On rare occasions, students might unknowingly bring samples of hazardous materials to school. Some schools may also have these materials on-site, sometimes as part of their buildings, or well-marked and stored safely. On occasion they may be as yet unidentified or stored improperly.

Asbestos

Asbestos is composed of long thin fibrous crystals that easily break off and are harmful if inhaled. Unfortunately, asbestos is occasionally found in some mineral kits, including those recently purchased, posing a risk to safety. It may appear under a variety of names. Follow Worksafe’s Asbestos in Mineral Kits advice.

Asbestos was commonly used in building and fire-proofing materials and is still found in situ in older buildings and schools today. In good condition and undisturbed, these buildings are unlikely to present a health risk.

Crocoite

Crocoite can be identified by its brilliant orange-red colour and crystals that are transparent to translucent. The crystals may be several centimetres long, or only a few millimetres long. The mineral is Tasmania’s official state mineral and is mined in Dundas on the west coast of Tasmania. Crocoite mineral specimens can be purchased at gem shows around Australia and may be acquired for their beauty without buyers being aware of the associated risks.

Crocoite is highly toxic and harmful if ingested or inhaled. Handling should also be avoided as crocoite is a lead chromate. It also poses a fire hazard as it can ignite spontaneously when exposed to heat.

Lead

Lead is a heavy, soft, silvery white or greyish metal. It is mostly found in the mineral galena, which may be unknowingly acquired at a gem/mineral show. Although now banned, schools may occasionally still have small sheets of lead foil which is thicker than standard aluminium foil.

Lead mainly enters the body by swallowing and breathing lead-contaminated particles. It accumulates in the body and can eventually cause serious health problems. Children under the age of six are particularly susceptible to the effects of lead poisoning.

Mercury

Mercury is a silvery-white liquid. Although banned in schools, it may occasionally be found in a small bottle in a school chemical storage area or in traditional thermometers and barometers. Breakage and spillage requires quick and effective clean up, as mercury will vapourise at room temperature and is hazardous to breathe.

The video above contains photographs which may support you to identify these hazardous materials.

When planning for teaching in your classroom, it can be useful to see where a sequence fits into the larger picture of science. This unit is anchored to the Science Understanding core concepts for Earth and Space Sciences.

• The Earth system comprises dynamic and interdependent systems; interactions between these systems cause continuous change over a range of scales

In Year 3, this involves comparing the observable properties of soils, rocks and minerals and investigating why they are important Earth resources.

This core concept is linked to the key science ideas:

• Similarities and differences can be used to sort and classify soil, rocks and minerals. (Patterns, order and organisation)
• The observable form of nonliving things (rocks, soil and minerals) can change over time (as a result of energy and forces). (Matter and energy)
• Components of soil, rocks and minerals and their interactions can be described. (Systems)
• Rocks, soil and minerals exist at different scales. (Scale and measurement)

When your students next progress through this core concept, they will identify sources of water and describe key processes in the water cycle (Year 4).

Minerals are part of the building blocks of the Earth, and most rocks contain minerals.

Whilst students may have heard the term ‘minerals’ in a variety of contexts, it is unlikely they will have the prior knowledge and experience to be able to identify or distinguish them in the rocks they find. For this reason, the idea of minerals is omitted from this Launch lesson, as the Launch phase focuses on tapping into what students already know.

Australia is a mineral-rich country, however, and is one of the world's leading producers of bauxite (aluminium ore), iron ore, lithium, gold, lead, diamond and zinc (to name just a few). Many people in Australia are involved in the mining and processing of these minerals, and for many towns and cities these industries play a significant role.

Therefore, it may be suitable for your context and students to expect students to be able to identify some minerals during their geology quest, or ask them what they know about them. You might also ask about specific minerals that students may have knowledge about.

An adaptation of the well-known KWL chart, a TWLH chart is a learning tool used to elicit students’ prior knowledge by asking what they Think they know, determine questions students Want to know answers to, document what has been Learned, and How students know they’ve learned. 

One of the key aspects of a TWLH chart is its ability to guide a student in metacognitive (the ability to think about your thinking) processes. By focusing on what students think they know, they are prompted to see learning as a journey, where new scientific evidence and experiences might change your thinking. This is a very important aspect of thinking scientifically.

In this instance, students are considering their initial knowledge about rocks and soils. In this phase of learning, students should be encouraged to populate the T and W sections of the chart.

Taking account of students’ existing ideas is important in planning effective teaching approaches which help students learn science. Students develop their own ideas during their experiences in everyday life and might hold more than one idea about an event or phenomenon.

Students might think that the Earth’s crust consists mainly of soil with some rocks embedded in it. However, the Earth’s crust is primarily rock, with a thin layer of soil on top which varies in thickness.

When describing a set of rocks and minerals, students almost never use the term ‘mineral’, and anything sparkly and shiny is often referred to as a ‘crystal’. Students often name pieces of mineral crystal such as amethyst, turquoise and jade as ‘gems’, unaware that in fact gemstones are simply cut, shaped and polished minerals, and rocks are made up of one or more minerals.

Many primary and secondary students mistakenly believe that soils have always existed and originated ‘when Earth formed’; that it ‘continues for miles underground’ and remains ‘unchanged over time’¹. This is because the rates at which soils form can be very slow. However, untended house gutters may develop a thin layer of soil in just a few years.

This sequence is students’ first introduction to the composition of the Earth. As such, it addresses the alternative conceptions outlined above in a broad sense, by giving students the opportunity to explore, think and learn about soils, rocks and minerals in a more formal way than they may have previously.

In Year 3 students’ learning about soil focuses on the importance of soil as a resource and the observable properties of different soils, including colour, texture related to particle size (sticky clay, gritty sand and/or smooth silt) and structure (clumping of particles, organic matter—decaying plants and animals—and visible soil organisms like earthworms).

Students will extend their understanding in Year 4 when they learn about decomposition of organic matter and begin to make links back to composting, earthworms, or the breaking down of leaf litter. This will help them to develop the concept that soil changes over time. 

In Year 5 students study weathering, erosion, transportation and deposition which continues to build on the concept of soil, rocks and minerals as ever-changing over varying time scales.

¹Skamp, K., & Preston, C. (2021). Teaching primary science constructively (7th ed.). Cengage Learning Australia.

The study of rocks and minerals and Earth’s geological processes is covered progressively in the Australian Curriculum and the timing is heavily guided by the students’ ability to understand relative size and rates of change. Younger students often find it difficult to work with scales outside their everyday experience—these include the vast distances in space, the incredibly small size of atoms, and the slow processes that occur over geological time. As students progress from Foundation to Year 10, their understanding of relative sizes and rates of change develop, and they conceptualise events and phenomena at a broader range of scales. They progress from working with scales related to their everyday experiences to working with scales beyond human experience. 

The rocks, soils and minerals students learn about in this sequence have been formed, and change, over vast periods of time that students are not expected to be able to understand at this year level. This sequence focuses on the composition of rocks, soils and minerals at the time that students examine them, and how they might be changed over the course of days, weeks and months (for example by adding compost to soil to improve its structure) rather than what happens to them over longer time scales.

The table above shows the relevant Earth and Space Sciences content descriptions from the Australian Curriculum: Science, alongside how they align with students’ ability to understand relative size and rates of change.

An Earth table contains samples collected by students that showcase the pieces of the Earth that support life, such as soil, sand, clay, humus, rocks, and minerals.

Earth tables can be intriguing to many students and something they can all experience success contributing to. They provide an opportunity for students to notice similarities and differences in objects, and to share their knowledge and experiences, reinforcing that we value them and their understandings.

Special items may need to be returned to students—a collection of small boxes/tubs/trays can help to keep those items sorted and named while on the table.

As a class, ensure everyone knows which items they are allowed to touch. Or it can be simpler to only permit items onto the table that can be touched by everyone, to encourage free exploration.

The colour of some rocks can be accentuated by wetting the rock. Providing a tray with paint brushes/sponges and water is a simple way for students to observe and enjoy this. Some softer rocks and minerals are easily damaged by water—explaining this to students and clearly identifying which rocks can be used on the water tray will avoid accidental damage to rock enthusiasts’ collections.