4th Sep '25

Schemes of Work

P1
- P1.5
  - Lesson 01 - How has the model of the atom changed over time? Lesson Plan Lesson Title
    - New experimental evidence may lead to a scientific model being changed or replaced.
    - Before the discovery of the electron, atoms were thought to be tiny spheres that could not be divided.
      - Suggested Activity:
        Produce a timeline to show how our ideas about atoms have changed since ancient Greek times.
        
        Find out about the origins of the words protons, neutrons and electrons.
    - The discovery of the electron led to the plum pudding model of the atom.
    - The plum pudding model suggested that the atom is a ball of positive charge with negative electrons embedded in it.
    - The results from the alpha particle scattering experiment led to the conclusion that the mass of an atom was concentrated at the centre (nucleus) and that the nucleus was charged. This nuclear model replaced the plum pudding model.
      - Suggested Activity:
        Model the alpha scattering experiment using marbles and an upturned tray lifted just off the table with a hidden small mass in the centre.
        Roll the marbles (alpha particles) under the tray and note down how many go straight through, how many deflected slightly and how many deflected straight back.
        Use these observations to come up with a model of what is under the box (model of the atom). Mimicking Rutherford.
        
        ---OR---
        
        by flicking a 1p coin through stack of 2p coins. The 1p coin represents the alpha particle and the stack of 2p coins the gold foil. How must the stacks be arranged in order that 90% of the coins go straight through without scattering? What conclusion can be drawn about the arrangement of atomic nuclei in a material and the amount of free space between nuclei?
        Equipment Required:
        Rutherford alpha particle scattering demo (upturned tray with hidden small box and marbles).
        
        ---OR---
        
        1p pieces and 2p pieces.
    - Niels Bohr adapted the nuclear model by suggesting that electrons orbit the nucleus at specific distances. The theoretical calculations of Bohr agreed with experimental observations.
      
      Details of experimental work supporting the Bohr model are not required.
    - Later experiments led to the idea that the positive charge of any nucleus could be subdivided into a whole number of smaller particles, each particle having the same amount of positive charge. The name proton was given to these particles.
    - The experimental work of James Chadwick provided the evidence to show the existence of neutrons within the nucleus. This was about 20 years after the nucleus became an accepted scientific idea.
      
      Details of Chadwick?s experimental work are not required.
    - Students should be able to describe why the new evidence from the scattering experiment led to a change
      in the atomic model.
    - Students should be able to describe the difference between the plum pudding model of the atom and the nuclear model of the atom.
  - Lesson 02 - How do atoms interact with electromagnetic radiation? Lesson Plan Lesson Title
    - Atoms are very small, having a radius of about 1 x 10^-10 metres.
    - The basic structure of an atom is a positively charged nucleus composed of both protons and neutrons surrounded by negatively charged electrons.
      - Suggested Activity:
        Model an atom using plasticine. On the model show where most of the mass in concentrated and that most of the atom is empty space.
        
        Describe the composition of an atom and draw a fully labelled diagram of an atom showing protons and neutrons in the nucleus with electrons outside the nucleus.
        Equipment Required:
        plasticine
    - The radius of a nucleus is less than 1/10,000 of the radius of an atom.
    - Most of the mass of an atom is concentrated in the nucleus.
    - The electrons are arranged at different distances from the nucleus (different energy levels).
    - The electron arrangements may change with the absorption of electromagnetic radiation (move further from the nucleus; a higher energy level) or by the emission of electromagnetic radiation (move closer to the nucleus; a lower energy level)
      - Suggested Activity:
        Use equipment to see how different coloured filters absorb different wavelengths of light
        
        Research how absorption and emission spectra are formed.
        Equipment Required:
        ray boxes
        data loggers with temperature probes
        power packs
        cables
        coloured filters to slot into ray box
  - Lesson 03 - How do subatomic particles relate to each other? Lesson Plan Lesson Title
    - In an atom the number of electrons is equal to the number of protons in the nucleus.
    - Atoms have no overall electrical charge.
    - All atoms of a particular element have the same number of protons. The number of protons in an atom of an element is called its atomic number.
    - The total number of protons and neutrons in an atom is called its mass number.
      - Suggested Activity:
        Calculate the mass number for a particular element given the number of protons and neutrons in the atom. Rearrange the equation to find number of protons or number of neutrons and the mass number.
    - Atoms can be represented as shown in this example:
      (Mass number) (Atomic number) 23 11 Na
      - Suggested Activity:
        Produce a table showing the mass number, atomic number and number of neutrons for an element given in the form (_11^23) Na .
    - Atoms of the same element can have different numbers of neutrons; these atoms are called isotopes of that element.
      - Suggested Activity:
        Use simple modelling techniques to show that the number of protons in an isotope of an element remains constant but the number of neutrons changes.
        Equipment Required:
        Plasticine
        fluffy balls
    - Atoms turn into positive ions if they lose one or more outer electron(s).
      - Suggested Activity:
        Use students to model losing electrons.
    - Students should be able to relate differences between isotopes to differences in conventional representations of their identities, charges and masses.
  - Lesson 04 - What is nuclear radiation? Lesson Plan Lesson Title
    - Some atomic nuclei are unstable.
    - The nucleus gives out radiation as it changes to become more stable. This is a random process called radioactive decay.
    - Activity is the rate at which a source of unstable nuclei decays.
    - Activity is measured in becquerel (Bq)
    - Count-rate is the number of decays recorded each second by a detector (eg Geiger-Muller tube).
    - An alpha particle (α) is this consists of two neutrons and two protons, it is the same as a helium nucleus
      - Suggested Activity:
        Model alpha, beta, gamma and neutron decay using plasticine and/or stop frame animation. Models should show the atom before and after decay as well as the radiation emitted.
        Equipment Required:
        Plasticine
        Cameras
    - A beta particle (β) is a high speed electron ejected from the nucleus as a neutron turns into a proton
    - A gamma ray (γ) is electromagnetic radiation from the nucleus
    - The nuclear radiation emitted may be also be a neutron (n).
    - Alpha is stopped by a few centimeters of air or a sheet of paper.
      - Suggested Activity:
        Demonstrate the penetration of alpha, beta and gamma radiation. Link the penetration of each type of radiation to the nature of the radiation and the uses of the radioactive sources.
        Equipment Required:
        Radioactive sources
        Geiger muller tube
        counter.
    - Beta is stopped by a few millimeters of aluminium
      - Suggested Activity:
        Plan an experiment to determine the type of radiation emitted by an unknown radioactive source. Produce a risk assessment for this experiment.
    - Gamma rays are stopped by a few centimeters of lead or a few meters of concrete.
    - Gamma rays are the least ioninsing, because they are not charged.
    - Alpha particles are the most ioninsing as they have a charge of plus 2.
    - Students should be able to apply their knowledge to the uses of radiation and evaluate the best sources of radiation to use in a given situation.
  - Lesson 05 - How does nuclear radiation change an atom? Lesson Plan Lesson Title
    - Nuclear equations are used to represent radioactive decay. (diagram)
    - In a nuclear equation an alpha particle may be represented by the symbol:The symbol of an alpha particle.
    - The symbol of a beta particle.
    - The emission of the different types of nuclear radiation may cause a change in the mass and /or the charge of the nucleus.
    - alpha decay causes both the mass and charge of the nucleus to decrease.
    - Beta decay does not cause the mass of the nucleus to change but does cause the charge of the nucleus to increase.
    - Students should be able to use the names and symbols of common nuclei and particles to write balanced equations that show single alpha (α) and beta (β) decay. This is limited to balancing the atomic numbers and mass numbers. The identification of daughter elements from such decays is not required.
    - The emission of a gamma ray does not cause the mass or the charge of the nucleus to change.
  - Lesson 06 - What is half life? Lesson Plan Lesson Title
    - Radioactive decay is random.
      - Suggested Activity:
        Model the radioactive decay of alpha and beta sources. Use the model to construct decay equations for alpha and beta decay. Critically analyse the limitations of the models produced by the class.
        
        Demonstrate the randomness of the decay of a radioactive substance by throwing six dice and getting a prediction of the number of dice that will land on a six. Alternatively, drop 20 coins and get students to predict the number that will land on a head.
        Equipment Required:
        Dice
    - The half-life of a radioactive isotope is the time it takes for the number of nuclei of the isotope in a sample to halve, or the time it takes for the count rate (or activity) from a sample containing the isotope to fall to half its initial level.
    - Students should be able to explain the concept of half-life and how it is related to the random nature of radioactive decay
      - Suggested Activity:
        Investigate half-life by throwing a large number of Tillich bricks. Any that land on the side with the odd colour get removed and the number remaining is recorded. Plot a graph of the number of throws against number of cubes remaining. Determine the half-life of the cubes (the number of throws needed to get the number of cubes to reduce by half).
        This experiment can also be carried out using coins. Is it possible to predict which cubes or coins will land on a certain side?
    - Students should be able to determine the half-life of a radioactive isotope from given information.
    - (HT only) Students should be able to calculate the net decline, expressed as a ratio, in a radioactive emission after a given number of half-lives.
  - Lesson 07 - What is radioactive contamination? Lesson Plan Lesson Title
    - Radioactive contamination is the unwanted presence of materials
      containing radioactive atoms on other materials.
      - Suggested Activity:
        Describe how radioactive contamination can occur.
        
        Compare precautions taken by a teacher handling radioactive sources with those used by, say, in a nuclear power station.
    - The hazard from
      contamination is due to the decay of the contaminating atoms. The type of radiation emitted affects the level of hazard.
    - Irradiation is the process of exposing an object to nuclear radiation. The
      irradiated object does not become radioactive.
    - Students should be able to compare the hazards associated with
      contamination and irradiation.
      - Suggested Activity:
        Evaluate the use of irradiating fruit in terms of cost of goods and potential risk due to the exposure of workers and consumers of the irradiation process.
    - Suitable precautions must be taken to protect against any hazard that
      the radioactive source used in the process of irradiation may present.
      - Suggested Activity:
        EW : Justify the use of radioactive sources in school in terms of risk-benefit analysis to the students in the class.
  - Lesson 08 - When does background radiation occur? Lesson Plan Lesson Title
    - Background radiation is around us all of the time.
      - Suggested Activity:
        Pose question: Are people in some areas exposed to more background radiation than others? If so why?
    - Background radiation comes from:
      ? natural sources such as rocks and cosmic rays from space
      ? man-made sources such as the fallout from nuclear weapons testing and nuclear accidents.
      - Suggested Activity:
        Pose question: Are we at risk from background radiation?
        Is this greater or less than other parts of the country and why?
    - The level of background radiation and radiation dose may be affected by occupation and/or location.
    - Radiation dose is measured in sieverts (Sv)
    - 1000 millisieverts (mSv) = 1 sievert (Sv)
    - Students will not need to recall the unit of radiation dose.
    - Nuclear radiations are used in medicine for the:
      ? exploration of internal organs
      ? control or destruction of unwanted tissue.
      - Suggested Activity:
        Research some radioactive sources used in medicine and the properties of these tracers (half-life, type of radiation emitted and state).
        Find out how nuclear radiation can be used in the diagnosis and treatment of cancer.
    - Nuclear radiations are used in medicine for the:
      ? exploration of internal organs
      ? control or destruction of unwanted tissue.
    - Students should be able to describe and evaluate the uses of nuclear radiations for exploration of internal organs, and for control or destruction of unwanted tissue
    - Students should be able to evaluate the perceived risks of using nuclear radiations in relation to given data and consequences.
    - Radioactive isotopes have a very wide range of half-life values
    - Students should be able to explain why the hazards associated with radioactive material differ according to the half-life involved
      - Suggested Activity:
        Pose question: Why can’t radioactive waste be thrown in landfill sites?
  - Lesson 09 - What is the difference between fission and fusion? Lesson Plan Lesson Title
    - Nuclear fission is the splitting of a large and unstable nucleus (eg uranium or plutonium).
    - Spontaneous fission is rare. Usually, for fission to occur the unstable nucleus must first absorb a neutron.
    - The nucleus undergoing fission splits into two smaller nuclei, roughly equal in size, and emits two or three neutrons plus gamma rays. Energy is released by the fission reaction.
      - Suggested Activity:
        Model nuclear fission of a uranium nucleus. Use students.
    - All of the fission products have kinetic energy.
      - Suggested Activity:
        Watch - https://www.youtube.com/watch?v=1U6Nzcv9Vws
        
        Use ideas from Energy topic (4.2) to answer question: Explain how the kinetic energy of the products is transferred to boil water.
    - The neutrons may go on to start a chain reaction.
      - Suggested Activity:
        Model chain reactions using dominos or matches.
    - The chain reaction is controlled in a nuclear reactor to control the energy released.
    - The explosion caused by a nuclear weapon is caused by an uncontrolled chain reaction.
      - Suggested Activity:
        GF : Investigate the causes of the Chernobyl and Fukushima nuclear disasters. Have the lessons of these events been learnt? How can nuclear power be made safer than it is currently?
    - Students should be able to draw/interpret diagrams representing nuclear fission and how a chain reaction may occur.
    - Nuclear fusion is the joining of two light nuclei to form a heavier nucleus.
      - Suggested Activity:
        Write simple word or symbol equations for the fusion of two hydrogen atoms or other light elements.