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5 THE COMPOSITION OF THE EARTH AND ITS ATMOSPHERE AND THE PROCESSES OCCURRING WITHIN THEM SHAPE THE EARTH’S SURFACE AND ITS CLIMATE
- Theory
- TASKS
- WORKSHEETS FOR PUPILS
Task 12b
Materials and tools for a working group:
picture of hydrological cycle in nature, larger plastic container or aquarium, clay, water, ice, 3 pcs plastic cup, food foil, stones. Alternatively, the teacher can use standard teaching tool representing Hydrological Cycle (or adapt it according to the pupil‘s suggestion).
The task of the pupils will be to design and create a water cycle in nature that they could realize in the classroom. The teacher first presents them a picture of hydrological cycle, in which they are to figure the movement of water in nature using arrows. Teacher discusses the sketches with them and asks for a justification (pupils should use findings from previous tasks). After the discussion, he asks the pupils to think about whether it is possible to create a water cycle in the classroom. She lets pupils discuss in groups, asking them to draw their predictions.
If pupils have a problem with this step, the teacher can present them with the tools they use to create a cycle in nature – i. aquarium (or transparent plastic container), clay, 3dcl plastic glass with 3 ice cubes, food foil to cover the aquarium (or microtene bag), plastic container (small – we insert clay), two small plastic cups, 3dcl plastic glass, 5 stones, water, rubber band.
Pic 64: Model of hydrological cycle
In the middle of the aquarium (large plastic container) pupils put one empty glass (we recommend to attach it with a melting gun to avoid overturning), put a small bowl in the corner, pour the clay (full 3 dl glass) ice and the bottom of the container laid four stones. Two 3dcl glasses of water are poured into the clay container and the aquarium is sealed with a foil (or microtene bag), which is attached with a rubber band. In this way, pupils can see various changes in water state – evaporation, melting, condensation.
The center of the foil will be loaded with a stone, which must be placed just above the glued empty glass. As water is evaporated and subsequently condensed on the top sheet, the water will drop into the glass at the location where the stone is placed on the sheet. The foil (bag) can be painted with a tempera color and allowed to dry before being placed in the aquarium.
After creating this model, the teacher discusses with the pupils what they think will happen to the water in the container. After the discussion, a teacher asks how they could speed up, or slow down the water flow into the glass. The task of the pupils will be to propose conditions that will speed up/slow down the water cycle. Also in this task, pupils should use findings from previous tasks.
Subsequently, pupils create the same models (the number depends on the number of conditions examined) and provide the proposed conditions. The teacher should be careful to always examine one variable so that they can clearly say what causes (accelerates/slows) conditions in the container. For example, when examining the effects of light, they should create at least two models, both of which will be exposed to the same temperature (eg on the window sill) and cover one of them with an opaque container. If they wanted to study the model at different temperatures (cold, heat), they can place one model on the windowsill and the other in a cool room. In this way, the teacher supports the development of the ability to objectively examine reality.
If the pupils have a problem with this step, the teacher can help them to propose the conditions (see worksheet).