Task 6

Materials and tools for a working group:

torch, colored sticky papers (to mark points on the wall), mirror, material and tools designed by pupils (probably boxes of juice, scissors, mirror, plasticine, scissors, adhesive tape, mirrors, etc.).

The sixth task is to explore how light is reflected from the mirror. Among other things, pupils find that light goes straight through space and can be diverted by objects that reflect light more than they absorb. In task 6a, the teacher guides the pupils to mark four points according to the drawing in the task. If the room is wide and the light source (flashlight) does not reach the other wall, it is advisable to replace the second wall with, for example, a vertical canvas or a board. It is the task of the pupils to point the flashlight to point 1 and try to redirect the light through the mirrors so that the flashlight shines progressively to points 2, 3 and 4. First, the pupils think hypothetically and make predictions. They try to plot how many mirrors they need and where and how to place them. Subsequently, they try to confirm their thinking about this situation by practical implementation of the situation.

Pupils draw the observation into the second column. By comparing the predictions with the result of the observation they formulate a conclusion, which includes a description of how the light behaved during the journey through the space. Pupil answers may vary, the condition being that the conclusions drawn are based on the observations they have made and are consistent with the findings. Subsequently, the teacher discusses with the pupils whether it is possible to look around the corner without a mirror, leading them to another research task.

In Task 6b, pupils focus on how periscope works. First, the teacher discusses about pupils prior knowledge about periscope – where it is used, how it works and whether it has ever been used. Then they focus their attention on the picture, where a simple periscope is shown schematically. The task of the pupils is to think about how the image (in principle, the light carries (represent) the image) of the object gets into the eye of the person when using the periscope in the way they see in the picture. In the periscope scheme, they try to indicate where the light travels and how it is reflected from the periscope mirrors. The aim of the task is to show the students the principle of periscope operation in a way through which they perceive how the periscope must be constructed.

Pupils express their own understanding of the periscope function by solving a partial task in which they are asked to mark the objects behind the wall, which the observer will see by such a periscope (they refer to some of the following: flower, tree and its parts, cherries in the tree, spider web and spider, ants and butterfly). The pupils will then be able to mark the selected objects under the picture. After an individual (or group) solution of the task, the teacher and pupils discuss their solutions, thus creating a research question for further research. The teacher asks the pupils to try to make the periscope out of the available materials and to see if they will only see some items or all that is behind the wall.

In the task 6c, pupils create their own periscope. In addition to finding out how to construct it to see behind the wall, over water or around the corner, pupils also find out whether a person (or his eye) can be seen in the periscope, watching us if we look into the periscope of the opposite sides (see Figure 6c). We reserve enough space for pupils to design their own periscope, or we will ask them to think about the design within their homework. If a teacher wants to help pupils to create a periscope, they can push some suitable materials, such as boxes of juice, scissors, mirror, plasticine. More activity develops the pupil‘s scientific thinking when he / she has to think about what different tools he / she will need. They have to think not only about the basic construction materials (mirrors, suitable box), but also about the tools for the treatment of these materials (scissors etc.) and about the connecting materials (egplasticine, adhesive tape, etc.).

Pupils create periscope. They modify it until it is functional. Subsequently, they use the created periscope to verify what they can see when they lift it above the wall (for example, whether it is possible to see objects that are just below the wall). They then also see if they are seen from the other side of the observer. The teacher will use the results of this observation to explain that light is reflected in the periscope reflected from the objects we see. If the object is not straight ahead of the periscope, we do not see it because the light reflected from this object does not reach the periscope. Pupils can try to explain why to see the eye of an observer in the periscope if we look at it from the other side. They will record what they have learned to be essential to the periscope design (when it works and when it no longer works). For example, periscope mirrors must be parallel to each other and below.

Pupils apply the result of the periscope examination in task 6d, where they focus on finding out if someone is observing someone using a mirror, for example, around the corner, whether the observer sees the observer in the mirror. Pupils suggest a way to find out. They implement the proposed procedure and formulate the answer to the question based on the results obtained.