Lesson 3 of 10
Separating by weight
Show on a big screenA farmer tips a basket of threshed wheat into moving air. The grain and the husk land in different places. Threshed wheat is grain beaten loose from the plant. Husk is the light cover of each grain.
Loading lab…
Step 1 of 4
- A basket of grain and husk, mixed together.
- It falls through moving air.
- Heavy grain drops close, almost straight down.
- Light husk blows sideways and lands far off.
The rule
Winnowing — separating heavy grain from light husk with moving air.
Moving air pushes the light husk far to the side. The heavy grain is harder to push, so it barely moves.
needs two things: moving air, and a real gap in weight. A gap in weight means one part is much heavier.
Try the lab to finish this lesson.