Rocket tapes two paper towel tubes into a bike frame. It folds in half. "Oops!" he laughs.
Raven tilts her head. "What do you notice about the frame in our picture?"
Rocket counts. "Lots of tubes, all joined together!"
Nova hovers near the handlebars. "A frame holds every other part," she says. "How do the wheels join it?"
Rocket grabs more tape and tries again.
The frame is made of tubes. It holds all the other parts together.
The top tube runs along the top.
The down tube runs from the front down to the pedals.
The seat tube holds the seat post.
The saddle is the bike seat. It lets the rider sit on the bike.
The seat post slides into the seat tube. It holds up the saddle.
A clamp locks the seat post so it cannot slip down.
The handlebars let the rider steer the bike.
The fork holds the front wheel.
The fork passes up through the front of the frame to the handlebars.
So when the handlebars turn, the front wheel turns too.
Super looking! Tomorrow we roll on to the wheels: hub, spokes, rim and tire.