Look for: The skin on the foot stretches and moves as t…

2.A Analyze and interpret data to highlight the interactions between subsystems (skin, muscle, bone) within the larger system (foot or wing).

Students analyze a demonstration dissection of a chicken wing to make sense of how the different parts of the wing–specifically, the skin, muscles, and bones–work together for the wing to move. Their observations focus on visible interactions between these three parts and how they work together to support the wing’s function. Using their recorded observations, students will compare chicken parts with analogous human parts to make inferences about how the parts within the foot look and work together to move. Look/listen for these ideas:

• The skin on the foot stretches and moves as the foot moves up and down or back and forth, like the skin moved and stretched as the wing moved.
• The skin is attached to the muscle below it, which allows the skin to move when the muscles move.
• When the researcher pulls on the muscles in the upper part (upper arm) of the wing, the lower part (forearm) of the wing moves. For that to happen, the muscles in the upper part must be connected to the lower part.
• The muscles in the wing must be attached to the bones, because when the muscles are moved, the bones that are attached to them move also.
• When the bicep on the upper arm, or wing, is pulled one way, the tricep on the opposite side of the upper arm, or wing, straightens out. This makes the wing able to flex and extend.
• Although we cannot see them, we think the muscles and bones in the human foot work in similar ways to the chicken wing, because when the muscles move, the bones in the foot also move.

The class watches this chicken wing dissection to look more closely at the different parts. Some students may struggle with recording observations while watching. Make https://youtu.be/Sf9lI8K5GqE available to students to rewatch on their own outside of class so they have enough time to make sense of how the different parts look, move, and interact. Another option, if the technology is available, is to watch the video as a class once and then have students play it again in small groups on devices to make their observations. As an alternative to the video, if you have the time and materials, use Teacher Instructions for Chicken Wing Dissections to conduct a live demonstration for students to gather around and make their observations.

Say, Often in science as we try to figure things out, we use models or representations to help us explain a phenomenon. Sometimes those models look different from the original phenomenon. Here we used a chicken wing to figure out how the different parts in our foot work together for it to function. Would you say this dissection of a chicken wing is an appropriate and useful model for this purpose?

Student responses should be something like these:

• This model is mostly helpful. A chicken wing is different from a human foot, but because a chicken wing and human foot both have muscles, skin, and bones, we can figure out a lot about how these parts work together in the wing, and we think it is probably pretty similar in the foot from Lesson 1.
• We saw that the human arm and the chicken wing have similar parts (or structures), and the foot had muscles and bones that were injured, so it seems like there might be similar movement or function in the foot.