Educational Modules for Increasing Indigenous Australian Students

Jun 19, 2019 - Educational Modules for Increasing Indigenous Australian Students' Involvement in ... which arises from their low participation in phys...
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Educational Modules for Increasing Indigenous Australian Students’ Involvement in Chemistry Colin A. Scholes* Department of Chemical Engineering, The University of Melbourne, Melbourne, Victoria 3010, Australia

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S Supporting Information *

ABSTRACT: Indigenous Australians are significantly underrepresented in chemistry based professions, which arises from their low participation in physical science subjects in secondary and tertiary education. This is a multifaceted issue with a number of identified solutions, one of which is to link chemistry with aspects of Indigenous culture. Here, four modules are presented that examine traditional Indigenous Australian practices in detail through a chemistry perspective. These modules assist students to better identify with chemistry principles and therefore encourage further inquiry. The first module is based on toxin removal from plant seeds through water solubility; the second is based on the medicinal properties of the tea tree, which results from isomers of organic compounds. The third module presents color hues of ochre pigments, which are dependent on inorganic chemistry, and the fourth module utilizes plant resin adhesive properties, which are based on glass transition temperatures. These modules have been assessed with Indigenous and non-Indigenous students, who demonstrated increased interest in chemistry. There is also encouraging evidence that these modules have assisted students in taking up additional chemistry subjects. KEYWORDS: High School/Introductory Chemistry, Laboratory Instruction, Hands-On Learning/Manipulatives, Student-Centered Learning, Minorities in Chemistry, Natural Products, Plant Chemistry, Dyes/Pigments

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INTRODUCTION Aboriginal and Torres Strait Islander people make a unique contribution to Australian society, given that many have strong connections to the land; their languages and their traditional knowledge form an integral part of the cultural identity of Australia. However, Indigenous Australians are marginalized and under-represented in many professional fields, most notably science, technology, engineering, and mathematics (STEM).1 This is similar to many other indigenous people in settler societies,2 such as New Zealand and the United States. Indigenous Australians make up 2.8% of the population of Australia3 but are estimated to be only 0.2% of the STEM workforce.4,5 This estimate includes Indigenous Australians in medical and associated health science fields, where decades of government and community support have increased their participation.6 Therefore, the number of Indigenous Australians associated with the physical sciences, such as chemistry, are believed to be even lower than this estimate. These statistics are similar to those in other settler-based societies, such as the United States,7 and lower than those for other minority groups in such countries.8 School completion rates and rates for transition to university based scientific degrees remain significantly lower for Indigenous Australians relative to those for their nonIndigenous peers, even though studies have demonstrated that Indigenous students are just as interested in science as their non-Indigenous peers.9 Part of the reason for this poor statistic is that 24% of Indigenous Australians live in remote or very remote areas,3,5 compared with 2% of the non-Indigenous population, and therefore do not have access to the high-level literacy and numeracy programs necessary for a successful scientific career. Many of the adolescents in these remote areas © XXXX American Chemical Society and Division of Chemical Education, Inc.

are taught traditional knowledge and customs, and it is into this framework that their understanding of STEM can be significantly improved by linking Indigenous practices with Western scientific concepts. This approach helps to overcome the discontinuity between Indigenous and Western scientific epistemology contexts.10 The inclusion of Indigenous voices in STEM is important because it is widely recognized that scientists and engineers need a wide range of experiences to enrich the pool of ideas from which excellence and creative solutions to problems are generated.11−14 Australia is not alone in this challenge, with the lack of representation of indigenous people globally in STEM and in chemistry in particular well recognized at the tertiary level,15 as well as the need for Indigenous people to retain their sense of culture while identifying with STEM fields.16 Here, four educational modules are presented that translate traditional Indigenous Australian practices with their associated chemistry explanations. These have been used to improve understanding of chemistry concepts and practices in secondary students of both Indigenous and non-Indigenous backgrounds within Australia. The objectives are to increase interest in chemistry in Indigenous students and to translate and transfer chemistry knowledge from the students to their elders through discussion of their traditional practices, thus increasing the contextual understanding of chemistry within the community. All four modules are designed to require minimal specialized equipment and can be undertaken in a general science classroom. Detailed student and instructor Received: March 10, 2019 Revised: May 9, 2019

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DOI: 10.1021/acs.jchemed.9b00207 J. Chem. Educ. XXXX, XXX, XXX−XXX

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Figure 1. Seedpods of Australian cycad (Macrozamia communis) plants.

guides for each module can be found in the Supporting Information. More broadly, these modules demonstrate the strong chemical knowledge and practices of Indigenous Australians in traditional settings, highlighting the strong awareness of their physical environment.

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MODULE 1: FOOD PREPARATION TO REMOVE A TOXIN THROUGH WATER SOLUBILITY Seeds from cycad (common Indigenous name: burrawang) plants are highly nutritious because of their starch content and traditionally been a valuable food source for Indigenous communities along eastern Australia (Figure 1). However, the seeds contain a toxin that is associated with motor neuron disease, which causes uncontrolled muscle twitching and gradual muscle weakening; this leads to difficulty swallowing, speaking, and breathing, resulting in death. The toxin and associated compounds also give the seeds a bitter taste, and hence Indigenous Australians have developed traditional methods to remove the taste (i.e., the toxin) before consumption. Two approaches are most common and are generally undertaken separately: • Leaching, in which the seeds are opened, and the kernels are sliced or ground. The resulting kernel powder is placed into a dilly bag (traditional Indigenous bag) and left in running water for several days. • Fermentation, in which the seeds are soaked for an extended period, up to months, in buried containers. The resulting pulp is eaten as a gruel or the flour is roasted into flat-bread. The toxin is β-methylamino-L-alanine (BMAA), which is produced by bacteria in a symbiotic relationship with the plant.17 The actual mechanism by which BMAA causes motor neuron dysfunction is not well understood, but it is thought to excessively stimulate nerve cells, leading them to be damaged and killed. There are currently no effective treatments available to counter BMAA poisoning. BMAA is found throughout the cycad kernel, which is a densely packed structure of polysaccharides, proteins, and fats. As an amino acid, BMAA is readily soluble in water through the carboxylic functional group as well as the primary and secondary amine groups, and BMAA resides within the kernel in its zwitterionic form (Figure 2). As such, BMAA will dissolve into running water through hydrogen bonding. However, the wettability of the kernel surface is poor,

Figure 2. Chemical structure of BMAA, with the carboxylic (red) and amine groups highlighted.

indicative of the hydrophobic nature of the kernel structure. This severely restricts the penetration of water into the kernel. Therefore, it takes a long time (days) for the kernel to become saturated enough for the BMAA present to dissolve into the penetrating water and then diffuse out of the kernel into the running water. The fermentation process takes the removal of BMAA further; as the toxin builds up in the surrounding water, yeasts involved in the fermentation process break down the BMAA molecule as part of their metabolism. Importantly, the water soaking approach does not affect the starch content of the seeds. This is because starch, as a polysaccharide consisting of multiple glucose units bonded together, is insoluble in water. The bonds between the individual glucose molecules require acidic conditions and enzymes to be broken. This occurs in the mouth, where saliva contains an enzyme (amylase) that starts the breakdown of starch into sugars, which continues in the stomach. The bitter taste associated with untreated cycad seeds is due to enzymes in saliva breaking down a part of the polysaccharide matrix on the kernel’s surface. This enables rapid releases of BMAA located near the surface of the kernel into saliva and onto taste sensors on the tongue. Leaching and fermentation do reduce the overall nutritional content of the seeds, as some vitamins and essential amino acids are also water-soluble and leach out with the BMAA. Students undertaking this module observe a demonstration of or partake in the preparation and leaching of cycad seeds (for a short period), during which the chemistry of water and the solubility and insolubility of organic compounds are presented, as well as the effects functional groups have on chemical properties and their importance in biological systems. The materials required for this module include cycad seeds, a mallet, and a filter bag. (Caution: Students with nut allergies B

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should check before undertaking this module.) The module methodology is the following: • Students separate the cycad seed from the cone (this can usually be achieved by hand if the cone has ripened or by a soft mallet). • Students open the seedpod to access the kernel (this generally requires the students to break the seeds against a hard surface or the use of a soft mallet). • Students lick the kernel to experience the bitter taste (students should not swallow the kernels). If the educator is concerned about BMAA (adverse effects are highly unlikely given the small amount the students will be exposed to), then they can prewash the seed kernels for a short period of time before having the students taste them. However, it is important that the students experience the bitter taste. • Students place the seed kernels into a small bag that can be closed (a traditional dilly bag is recommended, but jute, calico, bamboo, and natural fiber bags are also fine if the material is not water proof, i.e., no plastics). • Students expose the seed filled bags to running water for 30 to 60 min (this is usually done by hanging the bag under a running faucet). • During this period, the chemistry of the bitter taste and the purpose of the running water are explained; principles of organic chemistry and water solubility should also be introduced. • Students remove the seed kernels from the bag at the end of the 30−60 min period, dry the seeds with a paper towel or cloth, and then lick the kernels again. They should report that the bitter taste has gone (student should not swallow the kernels, as the limited water exposure time has only removed BMAA from the surface regions of the kernels). Students undertaking this module develop an appreciation of traditional food preparation and an understanding of organic chemistry and are able to predict the water solubilities of naturally produced chemicals. This module can be applied to other bitter tasting nuts for which exposure to water removes the bitter favor. However, the chemistry of the bitter flavor will be different for each nut and generally associated with alkaloids present. A good example of an alternative nut is the cocoa bean, the source of chocolate.

The tea tree is native to eastern Australia and is not related to Camellia sinensis, the source of beverage tea. The leaves of the tea tree are used for treating a range of skin conditions, such as acne, eczema, and psoriasis, as well as for soothing skin irritations and wounds (Figure 3). The crushed leaves are also

Figure 3. Leaves from the Australian tea tree.

used to treat dry scalp and dandruff and fight fungal infections such as athlete’s foot, jock itch, and toenail fungus. Today, essential oils are extracted from the leaves and used to treat these conditions, as well as to fight viral infections such as influenza and recurrences of the herpes virus.22 These treatments take advantage of the organic chemicals within the tea tree leaves that display antiseptic, antifungal, and anti-inflammatory properties; their chemical compositions make them easily absorbed by the skin upon extended contact with the leaves or, in modern situations, tea tree oil, as they pass from the oil residue through the epidermis. Tea tree oil has been identified as consisting of 100 different chemical compounds that all play some roles in these therapeutic properties, with the most active ingredient associated with a class of chemicals call terpenes.23 These are a class of hydrocarbons that are composed of isoprene units linked in regular or irregular continuous chains, which are generally closed to form ring structures (Figure 4). Tea tree oil mainly consists of three active chemical compounds: terpinen4-ol, (α,γ)-terpinene, and α-terpineol. The antibacterial and antifungal properties are mostly associated with terpinen-4-ol, (α,γ)-terpinenes, and α-terpineol, which have been shown to damage and disrupt the cell membranes and walls of bacteria and fungal spores.16 This results in protein and genetic material being lost from the cell, known as cell lysis, which effectively kills the bacteria or fungus. How these chemical compounds achieve this is still not fully known. Terpinen-4-ol and α-terpineol are known as monoterpene alcohols because they consist of two isoprene units and an alcohol functional group (OH). These two chemicals have the same chemical formula, C10H18O, and the same molecular weight (154.25 g/mol) but different chemical structures and hence are known as chemical isomers. Similarly, (α,γ)-terpinenes are chemical isomers, in that they have the same chemical formula and molecular weight but different structures; the α and γ denote the positions of the double

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MODULE 2: MEDICINAL PROPERTIES OF THE TEA TREE PLANT EXAMINED THROUGH ORGANIC CHEMISTRY Indigenous Australians use a wide range of native plants for medicinal purposes. Examples are kakadu plums (billy goat plums, Terminalia ferdinandiana) for treating illness, which is partly attributed to the plums being the world’s richest source of vitamin C, and kangaroo apples (Solanum aviculare), which are used to treat swollen joints. Washed emu bush (Eremophila nivea) leaves are used to treat sores and cuts, whereas breathing in smoked emu bush leaves is used to assist with congestion because the leaves contain antibiotics.18 Eucalyptus leaves are used to treat body pains, fevers, and chills, which resulted in today’s eucalyptus oil industry. This module focuses on the medicinal plant tea tree (Melaleuca alternifolia), which has antiseptic, antifungal, and anti-inflammatory chemicals.19−21 C

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Figure 4. Chemical structures of terpinen-4-ol, (α,γ)-terpinene, and α-terpineol, based on isoprene.

Figure 5. Indigenous rock art from the Pilbara region of northwestern Australia.

bonds within the ring structure. Isomeric forms and small changes in chemical structures have significant impacts on chemical properties and interactions with biological systems. The materials required for this module include tea tree leaves, a mortar and pestle, cooking oil, and leaves from a control plant. The module methodology is the following: • Students remove the leaves from branches of the Australian tea tree bush. • The leaves are then separated into two piles. One pile of leaves is crushed by hand. The other pile of leaves is mashed, and a small amount of cooking oil is added (canola and olive oil are recommended). This results in a paste and is similar to traditional methods. The finer the leaves are mashed, the better the paste, which should have the consistency of toothpaste. • Leaves from another plant can also be supplied to the students as a control and crushed by hand (they should be nonfragrant and nonoily). Examples are citrus, oak, and ash leaves. • The crushed tea tree and control leaves are applied to the students’ forearms and rubbed on the skin, with each sample separated by at least 3 cm. • The students should experience soothing moisturization of the skin exposed to the tea tree leaves, whereas the control leaves have no effect. • Medicinal and organic chemistry is then presented to the students; the roles functional groups have on properties and their different solubilities are presented. • Students then apply the tea tree paste to their opposite forearm and leave it for 10 min. • The students should experience a more intense soothing and moisturization experience as well as fragrance from

the paste. Removal of the paste by washing leaves the treated skin notably softer. Students undertaking this module demonstrate and partake in the applying of tea tree leaves (or oil) to the skin and describe any perceived outcomes. They are taught that chemical compounds can have medicinal purposes and that the chemical structure is important for those properties. They are also introduced to more complex organic chemistry in terms of functional groups, cyclic structures, and chemical isomers. Students undertaking this module also develop an understanding of biological chemistry and learn traditional salve preparation techniques. This module can also be applied to several herbs for which the leaves have readily identifiable flavors or smells. Good examples of alternatives are the mint family, such as spearmint and peppermint, for which the extraction of menthol and terpenoids into the paste will be easily noted by the students through smell.

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MODULE 3: OCHRE PIGMENTS FOR NATIVE ART INVESTIGATED THROUGH INORGANIC CHEMISTRY Indigenous art has a distinctive form developed over tens of thousands of years. This art is most famously applied as rock and canvas paintings and is also utilized in body art and on apparel (Figure 5). These visual depictions often have strong cultural significance, linking Indigenous communities with their history and environment. Hence, many Indigenous students strongly identify with and appreciate this art. The distinct red, brown, and yellow pigments of this art are associated with ochre, a clay consisting of sand and various forms of ferric oxide.24 The ochre pigment comes from D

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Figure 6. Ochre pigment hues and associated chemistry changes.

the binder material breaks down over time, and artwork survival is dependent on the surface, pigment chemistry, and exposure to the elements. Charcoal (black) is the first pigment to be lost, followed by kaolinite (white), then yellow ochre, red ochre, and finally dark red ochre. This is the reason why many old Indigenous rock art is primarily red in color, because age and deterioration have removed the more susceptible pigments. The materials required for this module include yellow and red ochre (obtained from art suppliers), a mortar and pestle, honey, charcoal, a sealed container, and a heat source. The module methodology is the following: • Students receive yellow and red colored dried ochre powder. • A small amount of water is added to this powder to make a paste (students add water slowly and continue stir with a brush). To this paste, students add a small amount of binder (honey is recommended because the students will be familiar with it). • The students are then asked to change the color (hue) of the ochre paste (paint), through two approaches: (1) grinding the ochre paste to reduce the particle size and then heating the paste within a closed container that has a vent to keep atmospheric pressure (∼80 °C) and (2) adding a small amount of ground charcoal particles to the ochre paste and then heating the paste within a closed container that has a vent to keep atmospheric pressure (up to 150 °C). If a small container is not available, wrapping the paste in aluminum foil and applying heat will achieve a similar result. • Students observe a change in the color of their ochre paste over time (15−60 min, depending on the heating rate, temperature, amount of charcoal, and grinding action). Students should only open the heating containers sparingly, as oxygen limits the reduction process. • During the waiting time, inorganic chemistry should be presented, iron complexation and ligand chemistry should be discussed, and the theory behind inorganic compound spectroscopy should be introduced. • Once the color change in the ochre is observed, students remove the paste or particles from the heat and add more water to ensure consistency of the paste. • Students then are given the opportunity to paint with the range of colors generated. If possible, an Indigenous artist should be present to instruct students on traditional techniques. Students should add only a small amount of charcoal to the paste, as it is not necessary to reduce all the ochre to observe a color change. Too much charcoal darkens the ochre, and the color change is not as vivid.

naturally occurring minerals and can range in colors from yellow and orange to purple. The distinct colors are achieved through different chemical forms of ferric oxide as well as the relative grain size of the clays during their mixing in the water paste before being applied. The yellow color is strongly associated with hydrated iron oxide-hydroxide (FeO(OH)·nH2O), which is associated with the mineral limonite. The nH2O designates that a number of water molecules are associated with the iron complex. This is important to the color, as heat treatment of yellow ochre results in a color change to orange, red, and umber hues. This traditionally was achieved from iron oxide rich rocks being exposed to heat and charcoal within a campfire environment. This generated reducing environments on the iron oxide complexes, which enabled them to lose both water modules and oxidation states. Hence, water molecules being lost from the iron complex creates monohydrate iron oxide-hydroxide (FeO(OH)·H2O), which has one water molecule, and further heating generates anhydrous iron oxide-hydroxide (FeO(OH)) and then iron hydroxide (Fe(OH)2). These changes in the chemical functionality of the iron ligand alter the light absorbance properties of the ochre powder collected from the campfire rocks and achieves the different color ranges (Figure 6). Red ochre is iron oxide (Fe2O3), which is known as the mineral hematite; it is also the main component of rust. It is the second most common pigment, especially in Indigenous paintings of western and northern Australia, given the large iron ore deposits. Purple ochre is also based on iron oxide, but it is associated with smaller clay particle sizes, which enables blue light to be strongly scattered. This blue scattering combined with the red absorption of the iron oxide results in the purple hue. There are ochre pigments associated with green and turquoise hues, but these are very rare and only associated with one or two natural deposits within Australia. This means that these colors are only used on important ceremonial occasions and were traded significantly throughout Australia in precolonial times. To achieve black, charcoal is used and sourced traditionally from fire pits. The elementary carbon gives the black appearance, and this is still used today in pencils, where carbon is in the form of graphite. The color white is achieved through the clay kaolin (Al2Si2O5(OH)4), a very common mineral based on silicate. Kaolin is still used today in ceramics, paper, toothpaste, and paints to provide white coloring. The ochre pigments are made into pastes, and binders are added to ensure consistent mixtures are formed, resulting in reliable coatings. Traditional binder materials have been plant resins, sap, honey, eggs, blood, saliva, and animal fat. However, E

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chemicals in addition to the pinene based polymers; one critical component is cellulose, composed of long thin plant fibers that have diameters of less than 10 nm. Cellulose’s presence within the resin adds mechanical support that enables the resin to remain strong and elastic at elevated temperatures even in its rubbery state. The adhesive bond is associated with intermolecular bonding between the resin polymer and the sealing object. The strength of this adhesive is due to the number and magnitude of the intermolecular interactions that are possible between the long-chained resin and the bonding surface. The greater the surface area and the cleaner the area, the stronger the adhesive bond between the resin and the surface. Critically, there is no chemical reaction between the resin and the object’s surface, and hence the resin seal can be removed if reheated above the glass transition temperature. Spinifex resin is known as a thermoplastic adhesive, similar in properties to commercial synthetic adhesives on the market. The materials required for this module include spinifex straws, aluminum foil or equivalent, a heat source, and objects to adhere together (e.g., stones). The module methodology is the following: • Students remove straws from bushels of spinifex brush, straighten each straw, and collect them as a bundle. • The spinifex straw bundle is then threshed onto a sheet of aluminum foil (generally spread over a table). Students will observe small globules of resin form on the foil. • After 10 min of threshing, students remove the aluminum foil from the table and apply heat underneath it. The traditional approach uses fire, but a hot plate is safer (∼80 °C). • Students then collect the resin globules together into one ball. Caution: the resin and foil will be hot; students should use leftover spinifex straw to guide the globules around. • Students allow the resin ball to cool to a temperature at which it is safe for the students to handle the resin. Then, students are allowed to alter the shape of the resin: (1) To demonstrate the adhesive properties, students can squeeze the resin between two objects that the students’ wish to be joined. (2) To demonstrate the thermoplastic properties, students can shape the resin into a mold. • After the students handle the resin, they allow the shaped resin to cool to room temperature. During this period, students should be introduced to the concepts of macromolecules and polymers, intermolecular bonding, and physical properties, as well as how adhesives work. • Once the resin is cold, students then test the adhesive strength and mold shape through manual handling to determine the physical properties of the resin. The students should notice significant hardening of the resin at room temperature and strong adhesive action. • Students can then reheat their resin to return it to a more malleable material (adding moisture by massaging with wet fingers helps) and then rework the resin into a new adhesive bond or mold and begin the process again. Students undertaking this module remove the resin from the plants, heat the product until it is flexible, and then mold the resin into various shapes or use it as an adhesive. Students can also undertake this module with other natural resins like

During this module students are taught the principles of inorganic chemistry and are introduced to the importance of iron complexation, hydration, and ligand chemistry, as well as the reason why inorganic compounds provide vivid colors. Ochre pigments and palettes are commercially used in a wide range of paints and associated products, such as makeup. Instructors should have no difficulty in obtaining these materials from good art suppliers. Hence, this module can be readily undertaken globally.

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MODULE 4: ADHESIVE PROPERTIES OF THE SPINIFEX PLANT RESIN BASED ON THE GLASS TRANSITION TEMPERATURE Traditional Indigenous tools and weapons, such as axes, spears, and the woomera (traditional spear thrower), utilized resins (adhesives) in their construction to connect stones and wood as well as to bond wood and wood together. The material for the adhesive was sourced from spinifex grass species, as many are extremely resinous.25 The straw from spinifex plants (Figure 7) is harvested from the plant and then threshed to

Figure 7. Spinifex (Triodia intermedia) plant in the Australia interior.

remove and separate out the resin particles. The resin is then heated over a fire, which fuses the particles together into a tar that is moldable while warm. Cooling of the tar sets the resin, which then acts as a very strong adhesive. If the bond needs to be resealed, the resin can be softened through heating with the addition of water, which allows the resin to be remolded before cooling sets it again. Resins are polymers that consist of basic chemical structures (monomers) that are continually repeated along a chain. The resin from the spinifex plant is associated with a pinene structure repeating unit and generally has a very high molecular weight. The resin is produced by the plant to provide protection against insects and pathogens. The chemistry aspect of working with spinifex resin is that the changes in properties observed under heating are due to physical properties and not a chemical reaction. Importantly, the resin passes through its glass transition temperature at a relative mild elevated temperature. This transition is associated with a decrease in the strength of the intermolecular interactions between segments of the polymer chain. This weakens the structure, enabling particles to aggregate and be molded into various shapes, which is associated with a rubbery polymer state. Cooling reasserts the intermolecular bonds, and the resulting structure becomes strong, which is associated with a glassy polymer state. The resin also contains a range of other F

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to enable tactile and kinesthetic based students to fully engage with the subject material. Anecdotal evidence has indicated that the modules are well received by students, encourage them to think about traditional practices in a scientific manner, and encourage students to pursue STEM based careers. Continual application of these teaching modules with Indigenous and nonIndigenous students is expected to increase participation in chemistry and related subjects at secondary and tertiary education levels. Similar educational modules can be developed from indigenous cultures in other settler based societies, as many of the fundamentals of the modules developed here are applicable in those countries (toxin removal for food preparation, medicinal properties of plants, and pigment and material production). The development of such modules should follow a similar pathway to that undertaken for many educational modules around Indigenous knowledge, including those presented here. There needs to be a clear willingness of all parties to build on traditional knowledge, translate the practices for a nonindigenous audience, and understand the science. It is hoped that such educational modules will develop in other settler based societies in the near future and in other scientific disciplines.

beeswax, which displays similar properties and chemistry. As a part of this process, students are taught the principles of polymer chemistry and the impact polymer length has on physical properties, as well as the nature of intermolecular bonding. Upon cooling of the resin, the students are asked to deform the structures they have made. This enables a comparison of relative mechanical properties of the resin and the strength of the material, which enables a discussion on the material properties to be presented, given the students handson experience. This module can also be undertaken with other plant’s resins and gums but not with rubbery latex. The resin must be extracted from the leaves or by tapping the bark of trees, which demonstrates both adhesive properties and a rubbery transition with temperature. Examples of potential resins that can be used are those from juniper, pine, and fir trees. For all four modules, there is the possibility of replacing the key Australian component with an alternative to enable similar modules be undertaken in other countries. In these situations, it is vital that the chemistry of the replacement system be verified for the module, as it may be that the methodology is very similar, but the underlying chemical mechanism is different. It is also recommended that educators in other countries liaise and collaborate with Indigenous people in their respective countries to find similarities in the learning modules presented here.

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STUDENT OUTCOMES Students (ages 12 to 15) from both suburban and rural secondary schools in Australia have undertaken the four modules in class sizes ranging from 10 to 25 students. The majority of students identified as non-Indigenous, and schools in remote communities have not yet trialed the modules. In all cases, students valued the practical aspects of the modules, the link between the practical and theoretical chemistry, and their gaining better understanding of Indigenous customs and culture. Student feedback about the modules during the early testing phase was overwhelmingly positive, with some of the following comments received: Taste testing of the seeds [cycad] before and after washing in the water was great, as I’ve never tasted anything in science class before. Changing the ochre colour by heating with charcoal was fascinating, as we tried to turn red into purple. The colour changes in the ochre made it clear to me how Aboriginals made their rock paintings, and the great skill and effort they applied to their art. The spinifex balls [resin] are like sticky playdough and its pretty amazing Indigenous were using this as glue 10,000 years ago.

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ASSOCIATED CONTENT

S Supporting Information *

The Supporting Information is available on the ACS Publications website at DOI: 10.1021/acs.jchemed.9b00207. Detailed students’ guide for undertaking each of the four modules (PDF, DOCX) Instructor’s guide (PDF, DOCX)

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AUTHOR INFORMATION

Corresponding Author

*E-mail: [email protected]. ORCID

Colin A. Scholes: 0000-0002-3810-2251 Notes

The author declares no competing financial interest.

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ACKNOWLEDGMENTS C.A.S. acknowledges the support of an Australian Government Endeavour Fellowship. REFERENCES

(1) National Indigenous Engineering Summit, 18−19 June, 2015. The University of Melbourne. https://conference.eng.unimelb.edu.au/ national-indigenous-engineering-summit/ (accessed June 2019). (2) Woods-McConney, A.; Oliver, M.; McConney, A.; Maor, D.; Schibeci, R. Science engagement and literacy: a retrospective analysis for indigenous and non-indigenous students in Aotearoa New Zealand and Australia. Res. Sci. Educ. 2013, 43, 233−252. (3) 2016 Census. Australian Bureau of Statistics. www.abs.gov.au/ websitedbs/censushome.nsf/home/2016 (accessed May 2019). (4) Excellence & Equity in Mathematics; University of South Australia and AAMT: Adelaide, 2015. (5) Winthrop, J. M. Indigenous engagement with science: Towards deeper understandings; Inspiring Australia: Canberra, 2013. (6) Page, K.; Hattam, R.; Rigney, L.-I.; Osborne, S.; Morrison, A. Strengthening Indigenous participation and practice in STEM: University

CONCLUSION

Indigenous Australians are significantly underrepresented in the chemistry profession. This is due to a variety of factors, of which the discontinuity between formal science education and traditional Indigenous education is a major cause, especially for remote communities. Here, four chemistry education modules are presented that translate traditional Indigenous practices into their equivalent chemistry explanations. These modules were designed to help bridge the comprehension gap for Indigenous students and provide a strong practical component G

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DOI: 10.1021/acs.jchemed.9b00207 J. Chem. Educ. XXXX, XXX, XXX−XXX