52 SSR September 2015, 97(358)

Practical work II

Plants: an ideal living material for teaching scienceDan Jenkins

ABSTRACT An understanding of the science of plants is of importance in enabling humanity to meet the ever-increasing demands on our global resources. Yet many students exhibit ‘plant blindness’ and an apathy towards learning about the science therein. Some examples of resources to overcome this and reposition plant material in the school science lesson are suggested and the usefulness of plant material in practical science is considered.

Good science teachers are always seeking better ways to engage their students with the subject they are learning. Many organisations, such as Science and Plants for Schools (SAPS), work to support teachers in this endeavour. SAPS focuses in particular on supporting secondary science teachers and technicians in the use of plants as the basis of science practicals. But given that plants have a reputation for being unpopular with young people, and practicals (biology in particular) take skill and planning to make them work, what makes plant practicals such a good option in the science classroom?

The role of plants in biology teaching

Several years ago, Tranter (2004) bemoaned the state of school students’ exposure to living organisms in UK science classrooms as being ‘little more than a potato and a geranium’. Lots of teachers seem unwilling to do plant-based practicals because of the unpopularity of plants as a topic among students. There is also a relatively small number of teachers with a plant science background. The introduction of a new series of curricula and examination specifications throughout England from key stage 3 to post-16 over the next few years presents an opportunity to revisit the use of living organisms in practical work and to reconsider the role that living plants can play in the science classroom and laboratory. By using plants to teach biological concepts other than those explicitly botanical (so using them to teach about enzymes, pathogens or genetics rather than just photosynthesis or plant transport), science teachers can introduce a whole host of

exciting practicals that would not be possible when teaching those topics in an animal context.

At SAPS, for the past 20+ years teachers, technicians and education experts have been working together to develop and support the teaching of biology in the classroom using members of the kingdom Plantae. In that time frame, meeting an increasing population’s demand for nutritious food has become one of the greatest challenges facing the world. Couple that with an unavoidable awareness of the effect humans have on the environment (particularly through agriculture) and one might assume that questions about how we develop, grow and protect plants would be at the forefront of students’ minds. However, many studies have shown that today’s young people exhibit the phenomenon of ‘plant blindness’ (e.g. Wandersee and Schussler, 2001; Nyberg and Sanders, 2014), with a disconnect between students’ perceptions of plants and the significant role they play in the biology of the living world.

Deep understanding of biology and respect for living organisms can be gained through practical work, and the value of practical work in science education has been explored many times (see, for example, SCORE (2008)). Observing and exploring the way plants, animals and microbes are composed and operate is an essential part of biology lessons, and plants provide straightforward and safe opportunities to observe, manipulate and investigate living processes in living tissue, from the cellular scale up to the whole organism (indeed, even at the field scale). Students can also take responsibility

SSR September 2015, 97(358) 53

for the reproduction, growth, nurturing and, yes, even death of plants in a way that directly engages them with the cycle of life and the science behind it. Given the great opportunities that plants offer for practically investigating living processes, could the apathy towards plants among young people be a barrier to their use for teaching purposes? If, as is likely, this apathy is caused by repetition of narrow, plant-based content in the curriculum then plant-based practicals offer the opportunity to extend plant teaching into new areas and provide new opportunities for students to experience at first hand many biological processes in action.

One such example where this apparent apathy was overcome is the Plants ‘r’ mint programme led by biology teacher Richard Spencer, a SAPS Associate (see Box 1 for further details about grants available to SAPS Associates). By giving each of his upper sixth-form students (aged 17–18) a living plant to nurture throughout their year of study, Spencer hoped to engage his students sufficiently deeply to enable them to appreciate the many processes going on in front of them. Dedicated to opening his students’ eyes, Spencer developed an entire A2 (the second year of A-level GCE) scheme of work, teaching biology through the context or related contexts of his students’ mint plants, an extract from which is illustrated in Box 2 (the full scheme of work can be accessed at the following link: saps.org.uk/secondary/teaching-resources/1262).

New opportunities for plant-based teaching in the curriculum

In England, the recent curriculum review at GCSE level (ages 14–16), new programme of study at key stage 3 (ages 11–14) and new subject criteria for A-level (ages 16–18) have allowed some innovation in the progression of ideas through the biology curriculum, and also provided opportunities for those refreshing their scheme of work for 11- to 14-year-old students to include alternative contexts for teaching science topics.

With new curricula and qualifications comes the spur for exploring new ideas and resources, even if teaching old concepts, and for biology teachers to delve deep into their own understanding of bioscience and their motivation for teaching it. For example, to a biologist the mechanism of photosynthesis is key to energy capture in the living world; the basic chemical

equation does little to convey the importance and complexity of the process, yet it is taught many times over. Maybe the reason plants are seen as dull by students is that they actually don’t see past this equation to the wonder that allowed the living world as it is now to evolve over millennia.

Jenkins Plants: an ideal living material for teaching science

BOX 1 SAPS Associate grants for resource development

UK teachers and technicians can apply for funding from Science and Plants for Schools to cover the costs of developing a teaching resource for the SAPS website. Resources range from quick lesson starters to substantial practical protocols, and grants are between £50 and £500. The costs of both time and materials can be claimed for. The SAPS team is able to offer support and advice regarding the resource development, including a network of subject experts based in plant science departments in universities around the country. See www.saps.org.uk/awards for more details.

BOX 2 Extract from Plants ‘r’ mint student sheets

The essential oils produced by mint plants are secreted by specialised cells and stored in circular structures called trichomes. The natural role of mint oils is to inhibit the growth of other competitor plant species (allelopathy), and to protect the mint plants from attack by insects and pathogens such as bacteria and fungi. Many of the constituent ingredients of these oils are known to disrupt cell membranes, thus making them more ‘leaky’.

Questions to consider reflecting on your mint plant:1 Suggest which components of cell membranes

could be altered or damaged by mint oils.2 Suggest why the cell surface membranes

of plants, insects, bacteria and fungi are all equally susceptible to damage by mint oils.

3 Suggest how mint oils could interfere with biochemical reactions such as respiration and photosynthesis.

4 Suggest why mint plants store the oils in specialised trichomes, rather than throughout the mint plant.

54 SSR September 2015, 97(358)

Over the coming year SAPS is developing a new approach to the English key stage 3 science curriculum to help embed further examples of biological processes or principles seen through a plant context. Additionally, this outline scheme of work presents topic areas across the programme of study of science (chemistry, physics and biology) presented within a plant context (see Box 3).

SAPS mainly develops practical resources that are appropriate for any teacher with the minimum of expense, additional equipment or specialist facilities (e.g. greenhouses) and with an output that is consistent, replicable and within a suitable time frame. No biology practical is perfectly reliable, and it is widely appreciated that unpredictable results can be used to teach something about the nature of science. For lesson objectives focused on whole-class teaching of practical skills and biological concepts, however, teachers and technicians do need inexpensive activities that generally go according to plan.

SAPS has developed well over 100 practicals, which come with technical support sheets, teacher instructions and student worksheets. All the

practicals have been tested by teachers and their technical teams to ensure they are appropriate for the school lab. Resources can be searched for on the SAPS website by age range and topic.

Many new schemes of work recommend continuing with long-standing practical activities, often because the equipment in schools and knowledge of these resources is widespread. New developments therefore take some time to embed, so to aid the uptake of new (or improved) practicals we have developed a series of videos, available on YouTube, to talk teachers and technicians through how the activity works, the expected outcomes and the required preparation. To help reduce the feeling that plant practicals always require hours of preparation and weeks of growing and recording data we also present a series of 2 minute practicals; see, for example, How do nettles sting? available at: saps.org.uk/secondary/teaching-resources/642.

Supporting, not supplanting, teacher expertise

Plants may be perceived as boring by students because of their lack of obvious movement, change or dynamic behaviours. The challenge then is to reveal how much is going on inside a plant and to create a link between observations from practicals and fundamental processes in biology. SAPS has created three animations – The movement of water and sugars in a plant; Respiration and photosynthesis; and Growth in a plant – which can all be accessed by students and teachers freely from the website or from the SAPS YouTube channel. On the advice of education experts, but to the surprise of some educators who have used the animations already, it was decided not to include full explanatory text or voiceovers in the animation. The aim was to enable teachers to illustrate the concept they were teaching, rather than replace their authoritative voice, and give them flexibility in terms of the depth of content they choose to introduce with different groups of students. A still from the animation series is shown in Figure 1.

Making the most of technician expertise and resources

Every quality science practical requires the support of a school science technician. Many of the resources developed for SAPS are developed in conjunction with or solely by technicians, as

BOX 3 SAPS key stage 3 outline scheme of work

Plants are an ideal context in which to explore scientists’ ideas of energy, matter and change. For example:l absorption of carbon dioxide gas from

the atmosphere by green plants during photosynthesis;

l release of oxygen gas, produced during photosynthesis, into the atmosphere;

l uptake of liquid water by plants and the loss of water vapour during transpiration;

l solubility of nutrients in soil water and their uptake by plants;

l making molecules from atoms: small molecules, e.g. O2, H2O and CO2; larger molecules, e.g. C6H12O6; giant molecules, e.g. DNA;

l shapes and structures of molecules represented using models;

l diffusion of substances in and between plant cells;

l materials cycles.

For the full outline scheme of work, see www.saps.org.uk/ks3.

Plants: an ideal living material for teaching science Jenkins

SSR September 2015, 97(358) 55

it is often left to technical staff to make sure that biology lessons have appropriate living material to carry out practicals.

For new ideas to be implemented in the school laboratory, many obstacles need to be overcome, and ideas for practical resources need to be ‘practical’ in terms of equipment and resourcing. SAPS judges every new idea against its criteria of being reliable, affordable, relevant and engaging (RARE), but also assesses its suitability for uptake given the normal provisions and budgets available to school science departments. Equally, the time required to prepare for a practical should be considered carefully; biology practicals can fare badly when the time required to prepare/grow or present materials in a suitable ‘living’ state can exceed weeks or months.

To do this well, SAPS and organisations like it need to be able to hear directly from teachers and technicians about the constraints and opportunities for practical work in their schools and colleges. We are tremendously grateful to our very committed group of practitioners to whom we can talk on a regular basis. It may be, however, that there is a need for more frequent and widespread consultation among teachers and technicians about

their needs, with the results made public so that resource developers can invest in projects that have real value.

One way to help achieve success in biology when using multicellular complex living organisms is to use materials that are available all year round. Plant material can easily be purchased at supermarkets, local aquaria or from reasonably priced suppliers that are able to supply throughout the year. For example, in resources using pondweed to investigate oxygen production it is suggested that one purchase a particular pampered tropical pondweed that is available from almost all aquaria, pet superstores and garden centres nationally, namely Cabomba (Figure 2). This pondweed will perform every time, bubbling freely. Although a small cost is involved in purchasing this fresh, it is far more consistent than pondweed taken from a school pond on a cold dark January morning to use in class – when the shocked plant is expected to ‘work’ five minutes later.

Studying plant processes or responses over a longer time frame presents another pressure, so plant species are suggested that operate on a timescale more appropriate to school timetables.

Figure 1 Still from the SAPS animation The movement of water and sugars in a plant

Jenkins Plants: an ideal living material for teaching science

56 SSR September 2015, 97(358)

Rapid-cycling Brassicas have been used in the classroom for several years now (see saps.org.uk/secondary/teaching-resources/126 and www.fastplants.org/about/history.php) but we are aware that their requirement for measurement over many weeks to observe, for example, the phenotype of an F2 generation in a genetics study, may not be possible for all schools. We are therefore

developing protocols to minimise this timescale, and have a modified version of the rapid-cycling Brassica protocol in development. SAPS is also investigating whether the lab rat of the plant world, Arabidopsis thaliana (thale cress, see Figure 3), is of use in the school classroom. This member of the Brassicaceae (cabbage) family is being used in hundreds of research labs around the world alongside other model plant species to investigate how and why plants work.

New curricula present science educators with an opportunity to challenge the apathy of students towards plants and for them to engage scientifically with this part of the living world. How many times in your students’ schooling do they get to explore living material practically? Plants offer an inexpensive but stimulating opportunity in the school laboratory, which should be explored to the maximum.

References

Nyberg, E. and Sanders, D. (2014) Drawing attention to the ‘green side of life’. Journal of Biological Education, 48(3), 142–153.

SCORE (Science Community Representing Education) (2008) Practical Work in Science: A Report and Proposal for a Strategic Framework. Available at: score-education.

org/media/3668/report.pdf.Tranter, J. (2004) Biology: dull, lifeless and boring? Journal of Biological Education, 38(3), 104–105.

Wandersee, J. H. and Schussler, E. E. (2001) Toward a theory of plant blindness. Plant Science Bulletin, 47(1), 2–9. Available at: www.botany.org/bsa/psb/2001/psb47-1.html.

Dan Jenkins is Project Manager at Science and Plants for Schools. SAPS is funded by the Gatsby Charitable Foundation and is based at the Sainsbury Laboratory, University of Cambridge. Email: dmj25@cam.ac.uk

Figure 2 Bubbling Cabomba

Figure 3 Arabidopsis thaliana (thale cress); photo: Sainsbury Laboratory, University of Cambridge

Plants: an ideal living material for teaching science Jenkins