Experiences

Soil erosion

Aleksandar Angelov (center for creative education)

Bulgaria

High Secondary School

Maths, Biology, Science

Teaching in class

Direct

Aim: Provides information to students about the different types of soils and land, the principle of soil erosion and the influence of people activity on them.
Description: Students take soil, put it in a certain way in a cardboard box, pour water, monitor the process and draw conclusions.

Skills and key competencies:
• Basic knowledge of different types of soil
• Basic knowledge of soil erosion
• Communication in mother language
• Communication in foreign language / the lesson can be translated and led in a foreign language /
• Mathematics competence, basic knowledge of science and technology skills
• Study skills
• Initiative and entrepreneurial skills

Performance: this activity is performed best when students work in groups of 3-5 people.

Materials and Resources:
• Soil
• Boxes
• Moss, pebbles, sticks
• Pens
• Paper
• Coffee filters
• Large measuring bowls (beakers)
• Water
• Stopwatch

Stages:
Step 1: Students take soil from the garden close to school/schoolyard. Back in the classroom they put the soil in cardboard boxes in a certain way. No need boxes to be filled up to the brim with soil, layer of 10-20 cm is enough. Cardboard boxes should have holes on one of the sides, near the bottom (Figure 1). It is prepared three types of boxes with soil:
• In the first box the soil is just laid
• The second box is filled with soil mixed with pebbles, sticks and covered with moss
• The third box is filled with soil, which is terraced – like a staircase, where the lowest rung is at the hole in the box.

Step 2: When all groups are ready, their next task is to put the boxes inclined so that the side with the hole is lower than the opposite side. Then the students prepare for the next step – they put coffee filters on beakers, prepare their stopwatches and the water.
Step 3: Each group begins to pour water into the cardboard boxes. Water is poured slowly and carefully on the higher part of the box. The amount of water depends of the amount of soil, which is put in boxes. The beakers are placed under the hole in the box and when the water begins pouring students start their stopwatches. They stop them when the water stops flowing out of the hole.
Step 4: All data is entered in table - how much water there is in each beaker, how long it took to drain, is there sediment in the filter. Students compare their data.
Step 5: Discussion
How does a man influence on the environment?
Positive or negative do we influence on the environment?
What is soil erosion?
Key-TTT,ref.No504605-LLP-1-2009-1-BG-COMENIUS-CMP