Light, mirrors and images

A very familiar aspect to the children from early years is the interaction between light and materials. Children have experience with this aspect specifically about images or sparkles produced on reflecting surfaces, many times during their plays.

The shining objects used as ornamental or communicative functions and the mirrors used for seeing that is difficult or impossible to see without them are some of the oldest technologies related with light, surely as old as the use of colours.

1.2. Fields to explore

From a holistic and not sequential point of view, our didactical proposal about light, mirrors and their applications give us to consider the following fields of exploration:

- The brilliant surfaces and the mirrors.

- The images in the mirrors.

- The mirrors and the deflection of light.

1.3. Didactical considerations

The proposed activities are oriented to children from 3 to 11 years old. For these ages the didactical proposals have to connect with the experiences and with the cultural environment of children. So, our didactical proposal bases on situations that came from the social and cultural context of children. It takes in consideration aims of scientific and technological education: for example, there are moments that we are interested to understand how the light goes from one place to another, and in other moments we are interested more about what we have to do to illuminate a dark place.

The point of view that we adopt for choosing the activities is holistic and it is based on different perceptions of light and objects interactions and their consequences or social applications. So, the order of presentation of the activities not implies the same order of the childrens work. Any activity can be done when the teacher consider appropriate.

We think that the majority of proposed activities can be adapted to the children from 3 to 12 years old, but is the teacher who has to decide the specific activities that he/she can do with his/her pupils.

In the part of suggestions of procedure and questions, we emphasize the role of teacher. The teacher has to motivate the children and to support their actions and explanations. The teacher has to stimulate children to explain and to prove their ideas, but also there are moments in which the teacher has to explain. It is obvious that the language, the style and the intensity of support of teacher depend on childrens age and on the specific kind of activity.

1.4. Methodological approach

The combination of aims of scientific and technological education implies a mixture of presented methodologies commented in chapters 1 and 2 of the project.

There are activities in which the methodological approach is the analysis of objects combined with explorations of situations that can be free or oriented by questions. These kinds of activities imply to use problems solving strategies.

Other proposed activities are basically of real problems solving or based on the method of projects, where the students have to design the project and to build it.

2. The shining surfaces and the mirrors

With the activities of this field, the children develop their experience and knowledge about objects that have shining surfaces and about their applications. The pupils work with the objects that shine stimulates their capabilities of observation and explanation.

2.1. Key contents

The light reflects (shines) in a special form on objects that have polish surfaces.

Some materials (glasses, plastics, surface of water, metals, some paints) allow having especially reflective (shining) surfaces.

The shine of an object depends on its cleanness and state of conservation.

The shine of an object depends also on its lighting and from where it is looked at.

2.2. Related interdisciplinary topics

The use of shining objects as ornaments in several cultures.

The use of reflective paints in the traffic signals and in the vehicles.

2.3. Suggested procedures and questions

The teacher has to do an introduction to lead the interest of the children to the shining objects. It is advisable that in the introduction he/she uses real objects.

It is probable that some children consider that the shining objects are sources of light and so it will be necessary to do any activity to discriminate between shining objects and luminous objects.

-Which objects give us light and which ones shine?

-What do we mean when we say that something shines?

The teacher can ask to the students questions like the following, trying to concretise on objects always that were possible:

- Which objects of the class (of home, of street) shine?

- Which ones shine the most? Why they shine the most? (The biggest ones, the polished or cleaned ones, the made of glass ones, the most lighted ones, it depends from where are you looking at it...)

- If a shinning object doesnt shines actually, what do you think it is the reason? (The shining object is not clean, it is marked, rusted, or not lighted enough)

- How we can do that they shine more or less?

- For what purpose are the shining objects used? Why they have to be shining?

All these questions imply that the children must talk of their experiences with objects and have to act on objects.

2.4. Some possible extensions

Opened project of design and building of an assembly with brilliant objects. At first, the students have to look for a utility of the assembly (decorative, informative, to attract attention, etc.) and after they have to design and built it.

Investigation of which elements of security, based on the light reflection, are used in traffic.

2.5. Materials

It is possible to work with objects that are common at classroom or at home. The only special materials can be objects used in vehicles or traffic with reflective paint.

3. Mirrors and images

In this block of activities, the pupils acquire experience and knowledge about images produced by the mirrors and their applications. They develop also several skills relating space and symmetry.

3.1. Key contents

Some surfaces that we named mirrors give us defined images.

The mirrors allow us to see objects that we cannot see directly.

The mirrors that are not flat make deformed images.

The mirrors curved out (convexes) allow us to see a big space.

The images of mirrors are symmetric from objects

If we combine mirrors, we can obtain multiple images.

3.2. Related interdisciplinary topics

Using mirrors in vehicles and crossroads.

The use of mirrors to see own body (to well dress, to dance)

The entertaining use of mirrors (deformed images, kaleidoscope).

3.3. Suggested procedures and questions

It is probable that some children had problems with the words reflected image, to reflect, reflection, reflector and so it will be necessary to do some activity about meanings:

- Somebody knows what reflected image means?

- What do you mean when you say reflection?

If the brilliant objects have been worked before, the teacher could do remember to the children the work done with brilliant objects and to ask:

- In which brilliant objects can you see your image?

- In which is your image better? (Mirrors)

- Which ones do funny images? (Curved surfaces)

- In which ones can we see more things? (Convexes mirror)

- In which places and why are used the mirrors?

The teacher can propose to use the mirrors to see oneself, to see what we have behind us, to see what is hidden behind, under or over something. The students would have to practice these experiences in small groups and coached by an adult.

The teacher can introduce the didactic periscope talking, for example, of submarines. In a first stage the children have to familiarize with the use of the periscopes pieces, especially with the ones that have mirror. The children have to look at through the angular pieces and to answer questions like:

- Where is what you see?

- How have you to put this piece to see this object?

After, the teacher can do proposals about which assembly have to be made on the base of assembly of the periscope, that allow us to see an object from a specific place.

This assembly base permits the raising of several problems. The difficulty of the raised problem has to be progressive: at first with simplest assemblies and only with an angular piece and after with complex assemblies with more than one angular piece.

When the children are familiarized with the periscope and the base of the assembly, they can do activities by couples in which one of the child situate the object and the obstacles and the other have to find the solution.

The teacher can propose to experiment with two mirrors and one object for working with multiple images and ask to the children:

- How can you have two images?

- How can you have more of two images?

The teacher can bring to the classroom some kaleidoscopes (if it is possible that were dismantled) and to give them to the children. The teacher can ask.

- Does somebody know how the kaleidoscope is inside?

- Does somebody know how the kaleidoscope is made?

- Does somebody know how the kaleidoscope works?

The teacher can propose the children to dismantle the kaleidoscope and to answer the above questions.

Also the teacher can propose to experiment with two mirrors to obtain multiple images.

The teacher can propose the pupils the observation of situations in which it is seen clearly how the images are symmetric of the objects. He/she can, for example, to show the drawing of half of a face and with the mirror to obtain the whole face; he/she can show also pictures with images reflected on the water surface; with the children that can read he/she can show words written at the invert, he/she can too reconstruct an object from piece of it with mirrors, etc. The teacher can ask:

- What occurs to the face when we put the mirror?

- How is the countryside seen at the water?

- How the words and letters are seen with the mirror?

- How can we reconstruct objects with mirrors?

The teacher can propose to the children to use mirrors for completing parts of a picture or of symmetric objects or to invert images.

3.4. Some possible extensions

Opened project of design and building of an assembly with mirrors and/or pieces of periscope to see some place of the classroom or outside the classroom that were difficult to see.

Opened project of design and building of an artistic assembly with mirrors and objects or pictures.

Design and construction of a kaleidoscope.

3.5. Materials

Usual objects that do images, small plastic mirrors, some convex mirror, some mirror of dentist and big mirrors where the children can see they self complete.

Didactical Periscope: the periscope is a technological object that allows seeing objects that are not visible because they are above or rear a surface or a big object. The didactical periscope consists in an assembly of two kinds of pieces: the angular pieces that have a mirror that deflects 90º the light and the straight pieces. All the pieces can be opened to see inside them.

These pieces can be assembled on a square base that allows several plays or problematic situations more or less complexes and free depending of the age of children.

Kaleidoscopes, some of them dismountable, and plastic mirrors,

4. Mirrors and the deflection of light

The children arent aware of the propagation of light and of its role in the vision of objects and their images. With these experiences we try that the children became more conscious of the rectilinear propagation of the light and that develop their experience and knowledge about the behaviour of the incident light on the objects and specially the mirrors.

4.1. Key contents

The light travels by a rectilinear line between source and object.

When the light arrives to objects, it is reflected.

The mirrors deflect the light in a special way

4.2. Related interdisciplinary topics

The use of light to communicate messages.

4.3. Suggested procedures and questions

The teacher can propose the children to use a torch to light specific objects and he/she can ask:

- How do you have to put the torch?

- To when you have to orient the torch?

- How does the light go from the torch to the object? (The children can try to follow with the hand the way that the light makes)

- What does it happen to the light when arrives on an object or wall?

The teacher can propose the children to use a mirror to deflect the light of the torch and to orientate it to some places on the wall and ask them:

- How the light goes from the torch to the wall?

- What does it happen to the light when arrives to the mirror?

- What way makes the light from the torch to the wall?

- Why do you think you can see this object?

The teacher can propose the children to do activities with torches and mirrors orienting the light to specific points.

The teacher can propose the children to do activities with the didactical periscope. If the children dont know still the periscope, it would be necessary to do some activity of introduction to see how the light is deflected on the mirror.

If the children have worked with the periscope before now, he can do the experience uncovering it and using it to send a light beam and following the way of the light into the periscope.

The teacher can propose the children to use the periscope and the table of assemblies to send light from some place of the table to other place of the same table. He/she can propose the children to uncover the periscope and to find and draw the way that the light follows.

4.4. Some possible extensions

Opened project of design and building some communicative or lighting device or system using mirrors, or periscope and torches.

4.5. Materials

Torches, with closed beam if it is possible

Plastic mirrors.

Didactical periscope.