Why Bridges Stand Up
Every strong thing people build hides a clever idea inside it — and you can find those ideas.
Have you ever wondered how a heavy bridge can hold up cars and not fall down? The secret is a shape called the arch. An arch is a curve that spreads weight out to the sides instead of letting it push straight down in one spot.
You can test this yourself. Lay a flat sheet of paper across two cups and set a coin on top. The paper sags and drops the coin. Now bend the paper into a small arch between the cups. This time it holds the coin without bending.
Builders have used arches for thousands of years. Old stone bridges in Rome still stand today because of them. A good shape can be stronger than a lot of extra material.
Tap any word to hear it.
Retell it: what is the topic, and what are two things you learned?
Say it out loud first, then type a little. Retelling is the real reading skill — this gets saved to her report.
What is the main idea of this passage?
In the test, what happens when you bend the paper into an arch?
How do you know arches are a very old idea?
Answer all 3 questions to finish. 3 of 3 right and it’s hers.