How are fold mountains formed?

The most common form of mountain ranges, like the Rockies, are fold mountains. How are they made?

Activity:

  1. Lay down a stack of towels, each one folded in half. If possible use towels of various colors.
  2. Put a box on either side of the towels.
  3. Push the boxes (continental plates) towards each other and observe the “mountains” being formed.

The boxes represent the continental plates while the towels represent the buildup of sediment on the sea bottom.

Question to ask:

What happens when the “plates” are pushed together? (The layers of sediment (towels) are pushed into folds).