“The search for the best garden” is a project organized during April 2022 with ten-year-old students from Primary School Mosa Pijade, located in Zagubica, Serbia with class teacher Zvonimirka Jovicic. The activity has interdisciplinary character and aims to make distinguish between favorable and unfavorable conditions for agriculture. Project is based on problem based learning, cooperative learning, experiential learning and student-led classroom.

There are many available, but not high-budget, teaching aids that have been used, such as: digitized material for testing hypotheses, digitized material for collecting students ‘opinions on activities, digitized material for exchanging students’ opinions, plant seeds, various types of land, jars, bottles, Coca – cola juice, ice cubes, syringe, cotton wool, ash, vinegar, kitchen salt and more.

The complex topic related to the environmental problems that humanity faces for ten-year-olds was presented through a series of experiments that they conducted, and based on the conclusions they reached, they gained knowledge about what a greenhouse is, how the greenhouse effect affects global warming, what salinization is and how it affects soil fertility, how soil enrichment can be increased slash and burn by using wood ash from burning wood (the area where the school is located is rich in forests and most households use wood for heating during the heating season).

The second part of the activity, in addition to the educational one, also had a creative character, and the aim was to find algorithms for the creative transformation of waste from the kitchen and classroom.

FOR OR AGAINST FACTORIES?

Students are motivated to work by reading an imaginary letter in which an unknown character asks for help regarding the dilemma “FOR AND AGAINST FACTORIES”, which is designed so that students state the reasons for building a factory in the village and reasons against building a factory in the village. It was used to exchange experiences linoit.

HOW DOES LAND DIFFER?

During the next stage, students get a new challenge and they are asked to give specific suggestions on the following issues:

• Should an investor who, due to the proximity of water, wants to start factory production on the site where the field plot is currently located, should be approved for such an endeavor?
• If starting production is still possible, what would be the most appropriate conditions for relocating crop production?
• Would such production be possible in other parts of the world?

The conversation concluded that it is necessary to examine how the proximity of the factory production affects the pollution of the environment, with special emphasis on the composition of the land that would be chosen for the continuation of the mentioned field production. In this regard, the students had the opportunity to learn how salinization occurs, but also how the increased concentration of CO₂ in the atmosphere affects the composition of the soil. In order to understand how salinization of the soil occurs, the students were given the task to add a solution of salt and water to the soil brought from a certain location, and then repeat the procedure several times after the water has evaporated. The students simulated acid rain by adding vinegar to the water.

The basic characteristic of such organized learning is setting a hypothesis at the beginning of each research activity and verifying or rejecting it at the end of the research.

During the next activity, students were given the task to perform the following experiment: put three different soil samples in three identical glass colorless jars: a mixture of soil and ash (first sample), soil taken from a garden near the school (second sample) and “saline” soil (third sample) which arose as a consequence of experimentally performed salinization. It was further necessary to put three beans in water, and after swelling, put one grain in each jar with tweezers so that you can see and follow its germination through the glass. Water the plant in another jar with a solution of vinegar and water as a simulation of “acid rain”. Follow for five days and record. Finally, a discussion was organized on which of the selected samples is the most favorable for plant cultivation.

During the observation, the following list (LINK) was used to record the observed.

During the next stage, students get a new challenge and they are asked to give specific suggestions on the following issues:

• The high concentration of salt in the soil adversely affects the growth of plants;
• Ash can be used to enrich the soil;
• The concentration of CO₂ in the atmosphere contributes to the global warming of the planet, which results in the warming of icebergs, which raises the level of the ocean and sea, which could destroy many settlements by immersion;
• “Acid” rains adversely affect plant development;

The tendency of the roots of the plant to germinate in the jar is proof that the plant needs water to survive, and the green shoot facing upwards is proof that the plant also needs sunlight to develop.

Along with this activity, students had the task to collect land from different locations and to investigate whether the soil differs in humidity and looseness, so the next experimental activity aimed to investigate whether soil moisture and looseness affect vegetable and field crops culture. We sowed one bean and one corn in two jars. This was followed by observation and recording of data for several days.

During the next stage, students get a new challenge and are asked to give specific suggestions on the following issues:

• Different types of land are different for different field and vegetable plants.

DIRTY AIR DETECTORS

In addition to selecting the type of soil with appropriate permeability and looseness, it was necessary to detect the location, and organized an activity called “Dirty air detectors” which included two interrelated (the procedure is described in the Google forms material) on which students concluded that the distance from the roads and the “distributors” of dust are the main allies in choosing the location to continue production.

• The production of field and vegetable crops must be away from roads and factories.

During the next activity, students had the opportunity to observe light permeability by noticing that greenhouses are covered with colorless nylons, while black nylons are used between rows to cover to prevent weeds from sprouting.

In addition to these activities, the students had the opportunity to explore how organic waste can be processed into compost and used to enrich the soil, on the one hand, and reduce waste at landfills, on the other hand.

In the second part of the project, students had the task to explore or independently design ways of creative use of waste from the kitchen and classroom. This activity was also used to develop algorithmic thinking because students were required to present the algorithm of making a certain subject in a few steps.