Leaching
Leaching is when water moves through soil and pulls out bits like plant food or dirt.
You set a strainer of cooked pasta over a bowl and pour water through it. The water drips down and carries tiny bits of starch and salt into the bowl. The pasta stays put, but the small stuff washes away. Soil works the same way — rain seeps through and pulls minerals down with it.
Explaining leaching by grade level
Think of rain on a pile of dirt. The water drips down and turns brown. It picks up tiny bits as it moves. Those bits end up in the ground below.
Projects that explore leaching
Leaching happens when water moves through soil and pulls out substances along the way. In this setup, water pours through soil mixed with dead plant material and drains into a lower can of pure water. The pH measurements show whether chemicals released by decaying vegetation have been pulled down into the water below.
Leaching happens when water moves through soil and pulls nutrients out as it goes. Here, water passes through fertilized soil and carries nitrate into the runoff trays below. The test kit results show that some fertilizers lose more nitrate to leaching than others.