**The Screw**

### Objectives:

Show that a screw is an inclined plane.

### Time:

One class time

### Materials:

paper

pencil

tape

crayon

### Prediction-Hypothesis-Question:

How do you make a screw?

### Procedure:

Give each group of students the materials.

Give each student a paper right-triangle and have the longest side
colored. Tape one of the uncolored sides of the triangle to the
pencil. Wrap the triangle around the pencil and tape down.

The triangle wraps in a spiral.

### Record Results:

Share their results.

The right triangle is an inclined plane.

**Conclusion:**

A screw is an inclined plane that is wrapped around a center
pole.

### Extensions:

Look at roads that zig-zag down mts. or spiral around them.

Which path is greater? The distance up the pencil or the length of
the edge of the triangle.

Take different types of screws and see how many turns it takes to get
the screw in a block of wood.

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