After Sharon's students worked on Toy Cars for 14 days in the fall, she returned to the topic three months later. Whereas the students had previously focused on the plastic toy car, now Sharon wanted them to try to understand the mechanisms underlying how other toy cars work: the key (or windup) car, the pullback car, the air (or propeller) car, the balloon car, the solar car and the electricity (battery-powered) car. She began by showing students some of the various cars and then asked them to work in groups to figure out how the cars worked.

Day 1

This first video clip shows Sharon introducing the new task that they will be working on over the next several weeks. Sharon had placed one of the cars at each table and wanted the group at that table to talk about how that car works.

Sharon spends the rest of the period moving around among the groups, listening and asking questions to help the group members explain how their toy car works.

First, she visits a table with Jennifer, Scarlett and Alexis. They are exploring the propeller (air) car, and in their initial explanation they use an analogy with the propellers of a ship.

Some things to notice: (click to hide)

Jennifer talks about the propeller (air) car. She says that as the propeller spins, the wind blows and that makes the car move. She draws an analogy with the spinning propellers on a ship in the ocean that make the ship move through the water.

Sharon returns to the same group about six minutes later to see what progress they have made. Jennifer's group has figured out how to make the car go either forward or backward.

Some things to notice: (click to hide)

Jorge and Jennifer have different explanations for what makes the car go either backwards or forwards. Jorge claims it has to do with how you position the car (aimed one way or the other), while Jennifer claims it has to do with the direction that you spin the propeller blades.

Sharon visits another group with Issac and Jimmy, who are working with the windup car. She asks them how it works and Issac talks about how the metal part ‘wants to twirl back.’ Sharon focuses on the word, ‘wants,’ and asks whether the car is thinking (like a person).

Some things to notice: (click to hide)

Isaac describes how he thinks the windup (key) car works. He says that when you wind it up, you make the (spiral) metal strip smaller, and then, after you let go, the strip tries to go back ('wants to twirl back') to its original size. As it goes back to its original size, it makes the car move forward. Sharon challenges Isaac on his statement that the strip 'wants' to twirl back, as if it were 'thinking.'

Sharon returns to the same group about eleven minutes later to see where they are in their thinking about the windup car. Issac tells her that, after winding, the coiled metal tries ‘to get back to its normal size.’ There is a long discussion about what that means. Issac gets a sheet of paper and rolls it up to help clarify his meaning. Jamir joins the group and tries to help out with the explanation. Sharon is persistent in trying to help the students offer a mechanistic explanation for why the coil unwinds.

Some things to notice: (click to hide)

Again Isaac explains the windup car by talking about how the wound coil 'tries' to go back to its normal size, and in so doing, makes the wheels turn and the car move. After Sharon presses him again on why the car 'wants' to do that, Isaac gets a sheet of paper to illustrate his idea. He rolls up the paper into a tight cylinder, just like the key rolls the metal strip into a tight spiral. Then he lets go of the paper cylinder and shows that it unwinds ('tries to go back'), just like the metal strip does. Again Sharon presses him for 'why,' and Isaac mentions it is like there is a person inside the cylinder, all squished up, who is trying to push his way out.
Jamir joins the conversation and talks about how this is like when you bend a metal, that the metal has a tendency to return to its normal size (shape). Sharon asks what other objects tend to return to their normal size, and Jamir says fat people can go running to try to return to their normal (skinnier) size.

In another group that Sharon visits, Pricila, Teresa and Maribel are trying to explain how a blown-up balloon pushes out the air when it deflates.

Some things to notice: (click to hide)

After the group says that the air coming out of the balloon pushes the car forward, Sharon pressed them on 'why' the air comes out of the balloon. The students could not provide a mechanistic explanation, but instead mentioned that the air 'wants' to come out of the balloon.

Sharon spends time with the group of Destiny, Jourdan and Jamir. She is asking them how the solar car works. Her focus here is both on clarifying the meaning of their words, and helping Jourdan stay focused on what Jamir is saying.

Some things to notice: (click to hide)

Jourdan says that when the light shines on the solar car and the wires are connected correctly, then electricity passes through the wires and makes the car move. Jamir then says that the light has electricity that passes through the plastic paper (solar panel) to the wires, that then make the wheels turn and the car move. [He indicates that the light has electricity because it got the electricity to make the car work.]

Summary for Days 1 & 2

Day 1