ARCturus

The Solar System is the biggest unit in the space the motions of which man can observe. Changes in the motions can be seen daily or during a short time lapse. Some objects need to be observed for a long time in order to see their motion. The Solar System as a whole is an interesting entity. It is easy to build a scale model with the students of. The picture shows a preparation of a model of the Solar System in a park. A sheet illustrating the Sun is being fixed on the fence of the school in Briey, France (picture IH, Finland).

 

Aim: To prepare the Solar System in a chosen scale and space.

Explorations: First, recall the basic information on the planets: their sizes and distance to the Sun. Discuss the option to implement the model. There are at least two major topics to be pondered: What parts of the Solar System are worth including in the model? What are the parts that are not fitting in a scale model?

1) First choose a suitable space for the model. It can be a classroom, a corridor outside the classroom or an open space in the schoolyard. What space will be chosen depends on many things, such as plans for the rate of utilization, materials used and vulnerability.

In order to maximize the utilization rate, it is best to prepare the model near the classroom where it is easily available. The model in the classroom can be used in teaching at any time. It interests the students and the mere presence of it helps them to recall what was taught earlier. On the other hand, the model in the corridor or outdoors can simultaneously be used by many groups. However, since the model is not constantly at hand, using it needs more planning.

The space for the model sets conditions for the materials to be used. If the model is prepared outdoors, the materials should resist humidity, cold and even heat. Also the impact resistance to some extent is advisable. Light and more fragile materials can be used in the models indoors.

The vulnerability, in this connection, means that the model should have resistance against damages or deliberate destruction. It is rather difficult to protect the model from damages outdoors. That is the case if the educational guidance has failed to support the good behaviour of the students.

2)  In a chosen space, mark the positions of the various parts of the Solar System in a correct scale. The students can find the positions by following the mathematical instructions they have been given. First, determine the longest distance available in the space. In the scale, it means the distance between the Sun and the farthest planet, Neptune. The positions of the other planets are determined by using some simple inferential method or mathematically, e.g., using proportion. The size of the Sun is a challenge when preparing the model indoors. The problem can be solved by suggesting to the students that the Sun, in fact, is not prepared at all but only is indicated by a two-dimensional picture on the wall or a place in the corner of the classroom.  It needs to be emphasized though, that this arrangement does not create a correct impression of how immense the Sun actually is. That is because the distances and sizes are not in the same scale.

However, in the model prepared outdoors, the scale for the distance and size can be the same. In the picture above, the diametre of the Sun on the sheet is in the same scale as the distances between the Sun and the other parts of the model. Also the diametres of the planets are prepared in the same scale. In this model, too, the implementation of the spherical Sun has been quite challenging.

3)  The next thing to do is to determine the diametres of the planets in the chosen scale. Make teams of the students and provide each team with a task to prepare a model of one part in the solar system.

The biggest planets can be prepared by squeezing paper into the sizes determined. The squeezed balls can be covered with paper and painted with colours appropriate for each planet. In literature and on the Internet, a lot of information can be found on the colours typical for the planet. The consistency of the surface on the planet causes the various colours.

Small balls, pearls or marbles may indicate smaller planets. Also, they can be painted either as such or by painting the cover paper if used.

If the students find this task inspiring and it interests them, they can improve the model further and add some special parts in it, such as the rings of Saturn, the moons of the planets, as well as asteroids or comets. It is most important to encourage the students to use their imagination and creativity. They often are very innovative and have myriad ideas.

4)  When the parts are completed, it is time to combine the model. In the beginning, it already was decided where the model would be erected and what kinds of fixing materials would be used. Each team can fix their own work in a position marked. If the model is meant to be indoors hanging from the ceiling or high on the wall, the job of hanging it, for safety reasons, belongs to the adults.

5)  Before introducing the model, it is worthwhile that the teams make a short introductory text of their work. By using conspicuous fonts, the text can inform the reader on the most important features, such as the right size, distance from the Sun, constitution of surface, revolution time, rotation time and amount of satellites if there are any. The papers, easy to read and introductory, can permanently be fixed in the model for the benefit of the visitors. Each part of the Solar System is introduced orally and the phases of the preparing work are discussed in detail. Also the possible deficiencies are worth discussing. Pondering options for improving the model is useful. In the picture, there is one implementation of the planets, designed by the students. The planets are made in a scale according to size. Their material is paper mass and they have been coloured as real as possible. The planets have been fixed in the ceiling of a cardboard box. The piece of paper fixed in the yarn contains the basic information on the characteristics of the planet. The wall on the background is full of holes with Christmas light lamps in them to indicate stars in the far universe (picture IH, Finland).

 

 

6) * The model outdoors is also suitable for making an illustrative solar eclipse test. Replace planet Earth with a plate which has a hole with the diametre of the Earth. Position the Moon fixed in a wire on the line between the Sun and the Earth. The diametre and distance of the Moon from the Earth are in a scale. Observe the Sun through the ‘Earth’-hole. If the scale is correct, the Sun should be totally covered by the Moon. Discuss the solar eclipse and ponder what the annular eclipse would mean in this model.

7)  * The students can make either a Power-point presentation or a video presentation of the model. It can be shown during the lessons at school, or it can be on the agenda of an event or happening so it reaches a wider audience: other students and personnel at school, parents and other guests in the happening. The home pages of the school widen the audience of the presentation even more.

Methods: Adjusting many parts of various sizes in a chosen space with the help of mathematical methods. The size and distance can either be presented in the same scale or both can have their own scale. Preparing the parts in teams. Writing the introductory texts. Presenting the model either orally or by using pictures.

 

Materials: A large piece of cloth, balls, paper mass, colours, craft materials, calculators, fixing material.

 

Pondering: With the students, it is worthwhile to carefully consider the position and vulnerability of the model. It is important that the students express a clear commitment to preparing, introducing and protecting the model. Also when choosing the scale, it is good to listen, hear and keep in mind the students’ visions and ideas. However, the emphasis needs to be put on both pluses and minuses of both options.

 

Evaluation of results: With the completed model at hand, there is a need for many sessions with the students. Find together good and bad sides and ponder whether the model can later on be improved or developed to be more detailed. How to demonstrate the Sun? This question needs a lot of discussion, particularly if the Sun is shown as a big two-dimensional circle. It is very important that the students get a correct impression of the real essence of the Sun.

 

Hints: The model also helps to illustrate the solar eclipse to the younger students. The older students can be encouraged to draw a diagram of the case on paper. How is the lunar eclipse formed? This is an interesting topic that can also be discussed and illustrated with the help of the model.

 

Keywords: Solar system, planet, planet system, astronomical unit, solar eclipse, lunar eclipse.

 

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