Welcome to the third instalment of our ‘Making it Relevant’ Series.
Firstly, we are going to take a look at why we teach Atoms & Radiation at GCSE. Then the content typically required in the new GCSE specifications will be summarised. Finally we will be thinking about how this can be made engaging and relevant to all our students.
Ultimately, this topic is about the reason we are all here. Fusion in the Sun is the process that keeps Earth flourishing, although it is only a tiny part of this topic. The actual topic is called ‘Atomic Structure’ but this can mislead students into confusing it with chemistry; Atoms & Radiation seems a less ambiguous option. Radioactivity is a topic that the general public and the media can hold very strong views about. Therefore it is important that we help our students in developing a sound understanding of the genuine nature of this phenomenon. Enabling the future nuclear scientists to develop new, safe and innovative ways to harness the power behind radioactive emissions and processes. Removing the fear of nuclear medicine. Allowing intelligent and productive debate within the population about the merits and risks associated with using nuclear energy to generate electricity.
There are five main topics in the specification:
The structure of the atom, with an emphasis on the nucleus. The chemists are concerned mainly with the outer electrons so it is important to make the distinction clear to students. Isotopes are covered so students understand that not all atoms are unstable. Ions and ionisation are also included because it helps with understanding the damage nuclear radiation can cause to cells.
Development of atomic model
Students will be tracing a timeline through history; investigating how we came to know what we do about the atom when it is too small to look at.
The different emissions that can come from an unstable nucleus, including neutron emission, form the basis of this section. Students will be looking at the range, penetration and ionising power. This will be used, in conjunction with an understanding of half-life and radiation dose, to discuss the pros and cons of using radioactive sources in various scenarios. Students will also be asked to use decay equations for alpha and beta emission.
Hazards (background, contamination, irradiation)
You will be introducing the concept of background radiation and what contributes to it. Students will be considering the precautions taken to prevent contamination and irradiation from radioactive sources.
Fission & Fusion
Using fission in a controlled and uncontrolled manner, along with the positive and negative outcomes of using nuclear reactors to generate electricity. The process of fusion in the sun is included here.
The majority of students are likely to be aware of the negatives associated with radiation, which means they could struggle to become engaged with the topic. This misconception might be an excellent starting place. You could try showing them some of the positive impacts nuclear science has on our everyday lives before progressing too far into the topic. This could be as simple as a slide show depicting the uses of radiation beyond electricity generation and nuclear weapons.
Teaching the atomic structure content first is necessary, to enable the development of the ideas later in the topic. There are many opportunities for modelling in this section. Students can not see atoms, so it is helpful for them to create their own models that they can touch and manipulate (it can also generate some beautiful work to display on your walls).
Similarly, the development of the atomic model can be documented graphically. Students could be divided into groups and allocated one model, investigating and reporting back to the class, or as a ‘marketplace’ activity. Alternatively everyone could create their own representation of the ‘story’ using resources spread around the classroom that they have to move around to locate.
The types of emissions from unstable nuclei could be demonstrated with animations or with a model. Below is an example of a felt model, made with magnets so it can stick to a whiteboard. It can be effective in showing the changes in the mass and charge of the nucleus when emission happens; along with showing the relative sizes of the particles emitted and the effect this may have on their range, penetration and ionising ability.
Background radiation has man-made and natural components, which need to be identified by students. You could provide students with data on the dose provided due to location, elevation, building materials, medical uses, fallout and food, then see if they can work out their annual dose of radiation. There are several example of nuclear accidents (man-made: Chernobyl; natural events: Fukushima) contributing to current background radiation levels, along with the precautions taken to reduce contamination and irradiation of the population. The positives can be hard to find in these scenarios, but it is important to establish both so students can start making up their own minds about the use of fission reactors. The recent announcement that the Chernobyl site may become a huge Solar Farm has potential for discussion.
This topic has many areas to engage your students in debate and discussion, keeping the balance between positive and negative impacts. It might be interesting to poll your students before and after the topic to see if their thoughts and feelings on radioactivity have been altered by your teaching.