2nd Grade - Science

LESSON PROBLEM: Biology: How is rice harvested?


Rice is a cereal crop. After the rice farmer plants the rice seed, he has to wait for it to ripen. The warm sunshine helps ripen the rice. When it turns a golden color, it is ripe.

Like other cereal crops, rice must be harvested. The rice farmer must gather in the crop. It takes a lot of hard work to harvest the rice.

After the rice farmer plants the rice, he has to wait for it to ripen. The warm sunshine helps ripen the rice. When it turns a golden color it is ripe.

The rice has to be harvested at just the right time. If the grains are green when they are harvested, they will be too damp. The grains will rot if they are harvested too soon. If the farmers harvest the rice too late, it will be too dry and the grains will crack.

The rice harvest is done by hand or by machine. In the United States, machines are used to harvest the rice crop. They use a big machine called a combine harvester. Combine harvesters gather the rice from the large rice fields. The big machines cut and separate the rice grain from the plant straw. The large machine can harvest many acres very quickly.

Threshing is when the grain is separated from the rest of the rice plant. The combine harvester does the threshing. That is why it is called a combine harvester. Because it does two steps in one. It does both the harvesting (cutting) and the threshing.

Rice farmers very carefully plan the harvest. This is important to keep the rice at its best. Farmers need to know the exact time to drain the rice field and to harvest the rice. The rice cannot be too damp. The threshing cannot be too strong or it will hurt the rice grain. Care must be taken to keep dirt and leaves out of the harvested rice.

Once the rice has been threshed, it must be winnowed. Winnowing is when the chaff is taken from the rice. The chaff are bits of outer husk that cling to the rice. In the United States, machines do this job. The rough rice passes through a machine called a sheller that removes the husk. Brown rice is left. Brown rice has the bran layers still on the kernel. The grains of brown rice are milled by machines. The milling machines rub the grains together. The bran layer is gone and white rice is left.

Harvesting rice is hard work. Rice farmers must work very hard to harvest a good rice crop.


Make a Squishy Rice Ball:

You will need:

a balloon

1/2 cup of rice

a funnel


1. Place the end of the balloon over the funnel.

2. Pour the rice into the balloon.

3. Squeeze out the air that is left in the balloon.

4. Knot the end of the balloon.

You have a squishy rice balloon that is fun to squeeze.


Fold a paper into two parts. Draw the two things that the combine harvester does to help the rice farmer harvest rice. Write a sentence to go with each of your pictures.

  • ripen
  • harvested
  • machine
  • combine harvester
  • threshed
  • winnowed

Click here to play Rice Rampage!
Anatomy of Rice:
Rice is a seed of cereal (grass) plant used for food. Click here to learn more about the Anatomy of Rice.
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