The Art of Teaching Primary School Science

Vaille Dawson, Grady Venville, Vaille Dawson, Grady Venville

• Editore: Routledge
• Anno: 2020
• ISBN:
  9781000248494
• Edizione: 1
• Argomento: Tecnología e ingeniería
• Categoria: Biografías de ciencia y tecnología

Children have an innate curiosity about the natural world that makes teaching science a rewarding experience.However teaching science is an art that requires a unique combination of knowledge and skills to make the most of students' interest and foster their understanding. With contributions from leading educators, The Art of Teaching Primary Science addresses the fundamental issues in teaching science in primary and early childhood years.Reflecting current research in science education, The Art of Teaching Primary Science covers the following areas: * the theoretical underpinnings of science education and curriculum;* effective science teaching practice planning, teaching strategies, investigations, resources and assessment;* key issues including scientific literacy, integrating science and technology, and activities outside the classroom.

PART I
UNDERSTANDING THE ART OF TEACHING PRIMARY SCIENCE

CHAPTER 1
THE WONDER OF SCIENCE

Allan Harrison
Central Queensland University, Queensland

OUTCOMES

By the end of this chapter you will:

• understand that science knowledge is created by people and changes as people discover new objects and processes;
• understand that scientists think about problems and develop theories that make predictions that can be tested; and
• understand that scientific theories are tested, changed and retested until every conceivable objection has been dealt with.

INTRODUCTION

One warm Queensland morning, as a teacher and I crossed a bridge over a shallow stream we saw three or four schools of tadpoles swimming in the water. The tadpoles seemed to prefer certain parts of the shallow water, and they did not respond to slow-moving shadows but darted away when a shadow quickly crossed their path. The water was flowing and clear, and little food was visible. The first questions that came to mind were: Are they cane toad or native frog tadpoles? How can we find out? As we talked about studying tadpoles and frogs in primary science, further questions arose: Why do they like to swim in some places but not others? What eats them and what do they eat? How fast do they grow? Do they sleep? What special behaviours do they show (i.e. response to light/shade, warm/cold, predators, etc.)?

As we talked, we realised that this was an excellent topic for primary science. The questions were interesting, eminently doable and open-ended. The topic is relevant because the spread of cane toads in northern Australia has major implications for native wildlife, agriculture and tourism. Studying tadpoles also is interesting because of the sharp decline in native frog numbers in Australia. Is this due to global warming, habitat destruction, pollution or new diseases? What, if anything, can we do to reverse this trend? To answer these questions requires scientific knowledge. Schools now have improved access to considerable amounts of information and students can design their own investigations, collect data and expand their knowledge of frogs, toads and habitats. A tadpole study topic has sufficient dimensions—identification, habitat study, behaviours, life cycles and population decline—to keep a class busy and such a study has the added benefit of modelling the way scientists work in groups and share and debate their findings. Individual schools could even join a state or national group that studies frog numbers and their distribution.

SCIENCE AND QUESTIONING

The tadpole study topic shows the importance of thinking and working scientifically. Questions are an excellent place to start in science. Questions draw our attention to what is already known about the subject (laws, theories, relationships and processes) and this helps in two ways: first, we don’t ‘reinvent the wheel’ and, second, we can see what previous studies have found out and what we still need to establish. Science has more questions than we could ever describe, and all sorts of scientists are trying to solve them. As we can see in the next example, problems are the lifeblood of science.

Two Perth scientists, Barry Marshall and Robin Warren, received the 2005 Nobel Prize for Physiology and Medicine (‘Australians win Nobel’, 2005) for showing that stomach ulcers were not the result of a high-stress lifestyle but were, in fact, caused by bacteria. Millions of sufferers can now be cured by a course of antibiotics instead of having to take antacids all their life and eating bland foods. (See Snapshot 1.1.)

Snapshot 1.1: A cure for ulcers and a Nobel prize

In 1979, when Barry Marshall and Robin Warren were doctors at Royal Perth Hospital, they noticed that many tissue samples taken from the stomachs of ulcer patients were infected with bacteria. One previously unknown bacterium stood out as being present in many samples. It became known as Helicobacter pylori (H. pylori). What Marshall and Warren suspected—that H. pylori was causing the ulcers—would hurt drug companies. In the United States alone, ulcer sufferers consumed over US$4 billion worth of pills and antacids. Marshall and Warren’s hypothesis was that H. pylori caused stomach ulcers and, if they were right, it could be killed with a course of antibiotics. Ulcers could be cured. This science in action story is the opening piece in Tobin and Dusheck’s college biology textbook and they use the story to show how a problem and a discovery changed the theory of stomach disease (Tobin & Dusheck, 1998, pp. 1–4).

Solving problems is not easy: Marshall and Warren had to overcome established theories that said bacteria could never live in the stomach because it is too acidic. Add to this problem their relative inexperience and lack of international reputation. Experts wouldn’t believe that the bacteria in the samples came from the stomach—perhaps the samples had been contaminated after they were removed from patients’ stomachs? For this to happen, H. pylori would have to have been present in the lab but it was previously unknown.

In 1983, Marshall presented the ‘bacteria hypothesis’ at a conference in Brussels. He was brimming with confidence but lacking convincing evidence; the idea was dismissed. Back in Perth, Marshall and Warren tried to infect rats with H. pylori and give them ulcers, but none got sick. Another setback. Was the hypothesis valid? Finally, in 1984, Marshall did what a researcher should never have to do—he brewed up a culture of H. pylori and drank it. It made him feel sick, gave him very bad breath and two weeks later his stomach was inflamed. A biopsy showed that it was swarming with H. pylori. He infected himself and then cured himself with antibiotics. It was a dangerous experiment but he’s now famous because it worked. Good science, imagination, tenacity, good luck or just hard work? Probably a mix of all these things.

When this evidence was added to the curing of H. pylori infections with antibiotics, doctors and scientists started to listen to Marshall and Warren. As with every major advance in science, it took time for people to accept Marshall and Warren’s hypothesis because scientists are sceptical and they test and retest every new idea. When old theories are challenged and objections answered, stronger theories emerge.

For more information, see http://nobelprize.org/medicine/laureates/2005/index.html and http://www.hpylori.com.au.

Plate tectonics and continental drift are theories that once were ridiculed but now are accepted as if they were never questioned. Scientific theories can develop in piecemeal fashion and some progress slowly, others very quickly. Alfred Wegener is often credited with the theory of continental drift; but at least ten scientists were involved in the development of plate tectonics and to whom does the credit belong? Examine the evidence in Snapshot 1.2 and decide who invented plate tectonics. (See http://kids.earth.nasa.gov/archive/pangaea/evidence.html and http://whyfiles.org/094quake/index.php?g=6.txt for useful additional information.) As you read the story, notice how scientists questioned and refined these theories and see how important the growth in technology was in answering key questions. Sometimes great ideas founder because they are too far ahead of their time and the technology necessary to provide the essential corroborating evidence.

Snapshot 1.2: Who invented plate tectonics?

Back in the 1600s, English scientist and philosopher Francis Bacon noticed that the coastlines of South America and Africa fit together like a jigsaw puzzle. Two hundred years later, German scholar and explorer Alexander von Humboldt made the same observation. The first person to propose that the continents had once been joined and had moved apart was a French geographer, Antonio Snider-Pellegrini, in 1859. In 1885, Austrian geologist Eduard Suess argued that similar fossils on adjacent continents meant they once were connected. He believed that the continents moved as the molten Earth cooled and mountains formed like the wrinkles that develop on a shrivelling apple. Suess felt that southern Africa, Madagascar and India were once one continent he called Gondwana. Using his ‘drying apple’ model, Suess proposed that compression caused the landmass between present-day continents to move vertically downwards to form the ocean floor. In 1910, American geologist Frank Taylor stated his ‘continental drift’ hypothesis—he argued that moving continents pushed up mountain ranges. Most geologists, however, rejected continental drift.

In Germany, Alfred Wegener published The Origin of Continents and Oceans in 1915. He claimed that geological, biological and meteorological evidence combine to indicate that today’s continents are fragments of an original super-continent called Pangaea. Knowing that continental and oceanic crust are radically different in density and thickness, Wegener rejected Suess’s view that continental crust could be converted to oceanic crust by vertical collapse. Wegener was convinced that continental crusts had moved apart.

Geologists and geophysicists disbelieved Wegener’s hypothesis because contemporary technology could not supply the necessary evidence. One problem was that ordinary volcanic activity could not account for the conduction to the surface of all the heat generated by radioactive decay in the mantle. In the 1930s, English geologist Arthur Holmes, who investigated many possible mechanisms, suggested that convection currents in a movin...