Task 4

Materials and tools for a working group:

Concept Cartoons© – Shadows, shapes cut out of different materials, torch

Similarly to Task 1, in this task, pupils are encouraged to discuss suggestions for explaining the commonly observed phenomenon. The task guides pupils to think about whether shadows can overlap and create darker shadows. Pupils already know that there are lighter and darker shadows, but the question is whether darker shadows can arise by overlapping objects and thus by overlapping shadows of these objects. When presenting a picture to pupils, it is important to note that the question is not focused on shadow density (if two trees with a small number of leaves overlap, the shadow at the point where they overlap will be more coherent). It is appropriate to explain to the pupils that the situation should be conceived as if we were covering two leaves of the trees, and it is not clear whether they are the leaves of the same tree or different trees.

The first task will be to decide (in groups) which statement they would consider true. At the same time, the teacher leads the pupils to try to justify their claim. As in the first task (Concept Cartoons), it is important here to devote sufficient reasoning to the pupils. These should be based on their previous experience and be presented in a logical way. If the individual groups do not agree on which statement expresses the fact, the teacher encourages them to try to convince the other group with their arguments (previous experience that supports their decision for a particular statement).

If they agree (usually the pupils agree more or less that the place where the trees overlap will not be darker), the teacher will provide the pupils with materials to explore the shadows. At this stage of exploration, he does not yet provide pupils with leaves from trees, but cut out shapes in the form of sheets of different materials, some of which do not permeate light at all, some are partially translucent and colored (for example, sheets cut from colored foil). The aim of this investigation is to provide a possible lack of experience on how shadows are formed when overlapping and translucent materials overlap. Among other things, pupils find that it is possible to create colored shades with transparent colored foils.

After the examination, the teacher leads them to read the statements in the picture again and to consider which one could be true, respectively, when (in what conditions) every of the statements would be true (by overlapping what materials the shadow of the shadows is dark, the darker shadow and the two times the dark shadows). The result of the discussion should be a generalization that a darker shadow occurs when we overlap two translucent materials (light-transmitting materials).

However, this is not yet the answer to the original question. Therefore, the teacher leads the pupils to comment on the predictions in task 4b (Leaves of trees do not pass light and therefore do not create a darker shadow when covered). By formulating the statement, the teacher creates a pattern in predictions. The task of pupils is to express their consent or disagreement with such a formulated prediction. Consequently, the teacher leads the pupils to try to suggest a procedure by which they can see if the leaves of the trees are translucent (not transmitting light). It will give the pupils in the groups enough time to devise a procedure that is sufficiently trustworthy and convincing (it will unequivocally determine whether or not the light gets through the leaves). They present their designs to each other and choose the one that will provide the most convincing results for implementation. Part of the preparation for exploration is also writing a set of tools to learn how to plan their own research activities better.

The most obvious is the transparency of materials, pupils shine at sheet from a certain (even zero) distance to see if light is visible through the material or not. Subsequently, they observe diverse leaves, either on the samples brought by the teacher; on house plants in the classroom or outside in the school yard. The teacher can also encourage pupils to try (within homework) to find leaves that do not let the light go. The result of their investigation will be the discovery that the leaves of the tree are light transmitting. Consequently, they can return to the original call (Concept Cartoons method) and state which statement is in line with reality.

An important part of the activity is the creation of a conclusion. The conclusion is formulated by pupils in group interaction. The teacher directs them to include an assessment of the prediction and an answer to the original research question that emerged from the picture.

What pupils have found in this research task is going to be applied in task 4c. Their task is to create a prediction of what material and color it is appropriate to make umbrellas. The teacher directs the pupils to try to use the results of the research from previous tasks (for example, that under dark materials is warmer, translucent materials do not produce as dark shadow as non-opaque materials, etc.). Therefore, in addition to the prediction itself, the leaders of the leadership are also required to justify their predictions with the conclusions of previous research investigations.

Task 4c represents the form of open inquiry, only the research challenge is given, and the pupils make predictions, and the procedure itself, how to verify the predictions. Given that this research challenge is based on a prior examination of the relevant phenomenon, it is possible to ask pupils to make predictions, justifications and suggestions for a process to verify their predictions within homework and to discuss in class discussions with them what they have designed and are looking for the best way to verify their predictions.

Subsequently, the investigations will be realized and the research problem will be evaluated in the form of a conclusion. Again, it is important to point out that the conclusion must include, in addition to assessing the predictions, the answer to the research question, in which case it is a statement of what materials are appropriate for the construction of the umbrellas. The conclusion of the investigation should be substantiated by the outcome of the investigation. This means that pupils should indicate on the basis of what they claim. In doing so, they learn to argue facts and thus carry out an objective investigation.

At the end of the set of activities, which are focused on shadow research (tasks 1–4), it is advisable to discuss with the pupils what new they have found. In principle, pupils find out how the shadows are formed, which leads them to realize that light does not get beyond the objects, creating shadows, places behind objects where there is less light than around. The teacher asks the students what they think is happening with the light when it falls on the objects. Also, in the previous investigation, they found that if the object is dark in color, the light causes the objects to heat, i. it seems to be turning into heat. It is not the case with bright objects. Therefore, in the next set of activities, they will explore what is happening with light when it hits shiny and bright surfaces. Pupils will examine how the light behaves when it hits the mirror. In addition to finding the basic rule of light reflection from flat surfaces (creating aobject image in the mirror), pupils also find that light is responsible for seeing objects. For example, if objects are around the corner, we cannot see them because the light travels through the space straight and so the light reflected from the object around the corner does not have to get into our eye and so we do not see it. It is precisely this influencing of materials with light that is very important for the development of this key theory (a great scientific idea).