Fourth Grade
Worksheets
Soil
The soil where you live might be very different from soil in other places. You might have noticed that soil can be different colors. Soil can have pieces of different sizes. Soil can feel very soft or very hard.
Soil is made of pieces of rock. If you look closely at a rock, you will see many tiny holes and cracks. When it rains or snows, water fills these holes and cracks. The water freezes and pushes against the rock. The rock slowly breaks apart. Over many years, the water causes rock to break into small pieces and form soil.
Soil also has air, water, and matter that was once alive. When plants and animals die, they decay. The decayed matter is called humus. It becomes part of the soil. This adds nutrients to the soil. Nutrients are materials plants need to live and grow. Humus gives soil a dark color.
When a rock breaks apart, its minerals become part of the soil. Some minerals can give the soil a certain color. The mineral iron can give soil a red color.
