Science Teams Activities

Procedure

The first research steps involved mapping the surfaces of the schoolyard. We mapped plant growth, such as grass, moss, trees, and foliage, as well as stone and hard soil. In another mapping exercise, puddles were included. Soil samples were taken at six different locations on our school grounds and adjacent areas.

After taking the soil samples with a spade, we filled the soil into plastic bags.

The soil at the different locations showed different plant growth. For example, one soil sample was taken from a meadow and another from a field with winter cereals. To determine the soil type, we used the app of the Geographical Institute of the University of Cologne. For this, the students answered the questions of an app. This app was specialized for soil types and at last the results came out: silty sand. clayey loam, silty loam and so on… later it even came out that the soil was not built naturally.

We conducted an experiment on the water storage capacity of soils at different locations in the schoolyard.
The questions of the experiment are: What percentage of precipitation does a) sealed surface b) soil c) meadow d) field store? What percent of precipitation runs off onto different areas of the schoolyard?

Description of experiment setup:

We took a bucket with 2.5 liters of water and filled it evenly for each experimental run.
We emptied the water in one pour briskly in a count of “21-22-23”. We conducted the experiment at the following locations in our school: sealed surface (basketball hoops near Borchert container), soil (soccer field), meadow (beach volleyball court), field (behind the fire department).

Results

Maps of the surfaces of the schoolyard:

Maps of the surfaces of the schoolyard with puddles:

Determinition of the soil samples from different locations 1 – 6

Site 1 back of the physics:
Mapping: moist

Sample description: small stones (ca.3cm), leaves, hard soil, crumbly

Result of the soil determination app: silty sand

Site 2 in front of A005 50.92648; 7.04791
Mapping: partial puddles

Sample description: roots, moss, small stones (3cm), small green plant, leaves, upper layer easy to dig and deeper harder to dig

Result of soil determination app: clayey silt

Site 3 on the soccer field
Mapping: rather dry

Sample description: first layer easy and at 10 cm difficult to dig; small stones (1-2 cm), grass with roots.

Result of soil identification app: silty sand.

Site 4 Meadow behind the Realschulcontainer

Mapping: moist, muddy, but no puddle

Sample description: small stones, grass, root firmly in soil, moist

Result of soil identification app: clayey loam

Site 5 at the volleyball court
Mapping: no puddles, soft, moist soil, normal

Sample description: soft soil, no rocks, leaves, grass, clover, moss = closed turf subsoil gave way, springy, sticky, but there was no soil on shoes

Result of soil determination app: silty loam

Site 6 in the field by the fire department

Mapping: no puddles, moist, muddy

Sample description: digging was easy, deeper there were old roots, compact and moist, small blades of grass, large sticky piece, no rocks

Result of soil identification app: clay loam.

Experiment: What percentage of precipitation runs off onto different areas of the schoolyard?

The execution of the experiment with the question “What percentage of precipitation runs off onto different areas of the schoolyard?” shows the following results. The observations on the sealed surface (basketball hoops near Borchert container) show that the water spreads about 1m and 5% of the water seeps into the cracks of the pavement.

On the ground (soccer field) the water spreads to about 1m and 50% seeps into the ground. At this location the soil is much more muddy and moist.

On the meadow (beach volleyball court), the water spreads significantly further than at the two previously described locations, at 1.5m. After 1 minute the water has clearly seeped away and after 2-3 minutes only 10% of the water is still visible as a puddle. The soil is also muddier and wetter at this location.

In the field (behind the fire station), the water spreads 1-2 m and quickly seeps away. 2 minutes later there are only 2-3 small puddles. Approximately 2l has seeped away.

Summary of the results

75% of the schoolyard is sealed surface, 20% is grass, 5% is bare soil. Where 0% of the precipitation that falls on the sealed ground is absorbed or stored by the soil. Accordingly, 100% goes to the sewer system and is not available to plants on site. 60% of the precipitation that falls on grass infiltrates into the soil and, accordingly, only 40% does not go into the soil but is discharged to the sewer system. Thus, most of the precipitation can be used by plants on site. 53% of the rainwater on the bare earth seeps into the ground. Accordingly, 47% flows into the sewer system. We calculated from these numbers that a total of 28% of the rainwater that falls on the schoolyard is absorbed by the soil. In order for more percent of the precipitation to be absorbed by the soil and available to the plants, there would have to be less sealed ground and more bare soil or forest in the schoolyard. However, this would then result in the possibility of slipping and injuring ourselves on the muddy ground.

Development Of The City Challenges

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