scouts place the microscope directly above their leaf or needles at a 90º angle. Have the Cub Scouts turn on the LED light switch and begin viewing through the eyepiece.
3. Help Cub Scouts adjust the coarse knob or focus ring to fix the focus. Then, help them move the fine adjustment or zooming dial to focus up close and in higher magnification.
4. Give Cub Scouts time to make detailed observations. Have them check for:
   • Color. Is the leaf green? Has it started to change color due to the seasons?
   • Texture of the leaf. Is it smooth? Is it rough?
   • Edges of the leaf. Are they smooth or toothed?
   • Can they see the stomata on the underside of the leaf? (Stomata are tiny pores that open during the day to take in carbon dioxide and close at night to avoid losing too much water.)
   • Can they find the midrib and petiole? (The midrib runs along the center of the leaf and contains the central vein. It provides support to the leaf and ends in the petiole, the stiff stalk connecting the leaf to the plant stem.)
   • Unusual features on the blade (the flat part of the leaf made of green tissue which absorbs sunlight, making the sugar needed for the plant to grow). Are there holes from insects? Discoloration? Other damage?
5. Discuss with the Cub Scouts their observations. Using the tree identification resources available, have the Cub Scouts work together in small groups to determine if their tree is deciduous or coniferous.