VanCleave's Science Fun

Your Guide to Science Projects, Fun Experiments, and Science Research

ABOUT THE SOUND PICTURE

With mouth wide open, vibrating air coming up the throat from the vocal chords leaving the open mouth and spreading in all directions. Hi, I am Janice VanCleave, author of 50+ best-selling science experiment books for children ages 4 through high school. I taught science for 27 years and now am creating this science website.   My scream was not staged. The picture was to be of two adult cats, which I was holding. A microsecond before the camera snapped, the two cats dug their claws into my skin as they prepared to leap out of my arms. A picture like this is great for making inferences. Kids could make "guesses" as to why I am screaming. They would be drawing on facts from the photo, such as I look like I am in pain or maybe I am just pretending.

Sound Supplies and Sound Investigations

Educational Innovation Sound Supplies A black and yellow logo for Educational Innovations. A place to find fun science supplies.
Home » How to Make Paper Bridges

How to Make Paper Bridges

By

A Flat Paper BridgeA bridge is some structure that spans a gap. For example, in the diagram, the ends of the a flat piece of paper are placed on two books. The paper spans the gap between the book.

Instruction for making this Simple Paper Bridge are as follows:

1. Lay two equal size books on a table so that the books are about 6 inches (15 cm) apart.

2. Use one sheet of copy paper to make a bridge between the two books. Make sure that an equal amount of the paper lies on each book.

How strong is this bridge?

Paper Bridge TestingTo test the strength of the paper bridge, gently place one pencil at a time across the center of the paper bridge. The position of the test-pencil is shown in the diagram, but the diagram is not intended to represent the results. You must determine for yourself if the flat paper bridge will support the pencil.

If the pencil is too heavy for the paper bridge, remove the pencil, put the paper back in place, and then try objects with less weight, such as wooden toothpicks, paper clips, coins, etc…

Folded Paper Forms a BridgeDiscover for Yourself

Paper folded in the manner shown in the diagram increases the strength of the paper bridge.

Instructions:

1. Fold a sheet of copy paper  in half by placing the short ends together. Fold the paper in half again in the same direction.

2. Unfold the paper then bend it accordion style to form an M shape.

3.Use the folded paper to form a bridge between the books as shown. Again, make sure that an equal amount of the paper is on each book.

4. As before, test the strength of the paper bridge using pencils, or objects with less weight.

Why is the pleated bridge stronger? Because the weight of anything sitting on the bridge is spread out. Each of the peaks in the bridge frame spreads some of the weight down to the foundation. The more peaks, the less weight there is on one part of the bridge. Structural engineers design bridges so that the bridge structure spreads the weight of vehicles down to the foundation. Thus the bridge can support more weight.

Engineers must consider two types of forces on the bridge: compression and tension. For more information about structural forces, see Testing the Strength of an Egg.

2-M Shaped Paper BridgeScience Challenge

Look at the diagram. How much stronger is this 2-M shaped bridge than the 1-M shaped bridge previously tested?

7182X: Janice VanCleave"s Engineering for Every Kid: Easy Activities That Make Learning Science Fun Janice VanCleave’s Engineering for Every Kid: Easy Activities That Make Learning Science Fun