Answer from the Text
W.1.8
Read the text, then answer the questions.
How a Bridge Stands Up
A bridge has to hold its own weight and the weight of everything crossing it. The simplest bridge is a beam: a flat piece laid across a gap. A beam bridge cannot be very long, or it sags in the middle. An arch bridge is curved. The curve pushes the weight out to the ends, where the ground is solid. That is why arch bridges can cross wider gaps.
- 1. What shape is an arch bridge?
- 2. Why does the author say arch bridges can cross wider gaps?
- 3. What does "sags" mean here?
- 4. What happens to a beam bridge that is too long?
Why Tall Buildings Do Not Fall Over
A tall building needs a wide, deep base. The base is called a foundation. It spreads the weight into the ground. Wind pushes hard on a tall building. Inside, a strong core of concrete runs from the bottom to the top like a spine. The core stops the building bending too far. The tallest buildings sway a little in strong wind. That is meant to happen. A building that could not bend at all would crack.
- 1. What runs from the bottom to the top inside a tall building?
- 2. What do the tallest buildings do in strong wind?
- 3. What is the base of a tall building called?
- 4. The author says swaying is meant to happen. What reason is given?
LessonPrint · W.1.8 · Set 21 · free to copy for classroom use