Introduction

Introductory remarks on astronomy education in Croatia are given. Since the learning process is a complex intellectual and emotional process which should be supported during the interaction with the teacher, different approaches should be used. Tests could give useful insight into preconceptions. The following approaches should be balanced: historical approach, discovery approach (by the use of self-made tools and courtyard observations), and thorough inclusion of novel scientific results and views (to which a special precaution has been paid).

The Croatian Experience

This is a report about an experience in teaching astronomy to the students who will become teachers in physics or physics and mathematics. It should be stressed that astronomy in Croatia is not a standard subject in any schools, except as an elective course in some grammar and high schools; furthermore, astronomical concepts are partly exposed within physics.

The first step toward students should be mutual acquaintance. In order to test students’ previous knowledge, I used 20–25 questions mainly of a general nature (starting in 1975). I had the opportunity to teach at all four Croatian universities: Zagreb, Osijek, Rijeka and Split. People in these towns may have different backgrounds. Zagreb is the capital of Croatia and cosmopolitan. Osijek is the center of Slavonia and belongs to an agricultural and Panonian environment. Split is heart of Dalmatia and situated on the Adriatic Sea – in the Mediterranean region. Without regard to differences in life attitudes, temperament and historical background of populations, the test showed a low level of general knowledge in natural sciencies, especially regarding comprehension of objects and scientific terms.

We are all aware of the fact that Astronomy teaching is not an easy task for many different reasons which we are going to examine during this Colloquium. The present contribution focuses on one of these reasons we consider of major importance for Astronomy in the school: Teacher Training.

Teacher training has been debated extensively for a long time and discussion is being presently livened up.

Institutions and associations are promoting research, studies and comparisons on this issue. For instance, the Osnabriick conference “Teacher Education in Europe: Evaluation and Perspectives” (June 1995) – the International Forum of Rome (September 1995) and, specially devoted to Astronomy, the EU/ESO Workshop “Astronomy teaching in the European secondary school” (Garching, 1994), SAIt Workshop in Reggio Calabria “European Science Teacher Training” (September 1995), Conferences of Teaching Astronomy in Spain, the Constitutional Conference of the European Association for Astronomy Education (EAAE, Athens, 1995).

It is difficult to treat Astronomy teacher training without including it in a more general context. Teacher training does not only mean providing teachers with suitable teaching skills for each subject. First of all, teachers should bear in mind the interaction with a social and cultural reality that may affect learning processes. And the educational (and teaching) system is not neutral to the external framework. European and non-European countries have their own national differences with different school systems and choices made in the field of teacher training. Time does not allow us to go in detail into a comparison of the various solutions adopted in different countries.

Sundials in my life

Following the inclusion of Astronomy in the revised National Science Curriculum for England and Wales the Association for Astronomy Education, AAE, embarked on a programme of in-service training workshops for teachers to help them to understand the new ideas and deliver the new curriculum. Teacher confidence and knowledge has been the greatest challenge to establishing astronomy in school curricula. As part of the the AAE team I gave presentations on a host of activities including simple cut and paste sundials for pupil projects. We are now seven years on from the revised Science Curriculum and my interest in sundials has stepped up a gear. I have developed an interest in real dials, both studying existing dials and making dials for the homes of friends and families and for schools. This presentation, which has as its focus, the sundial as an architectural feature, uses slides I have taken of some of the dials to be seen in the central London area including some of my own. I am grateful to the British Sundial Society for a list of dial locations in London.

Understanding the hour lines – a model helps

To help explain how hour lines are related to the Suns motion I have developed a three dimensional stick and card model. The model, in four pieces, builds up gradually during a workshop presentation. I start with an equatorial dial showing 15 degree angles marked on an equatorial plane. (360 degrees / 24 hours – the only maths you really need to understand dials.)

Introduction

A summary of work related to astronomy education carried out during the last three years in India is presented here. Since India is a huge country and many educational efforts are made by individuals alone, this report cannot be regarded as complete, but a specific sampling.

General Information

India has more than 200 Universities, 8000 colleges, and about 100,000 schools, 33 planetaria, more than 100 museums and about 60 well known amateur astronomers' clubs. Scores of dedicated astronomy oriented school teachers, act as nuclei of astronomy education for the general public and school children.The astronomical almanac, used in a typical household is in some way related to the stars in the sky and the movements of the Sun, the Moon and the planets. Traditionally, a rudimentary knowledge of the celestial sphere is common. The recent developments in space technology have brought a fascination and glamour to modern astronomy for all age groups, and this is noticeably reflected in the number of media coverages of astronomy. There are about 12,000 telescopes of aperture no less than six inches, made by amateur astronomers.

Public Awareness

During the past three years there have been at least 300 six inch telescopes made by school children and laymen, under some project or other funded by the government and an equivalent number is also produced from private and individual resources. It takes about two weeks to grind and polish the mirror and assemble it in a suitable mount. After aluminizing the average cost comes out to be in the range US dollars 60–100, for a telescope of size greater than six inches.

Introduction

Having recently returned to England (where I am an Open University tutor) after having spent about 18 years teaching Physics and Astronomy at the University of Nigeria at Nsukka in the Eastern part of Nigeria, I find myself in an unusual position to understand the difficulties of teaching such a rapidly changing subject as astronomy in an isolated place like Nsukka. For example I have seen a great contrast between the OU Astronomy and Planetary Science course material and the few available text books at Nsukka. Although not very mathematical, the OU material includes a lot of the latest research results and theories, whereas at Nsukka the books have hardly changed in the past 20 years.

I am aware that the Astronomy group at Nsukka is not unique. There are other small isolated groups of astronomers (or in some cases only a single astronomer) around the world who are trying to interest their students in astronomy against great odds. These astronomers appreciate the importance of astronomy in awakening interest in science and thus strengthening the basic sciences and developing technological progress. However Governments and even some international agencies often take the view that astronomy is a luxury that is not needed by such developing countries and therefore give little or no support to these efforts.

Main Problems

Apart from the lack of teaching materials, extremely limited access to computers and generally poor infrastructure, the one major problem is the extremely poor communications. Often phone, fax and mail do not work reliably, and needless to say there is no e-mail or internet.

INTRODUCTION

A distance teaching course in Astronomy was developed three years ago by the CNED (Centre National d'Enseignement Distance) in collaboration with professional astronomers from the University of Paris Sud XI.

We wish to present our course with:

• the conceivers and designers’ point of view

• the learners’ point of view.

Creation of the course.

Centre National d'Enseignement a Distance (CNED).

The CNED was created in 1939. It is a public administration under the supervision of the French Ministry of Education. Its first founding mission is to provide teaching and training to those who cannot take courses under usual conditions. But the CNED now operates at all the levels of the educational system from primary up to higher education, in all fields of training, initial, vocational and continuing education.

In 1995-1996, 360 000 students were registered in 2 500 training modules. Among them, 80% are adults, 190 000 on post baccalaureat level programmes (27 000 registered students reside outside France, in 176 countries).

A partnership between CNED and Paris XI University.

As no such course existed for astronomy, its creation was timely. So, as we did for meteorology in 1990, the CNED which does not deliver diplomas, offered and set up a partnership through an agreement with the University of Paris XI.

We worked with a team of Professors from that university, professional astronomers who are also well-known for working in collaboration with primary and secondary school teachers (CLEA).Together we decided, conceived and designed a remote teaching course with a multi-resource system.

INTRODUCTION

A typical science course at the high school level includes some information on planets and their moons. For example, it is well-known that Jupiter has 16 moons and Saturn has 18 moons. Add to this the enthusiasm of the public in the collision of comet Shoemaker-Levy 9 with Jupiter in July 1994. This immediately raises the possibility of a collision of a comet with a moon of Jupiter. Due to this possibility a strange fact about these moons comes into the picture, that is some of them are prograde in nature and some are retrograde. Can these two types of moons pose any problems in teaching? The present situation in education leads us to believe that they can pose some problems. It is described below, in support of this answer.

Educators from many countries have observed that the Aristotelian ideas continue to persist among graduates, in spite of learning Newtonian mechanics in colleges also. This is evident, for example, in the fact that many students think that a tangential force acts on a body performing circular motion, instead of the centripetal force. So the greatest and global problem is how to get rid of the tangential force from the minds of students and how to impregnate the centripetal force instead.

Recent history of science education reform in the USA

In 1981, in response to growing concerns that the United States was falling behind the rest of the world educationally, the federal Secretary of Education created a national commission on excellence in education. This commission was charged with gathering data about the status of U.S. education compared to the rest of the developed world and to define the problems which would have to be faced to successfully pursue the course of excellence in education.

In 1983 this commission issued its report, A Nation at Risk, (Secretary of Education, 1983). The release of this book produced a flurry of activity by schools, political entities and professional groups representing various educational disciplines. These groups included, the National Council of Teachers of Mathematics, the National Governors Association and the National Science Teachers Association and others. By 1989, the American Association for the Advancement of Science (AAAS), a major American organization representing a broad spectrum of the sciences, produced its own call for an improved educational climate for science and engineering. Their book, Science for All Americans, attempted to produce a comprehensive expression of the scientific community as to what constitutes literacy in science, mathematics and technology (Rutherford and Ahlgren, 1990). The release of this report, coming from a credible, broad-based and nationally recognized organization of scientists and engineers produced a great deal of interest in the American press and calls came for developing strategies for action.

The Edinburgh Teaching Packages.

For many years, copies on film of photographs, both direct and through objective prisms, taken with the 1.2 m United Kingdom Schmidt Telescope, have provided teaching material suitable for universities and colleges (Brück and Tritton, 1988). Table 1 outlines the various types of application to which the photographs may be put. With additional data, some real physics can be injected into the exercises, allowing students to perform quite elaborate projects.

Uses for UK Schmidt Telescope Film Copies

Direct photographs

1. 1. Recognition of objects:

2. galaxies

3. minor planets

4. HII regions, SNRs (in external galaxies)

5. globular clusters (in the Magellanic Clouds)

6. 2. Statistics

7. star-counts, for various purposes

8. number-magnitude counts

9. star-galaxy counts

10. galaxies in clusters

11. 3. Changes in position (from more than one photograph)

12. precession

13. comet

Objective prism photographs

1. 1. Spectral classification:

2. coarse classification (of about 100 stars per film)

3. 2. Search for unusual objects:

4. emission-line stars

5. carbon stars

6. planetary nebulae

7. quasars

A limitation to such purely visual observations is in regard to photometry, where we have to make do with rather rough estimates of magnitude. Measuring the brightnesses or magnitudes of objects is a basic necessity in astronomy, but one that is, ironically, less easy to perform with students than it was ten or twenty years ago. Instruments that were once standard equipment and could be employed on the films – photographic photometers and microphotometers – have fallen into disuse as astronomers receive their data ready processed. For the brighter stars, down to magnitude 13 or 14, magnitudes may be estimated visually to about a fifth a magnitude. This is adequate, however, for our stellar statistics problems (e.g. Fig. 1).

The Dilemma of the Introductory Astronomy Laboratory

Were we meeting a century ago to discuss the state of astronomy education, we might have noted that remarkable changes were taking place in our field. The discipline, then regarded as a branch of geometry or mechanics, concerned itself primarily with the determination of positions in the heavens and the mapping of places on the earth. But with the advent of spectroscopy and the construction of large telescopes, astronomy was beginning to probe the how and the why of the heavens as well as the where and when. It was, in short, transforming itself into astrophysics, the study of the physical nature of the universe.

A century ago, we would have called for a change in the things we teach; and in fact there was such a change. When we look at the astronomy of the succeeding century, the material we now offer to introductory astronomy students at most universities and colleges, we see only a vestige of the earlier preoccupation with place and time. Judging by most textbooks, and by the course syllabi I have seen, most of us devote only a small fraction of our courses to astronomical coordinate systems, timekeeping, geodesy, and celestial mechanics. When we teach the solar system, we teach comparative planetology. When we teach the stars, we teach about main sequence and giant branch, about hydrostatic equilibrium and neutron degeneracy, about pulsars and supernovae. When we discuss the universe at large, we teach about the physics of the early universe, the dynamics of galaxies, and the fundamentals of general relativistic cosmology.

This lecture series provides an overview of modern physical cosmology with an emphasis on nuclear arguments and their role in the larger framework. In particular, the current situation on the age of the universe and the Hubble constant are reviewed and shown now to be in reasonable agreement once realistic systematic uncertainties are included in the estimates. Big bang nucleosynthesis is mentioned as one of the pillars of the big bang along with the microwave background radiation. It is shown that the big bang nucleosynthesis constraints on the cosmological baryon density, when compared with dynamical and gravitational lensing arguments, demonstrate that the bulk of the baryons are dark and also that the bulk of the matter in the universe is non–baryonic. The recent extragalactic deuterium observations as well as the other light element abundances are examined in detail. Comparison of nucleosynthesis baryonic density arguments with other baryon density arguments is made.

Introduction

Modern physical cosmology has entered a “golden period” where a multitude of observations and experiments are guiding and constraining the theory in a heretofore unimagined manner. Many of these constraints involve nuclear physics arguments, so the interface with nuclear astrophysics is extemely active. This review opens with a discussion of the three pillar of the big bang: the Hubble expansion, the cosmic microwave background, and big bang nucleosynthesis (BBN).

This review concentrates on nucleosynthesis processes in general and their applications to massive stars and supernovae. A brief initial introduction is given to the physics in astrophysical plasmas which governs composition changes. We present the basic equations for thermonuclear reaction rates and nuclear reaction networks. The required nuclear physics input for reaction rates is discussed, i.e. cross sections for nuclear reactions, photodisintegrations, electron and positron captures, neutrino captures, inelastic neutrino scattering, and beta–decay half–lives. We examine especially the present state of uncertainties in predicting thermonuclear reaction rates, while the status of experiments is discussed by others in this volume (see M. Wiescher). It follows a brief review of hydrostatic burning stages in stellar evolution before discussing the fate of massive stars, i.e. the nucleosynthesis in type II supernova explosions (SNe II). Except for SNe la, which are explained by exploding white dwarfs in binary stellar systems (which will not be discussed here), all other supernova types seem to be linked to the gravitational collapse of massive stars (M>8M⊙) at the end of their hydrostatic evolution. SN1987A, the first type II supernova for which the progenitor star was known, is used as an example for nucleosynthesis calculations. Finally, we discuss the production of heavy elements in the r–process up to Th and U and its possible connection to supernovae.

This chapter is a review of the background and status of several current problems of interest concerning cosmic rays of very high energy and related signals of photons and neutrinos.

Introduction

The steeply falling spectrum of cosmic rays extends over many orders of magnitude with only three notable features:

1. (a) The flattened portion below 10 GeV that varies in inverse correlation with solar activity,

2. (b) The “knee” of the spectrum between 1015 and 1016 eV, and

3. (c) the “ankle” around 1019 eV.

4. For my discussion here I will divide the spectrum into three energy regions that are related to the two high–energy features, the knee and the ankle: I: E < 1014 eV, II: 1014 < E < 1018 eV and III: > 1018 eV.

In Region I (VHE) there are detailed measurements of primary cosmic rays made from detectors carried in balloons and on spacecraft. These observations, and related theoretical work on space plasma physics, form the basis of what might be called the standard model of origin of cosmic rays. Cosmic rays are accelerated by the first order Fermi mechanism at strong shocks driven by supernova remnants (SNR) in the disk of the galaxy. The ionized, accelerated nuclei then diffuse in the turbulent, magnetized plasma of the interstellar medium, eventually escaping into intergalactic space at a rate that depends on their energy.

The structure of neutron stars is discussed with a view to explore (1) the extent to which stringent constraints may be placed on the equation of state of dense matter by a comparison of calculations with the available data on some basic neutron star properties; and (2) some astrophysical consequences of the possible presence of strangeness, in the form of baryons, notably the Λ and Σ−, or as a Bose condensate, such as a K− condensate, or in the form of strange quarks.

Introduction

Almost every physical aspect of a neutron star tends to the extreme when compared to similar traits of other commonly observed objects in the universe. Stable matter containing A ∼ 1057 baryons and with a mass in the range of (1 − 2) M⊙ {M⊙ ≅ 2 × 1033 g) confined to a sphere of radius R ∼ 10 km (recall that R⊙ = 6.96 × 105 km) represents one of the densest forms of matter in the observable universe. Depending on the equation of state (EOS) of matter at the core of a neutron star, the central density could reach as high as (5 − 10)p0, where p0 ≅ 2.65 × 1014 g cm−3 (corresponding to a number density of n0 ≅ 0.16 fm−3) is the central mass density of heavy laboratory nuclei (compare this to P⊙= 1.4 g cm−3).

This paper presents a discussion of the characteristic observables of stellar explosions and compares the observed signatures such as light curve and abundance distribution with the respective values predicted in nucleosynthesis model calculations. Both the predicted energy generation as well as the abundance distribution in the ejecta depends critically on the precise knowledge of the reaction rates and decay processes involved in the nucleosynthesis reaction sequences. The important reactions and their influence on the production of the observed abundances will be discussed. The nucleosynthesis scenarios presented here are all based on explosive events at high temperature and density conditions. Many of the nuclear reactions involve unstable isotopes and are not well understood yet. To reduce the experimental uncertainties several radioactive beam experiments will be discussed which will help to come to a better understanding of the correlated nucleosynthesis.

Introduction

Historically, the field of nuclear astrophysics has been concerned with the interpretation of the observed elemental and isotopic abundance distribution (Anders & Grevesse 1989) and with the formulation and description of the originating nucleosynthesis processes (Burbidge et al. 1957; Wagoner 1973; Fowler 1984). Each of these nucleosynthesis processes can be characterized by a specific signature in luminosity and/or in the resulting abundance distribution.