I ring my chime to get the class’s attention and ask them to return to the carpet squares and ‘Show Five’. Once seated, I announce that we are about to begin the fifth Science lesson in our unit about trees. To engage the students, I often start the lesson with a question because it provides quick engagement and sets a positive and collaborative tone. I refer to the cross section specimen (or picture) we used in a previous lesson, “Who can point to the part of your body that hold everything together?” When I saw no answers, I gave another clue. “This part makes sure that all our body gets all the blood it needs to survive.” “Our bones?” “It’s our skin! Take a minute to touch your skin. Touch it and press gently down. Can you see how it turns whiter, then red again?” “Yesss!” “Woah!” “A tree’s skin is called bark. Let’s explore more about this important part of the tree.”
For this lesson, I re-introduce a book titled Tell Me, Tree (As you can see, it’s such a great resource that I’ve used it in several lessons!). It has a few pages on tree parts that focus on bark..a little bit. I feel strongly that it’s an important subject to teach so I press on. Despite my research, I had a difficult time finding kid-friendly resources. When this happens, I work to design a lesson that that provides an appropriate amount of material, albeit not as much as in other lessons (which just goes to show that , sometimes, simple is just fine!). I review the pages, highlighting the parts that refer to a tree’s structure. “We just showed in our book that a tree’s skin is called…” I touch the skin on my arm as a visual cue for the students, particularly the English Language Learners. “Bark!” I review this terminology to deepen the experience. I keep it to one Science concept to keep things simple.
“How many of you have ever touched the bark on a tree?” A few hands went up. “How many of you have ever scratched that bark.” No hands went up. “I’m so glad to hear that. Want to know why? Because the bark is what takes all the sap- that’s like the blood of a tree- to the different parts of a tree. What parts do you think needs it?” “Trunk?” “They do. Anything else?” Roots!” “Leaves” “All those things need sap to continue to grow. Each year, the tree adds another layer of new bark and creates another whorl. The old bark stay inside the tree to provide support and grow the tree out.” As we go over these tree parts that use sap, I briefly refer to the KWL chart so the students can access prior knowledge and give valuable context to the new material.
As I give this instruction, I hold up the cross section piece from the Hook and point to the different whorls as I move my finger toward the outside to illustrate this concept. “Trees have layers?” “They do! The important thing to know is that it’s the outer layer that carries that vital sap to the rest of the tree. When people scratch, carve, peel, or cut the bark, it creates a scar- like the kind you get after an injury. Then, the sap can’t get to the parts of the tree that needs it. Imagine of your blood couldn’t get to your body parts?” “That would be sad!” “I agree. When people do things like that to trees, the tree can give very sick, sometimes even die. That’s why it’s so important to learn about trees, look at them, examine them, and study them closely. Then we wan to to protect them, not hurt them.” While I don’t want to scare them, I do want to help them understand the important of nature stewardship. “It’s our job to protect the nature around us. How would you like to go outside and explore some of the tree bark in our playground?” “Meeeee!”
• Bark samples (either separate samples or attached to a tree will work!)
• Paper for rubbing
As a review, I briefly go over the tree part we discussed. “We learned that trees all have bark. This bark is different for every type of tree, with a different color, appearance, and texture. Like we saw in the book, it’s one of the ways that dendrologists can identify different kinds of trees. We’re going to go outside and make a rubbing of three types of trees. This will help us explore and differentiate -tell the difference- the trees that we see every day. Since they’ve been sitting a while, I dismiss them to line up and plan to finish the instruction outside.
We walk outside to the playground. I show them a trifold worksheet with three sections for each bark rubbing. I pass out one to each student, along with some dark crayons (black & brown show the most detail and look authentic), and begin the direction:
• First, locate a tree with bark that interests you
• Next, put your paper on the tree and hold it with one hand
• Then, use the other hand to rub the bark with the crayon
• Last, press hard enough with the crayon so you can see the pattern of the bark!
The process the students take to create their tree rubbings takes about ten minutes. As the activity winds down, I give them a one-minute warning with a hand clap pattern. I ask the students to take their papers and crayons and return back to class. Note: Real life models are crucial to helping develop and concrete understanding of Natural Science. If you don't have access to living trees, I'd highly recommend (again!) visiting a local arborist or craft person to get some samples. It's worth the time!
Once we are gathered, I ask the students to put the crayons in the box and take their papers to their carpets squares. I want to take a minute to both the material and extend it with a little Math. “Can anyone see a pattern in your bark rubbings?” A few hands go up. “Why don’t do take a minute and share your paper with two of your friends around you. Look to see if anyone has rubbings with similar patterns.” This step is short by design because the intent is to give the students an additional opportunity to process and describe their model to partners, thus making the material more concrete. Once this step was complete, I again rang the chime and asked the students to put their papers in their bag and return when they were finished.