ARCturus

The development of the world view is a natural result from the growing and aging of man, who constantly observes his surroundings. It starts from the nearest neighbourhood and widens to larger and larger entities. Only a very small part of the huge universe can be observed with the naked eye. In the picture there are two constructional units of the universe based on the students’ ideas (picture IH, Finland).

 

Aim: Get acquainted with the construction of the universe and its formation.

 

Explorations: Discuss with the students and find out how they perceive the surrounding universe. Let them freely bring out their perceptions, do not classify or evaluate them. It is worthwhile to draw a concept map on the wall.

 

Furthermore, ponder the restrictions of the human eye in recognizing electromagnetic waves and being able to observe various objects. The eye can only see a very narrow part of the electromagnetic spectrum, i.e. the light waves. A major part of the waves in a spectrum is invisible to the eyes. That is why the information received in these wavelength ranges from the universe must be observed in some other way.  

 

The results from the scientific research show that the universe consists of large structural entities which, in turn, consist of smaller units. This construction seems to prevail even in the micro world which is invisible to the human eye. One unit is a part of another little bigger unit. Finally, all structural units, from the tiniest of the micro world to the largest macro world, form a chain of units in which each unit contains the smaller units and is larger than the previous one.  

1) Explore with the students the surroundings outdoors. Ask students to tell what they see. First, observe objects on the Earth’s surface. When the students suggest objects in the sky, such as the Sun and the Moon, it is time to ponder together the relation between them and the Earth in the universe. If it is twilight or dark in the evening, it is natural to start discussing the stars and their position in the visible space. In the classroom, the students can draw pictures of their observations. Discuss how illustrative the pictures are and correct the misunderstandings if there are any.

 

2)  Continue the observation when it is dark. Try to locate planets. It is worthwhile to use a current star map to ensure what planets can be seen and in what constellation they can be found. Ask the students to use a star map to find planets. Discuss the visibility and the position of the planet in relation to the stars. If there are no planets to be seen, the class can, in theory, explore their motions and positions in relation to the Sun and stars.

 

3)  Before the next observation, recall the structural units of the universe which are already familiar to the students, i.e. the Earth and Moon, Solar System and stars. The object for exploration will be the next bigger structural unit, the galaxies. In the northern hemisphere the nearest galaxy is Andromeda. It can be seen even with good binoculars. An experienced stargazer can see it even with the naked eye, provided that the night is clear and the amount of light pollution is close to zero. As a matter of fact, because of the constitution of an eye, the best way to see the faint light spot is to look a little beside the object. With the help of a telescope it is possible to see many galaxies. A star map or a planisphere helps in finding them. The students write down the observations of the classmates. There still may be a need to discuss in the classroom the distances between galaxies.

 

4)  Gather the results to a constructional chart on the classroom wall. Position the Earth in the middle of the chart. Since the chart is two-dimensional, it is only curves that can be used to indicate the three-dimensional structural units which are inside each other in an enlarging or diminishing chain. Choose the directions starting from the Earth to the micro and macro world. When proceeding from the Earth to the macro world, the structural units are the Solar System, galaxies, groups of galaxies and the giant group, all the way to the utmost boarder of the known universe.

 

5) * Discuss with the students objects smaller than the Earth. Ponder together the discerning ability of the eye in the micro world. Add small objects to the structural map. For illustrative reasons it may be good to include some extra topics appropriate in the map, such as man and a cell. When proceeding from the Earth to the micro world, the structural units are man, cell, molecule, atom, and nucleus. Quarks can also be mentioned in this connection.

 

6) * Discuss, with the finished structural model at hand, the structure of the universe and distribution of matter. Use imagination to survey the space from outside. What is there between the structural units, or between the parts in the structural unit? Explore the chart of cosmic background radiation based on the latest researches. Matter seems to have spread in quite an even way, though there are some uneven regions, though. They appear to be either hot or cold.

 

 

7) * Exploring the dark sky and stars enhances the understanding of the structure of the universe. Find information on the newest astronomical subjects of research, such as the distribution of the galaxies and their velocity of rushing away from each other, i.e. the receding velocity, as well as the cosmic background radiation.

 

Methods: Observation in nature, using star maps, preparing a structural chart, evaluation of the most recent research results.

 

Materials: Telescope, binoculars, star map.

 

Pondering: With the help of a distance line, it is possible to realize how narrow the region of the universe is that the human eye can see. Compare this ratio with the part that the visible light has in the electromagnetic spectrum.

 

Evaluation of the results: With the finished structural chart at hand, discuss all relevant topics in mind. Let the students bring out both positive and negative issues. Ponder together how to improve the chart to be more illustrative.

 

Hints: If there were enough space available, it would be worthwhile to consider preparing the model in a correct scale. Is it possible or not?

 

Keywords: Universe, structural unit, macrocosm, microcosm, cosmic background radiation, receding velocity, distribution of galaxies, 3 degree background radiation, thermal radiation, Hubble Space Telescope.

 

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