Where, When, Why and How
RI.3.7
Read the text, then answer the questions.
How a Windmill Grinds Flour
A windmill turns moving air into turning stone. The sails are set at a slight angle. Because of that angle, wind pushing on them cannot pass straight through, so it pushes them round instead. The sails turn a horizontal shaft. A large wooden gear on that shaft meshes with a smaller one on an upright shaft, which turns the millstones below. Because the smaller gear has fewer teeth, it spins faster than the sails do. Four turns of the sails can mean twenty turns of the stone. The grain falls between two stones. The top stone turns; the bottom one does not. The grain is crushed between them, and flour comes out at the edge.
- 1. What would a diagram of a windmill need to label?
- 2. Put these in order: the millstones turn, the sails turn, the gears mesh.
Why Swallows Leave
Swallows do not leave Britain because of the cold. They leave because of the insects. A swallow eats flying insects, and it catches them in the air. In October the insects disappear, and a bird that eats nothing else has to follow the food. So swallows fly to southern Africa: about six thousand miles, taking roughly six weeks. They travel by day and feed as they go. They lose about a third of their body weight on the way. Many do not arrive. The following spring they return, and a swallow will often nest in the very barn it hatched in.
- 1. What would a map for this text need to show?
- 2. Put these in order: the swallows return, the insects disappear, the swallows fly south.
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