LeSa21: primary-school science activities
Submitted by celius on 24 September 2010
Launched in 2002 by Astrid Kaiser from the University of Oldenburg, Germany, the LeSa21 websitew1 offers a range of experiments, resources and background information for primary-school science and humanities lessons. Materials for both teachers and their pupils are available on a wide range of topics (currently 93), including ‘The eye’, ‘bicycles’, ‘spring’, ‘health and disease’, ‘girls and boys’, ‘planets, the Moon and the stars’, ‘electricity’, ‘water’ and many others. These materials are developed mainly by university students who are training to be primary-school teachers.
Available in English, German and Spanish, the ‘Learning’ section is suitable for both children and teachers, and includes experiments, stories, poems, pictures, book recommendations and links to relevant websites for each of the topics.
Below are some activities from the LeSa21 project, which could form the basis of a teaching unit on oil and water, including surface tension and the removal of oil spills, suitable for older primary-school children. The individual experiments and further materials on the topics can be found on the LeSa21 websitew1.
Soap has magic powers – surface tension
This experiment introduces the notion of surface tension.
Initially, both the pepper and pin float. One reason is that they are both very light; the other is that water has a kind of thin, invisible ‘skin’ on its surface. Light things do not break this skin, but are supported by it – some animals, e.g. water striders, can even walk on it (see image above). This thin skin is caused by surface tension.
When you added the soap drop, the pepper probably moved away from it and slowly sank. The pin would have sunk immediately.
Why is that? The soap breaks this thin skin of the water – you could also say that soap reduces the surface tension. As the skin disappears, there is nothing left to hold the pepper and the pin on the surface of the water, so they sink. Although this is how it may look, pepper and soap do not repel each other – the tension of the rest of the water (where the soap has not yet reached) pulls the floating pepper away from the soap.
Soap has magic powers – mixing oil and water
The oil spill
In April 2010, an explosion on the oil rig Deepwater Horizon in the Gulf of Mexico led to a catastrophic oil spill. As we go to press, an estimated 5000-100 000 standard barrels of oil per day have been leaking out for several months, the spill eventually reaching the southern coasts of the USA. Attempts to remove the oil included burning it and using chemical and mechanical binding agents.
Compare and discuss the results of the experiments. The children should realise that the best results are achieved with a combination of (mechanical and chemical) methods. They may also consider the factors affecting the efficiency of each method, e.g. the volume of removal agent used. Finally, they should notice that there will always be some oil left in the water at the end; in real-life situations, we have to rely on the ecosystem to deal with this remainder over time.
Which other methods of cleaning the water can you imagine? Let the children come up with some ideas for real-life ‘oil spill removal machines’. Ideas might include a ring of cat litter to stop the oil from floating away, plus mechanical diggers to remove the floating oil film.
The origins of Lesa21: boxes of experiments
The origins of Lesa21 go back to the RÖSA projectw2, which is still continuing at the University of Oldenburg. Since 1994, images, stories, experiments and background information for primary-school science and humanities lessons (Sachunterricht) have been sorted by topics and collected in boxes that local teachers can borrow.
The experimental equipment in the boxes is mostly recycled material found in standard households or industry, such as broken mirrors, pipettes from empty medicine bottles, boxes of old buttons, stones and used guitar strings. The objects not only provide an inexpensive source of experimental equipment, but also demonstrate to the children that materials can be used over and over again in different and creative ways. Individual boxes have been created on 70 different themes, many of them the same as the current LeSa21 topics. The ideas and materials are tested in local schools by university students and trainee teachers.
Several satellite Lernwerkstätten offer similar collections of boxes, mainly in schools across northern Germany, but also at the Pädagogisches Beratungszentrumw3 (education centre) in Brixen, northern Italy. In addition, a book has been published for Japanese teachers, who are now also working with the box system (Kaiser et al., 1999).
The two experiments ‘Soap has magic powers’ are part of the book Chemie in der Grundschule (Chemistry in Primary School; Kaiser & Mannel, 2004). Published in German, it contains many other experiments on different topics.
Parts of ‘The oil spill’ experiment are from Kaiser (2009).
w1 – For more information about LeSa21, see: www.lesa21.de
w2 – To learn more about the RÖSA project, see: www.roesa.uni-oldenburg.de
w3 – Find out more about the Pädagogisches Beratungszentrum in Brixen, Italy, here: www.schule.suedtirol.it/pbz/brixen
The Australian Maritime Safety Authority has developed a series of very good educational resources for primary- and secondary-school children about oil spills, including several games, animations and the mathematics of oil spills. See the website (www.amsa.gov.au) or use the direct link: http://tinyurl.com/375ny3e
You might also want to browse the ‘Bridge’ collection of free marine education resources from the Virginia Institute of Marine Science, USA, searching for ‘oil spill’: www2.vims.edu/bridge
The US National Wildlife Federation offers a special section on the 2010 oil spill in the Gulf of Mexico, including background information and teaching activities. See the website (www.nwf.org; search for ‘oil spill school’) or use the direct link: http://tinyurl.com/36sqg45
The US National Oceanic and Atmospheric Administration has developed a comprehensive teaching module on how an ecosystem recovers from a major oil spill, based on the Exxon Valdez disaster 1989 in Alaska’s Prince William Sound (‘Prince William’s oily mess’). See the website (http://oceanservice.noaa.gov) or use the direct link: http://tinyurl.com/ofvaxk
The US education organisation The League offers a four-lesson plan on oil, water and wildlife: http://learningtogive.org/lessons/unit377
For a broader consideration of hydrocarbon fuels, see:
van Dijk M (2009) Hydrocarbons: a fossil but not (yet) extinct. Science in School 12: 62-69. www.scienceinschool.org/2009/issue12/energy
If you enjoyed reading this article, you might want to browse the other Science in School articles for primary-school teachers: www.scienceinschool.org/primary
Both RÖSA and LeSa21 were initiated by Professor Astrid Kaiser at the Carl von Ossietzky University of Oldenburg, Germany, where she is the director of the Institute of Education Science and teaches didactics for primary-school science and humanities lessons (Sachunterricht). Her main focus is on gender issues, science, ecology and energy education in primary school and kindergarten. She has published numerous research papers and more than 40 books.
Dr Marlene Rau was born in Germany and grew up in Spain. After obtaining a PhD in developmental biology at the European Molecular Biology Laboratory in Heidelberg, Germany, she studied journalism and went into science communication. Since 2008, she has been one of the editors of Science in School.
The Lesa21 website contains a very handy and convenient alphabetical list of topics and associated activities for primary school. A good number of these are not restricted to the science classroom, which makes integration between different subjects easier. The topics can therefore also be used as inspiration for interdisciplinary secondary-school projects.
The teaching activities detailed in this article may be used as a model of how real-life situations, in this case oil spills, can be used as a starting point for learning science. The article should be of particular interest to teachers in coastal areas, which are the first to suffer the consequences of such disasters.
The experiments are interesting and may be used on their own or in conjunction with other activities such as comprehension exercises and discussions. Questions to ask could include “What are the main challenges during an oil clean-up operation?” (e.g. weather conditions), and “What can we do on an individual level to minimise the possibility of such disasters?” (e.g. reduce oil consumption). One can also look at the implications for the individual, such as how to dispose of cooking oil, or how to clean something covered in oil.
Paul Xuereb, Malta