The first group tried to find out to which extent the four different soils could absorb water.
First, they put coffee filters in the flowerpots and filled them with different soil types. After that, they placed them in small tanks and filled the flowerpots with water. Over the span of 10 minutes, they monitored which soil absorbed the water best.
As suspected, their results showed that the terra preta-based soil absorbed the most water, while the one without terra preta absorbed little to no water.
The second group used the water and soil mixture from the first group to determine what kind of filter effect it had.
In order to do that, they prepared a colour and water mixture which would later be poured over the different soil types. This way, they could identify which soil filtered the colour best and worst. In the end, the terra preta soil performed the best.