Introductory Activity :

Duration: 30 minutes

Description: This activity will help students better understand the many properties of wood. Students learn how plywood is made.

Goals: National Science Education Standards (NSES):

1. Science as Inquiry; Abilities necessary to do scientific inquiry - Students develop simple process skills necessary to scientific inquiry, such as how to observe, p. 122.
2. Science and Technology; Abilities of technological design - Students evaluate a product or design and include oral, written, and pictorial communication of the design process and product, p. 137-138.

Body :

Focus Phase:
Hold up a plywood sample and ask students, "How do you think this kind of wood is made?" Allow them to examine other kinds of wood and discuss how they are different. Interview students concerning their thoughts on how plywood might be constructed. Determine the students' "best thinking so far." ["Our Best Thinking So Far" is a way to assess students' prior knowledge about the topic -- what they know at this point.]

Challenge Phase:
Show students a popsicle stick and ask them to compare it to the plywood. "How are they alike? How are they different?" Challenge students to see if they can break a popsicle stick (Can be done, with a little help!). Next, challenge them to try to break a piece of the plywood sample. (They won't be able to!) Allow students to experiment using more than one popsicle stick to form layers. "What happens as more layers are used? Do the popsicle sticks become harder or easier to bend? What does this tell you about how plywood might be made?"

Concept Introduction:
Confirm that plywood is made from thin layers of wood glued together. Introduce the word laminating -- this is the process of gluing wood together to form plywood. Reinforce the way in which plywood is formed by completing the "sandwich wood" activity. Show students how to glue their three pieces of wood together to form layers. Ask students, "How did layering change the durability of the wood?" (made it much stronger) Reinforce the similarities between sandwich wood and plywood by having students compare them verbally. Then have students draw a picture of each in their science journals. "How are they the same? How are they different?"

Concept Application:
Give each student one graham cracker. Tell them that you want to take this cracker in your lunch to school, but you're afraid it might break in your backpack. Using graham crackers and the chocolate frosting, ask students to come up with a way that the dessert will be stronger and more likely to make it to noon. Ask students to explain how they can use what they've learned about layers and strength in wood to solve this problem. Enjoy the treat!

Conclusion Activity :

Special Comments: "Sandwich wood" is a term coined by the Full Option Science System: Wood Module , from which this lesson is adapted. The term is intended to describe the layered nature of the wood that students create, much like putting together the layers in a sandwich.

Vocabulary Words :

• Plywood - A type of wood made from thin sheets of wood that have been glued together.
  
• Laminating - The process of gluing layers of wood together.
  
• Grains - The arrangement and direction of particles in a piece of wood.
  

Evaluation Activity :

Students will be evaluated by using a simple checklist to check for the following:

1. Skills: gluing, pressing
2. Processes: observing properties of strength in wood, comparing sandwich wood and plywood, communicating similarities and differences orally and through pictures
3. Concepts: demonstrate an understanding that the layers in plywood make it very strong

Internet Resources Referenced in this Lesson :

National Science Education Standards
FOSS (Full Option Science System)