Deconstructing Changes in the IGCSE Science Syllabus

Written by Tim Lovatt

Tim is a teacher of IBDP Physics and IGCSE sciences at United World College of South East Asia (Dover Campus) in Singapore, where he also works as an instructional coach. He has worked as a consultant and author for Kognity for three years.

18th September 2020

It is easy to think, at first glance, that the new Cambridge IGCSE Science syllabus for Biology, Chemistry and Physics is just a small movement in content from previous years. In many ways, this is true, but there have been significant shifts in some areas which seem to follow a few distinct themes. In order to really understand the changes and translate them into what they might look like in a classroom, we’ve deconstructed them and categorised them wherever possible. Here’s a breakdown. 

 

Biology

image of savanna

Biology is perhaps the least changed of the three sciences, but a significant number of the changes seem to follow a theme of avoiding potentially sensitive topics for individuals, with the removal of hereditary diseases, drug abuse and contraception. A few topics have been reshuffled in the way the syllabus has been presented, but are still present and as such are not listed here.

 

Content Removed

Whilst none of the changes are vast, some may have broader implications than others so they are listed below accordingly.

 

The slightly larger scale changes involve the removal of:

  • The entire section on misuse of drugs and the effects of drugs like heroin on synaptic response
  • Discussion of any malnutrition in humans, with the exception of explicitly named scurvy and rickets
  • A big section of human reproduction, including the growth of the fetus, antenatal care of women, breastfeeding vs. formula, the process of childbirth and the entire section on birth control
  • Acid rain, sulfur dioxide and female contraceptive hormone pollution
  • All content on sickle cell anaemia along with the specific effects of HIV.

 

Smaller scale removed content includes:

  • Describing water as a solvent, and different sequences of amino acids forming different proteins
  • Treatment of coronary heart disease – with prevention being moved from supplement to core
  • Tooth decay and tooth care
  • The lymphatic system
  • The water cycle
  • Recycling and sewage treatment
  • Synthetic hormones in weed killers
  • The term ‘turgor pressure’ from osmosis
  • Nitrate and magnesium deficiency in plants
  • Dialysis
  • The implications of increasing population on food security and famine
  • Effects of oestrogen and testosterone.

 

Content Added

The content that has been added is largely small extensions of existing subtopics and syllabus points and doesn’t involve additions of entire subtopics (unlike Physics, see below). However, the additions are numerous and will need close attention when incorporating into a scheme of work. They include:

  • The structure and features of a bacterial cell
  • Detail on lignin in xylem vessels
  • Explicit naming of ‘air spaces’ in leaf structure
  • Discussion of large, thin leaves being adapted for photosynthesis
  • More depth on some digestive definitions
  • Naming of veins and arteries to and from the liver
  • Wind speed as a transpiration rate factor
  • Mechanism of blood clotting
  • More detail on the production of urea
  • Insulin and mycoprotein fermentation, along with control factors in a fermenter
  • Conservation programs.

 

Content Moved or Changed

Several syllabus points have been moved from supplement to core and there seems to be a little more of a focus on terminology and nomenclature in the small changes that have been made. 

Changes or Alterations

  • Renamed nerve cells as neurones
  • Investigation into the uptake of oxygen for respiration has changed to investigating the dependence of rate of respiration on temperature in yeast (and has also moved from supplement to core)
  • Mitosis and meiosis have been entirely moved to supplement from core, and some details have been changed or removed, such as the outcome of meiosis.

Moved from Supplement to Core

  • The factors affecting diffusion and its source of energy
  • The term ‘active site’ and ‘denaturation’ for enzymes
  • Photosynthesis content:
      • Uses of carbohydrates
      • Use of hydrogencarbonate indicator
      • The role of chlorophyll
      • How leaf cells are adapted for photosynthesis
  • Surface area specialisation of root hair cells
  • Role of blood clotting
  • Comparison of nervous and hormonal control
  • Sperm and egg cell features
  • Temperature regulation in mammals
  • Selective breeding
  • Flow of energy from the sun
  • Identification of some organisms from food pyramids
  • Ecosystems, communities and limited-resource population growth curves
  • Effects of deforestation
  • Effects of non-biodegradable plastics.

 

Chemistry

Chemistry lab

The chemistry syllabus has undergone the largest change in terms of its layout and categorisation of subtopics. There has been a big shuffle in how the content is laid out, but a lot of it has been moved around and there are only (relatively) minor additions and subtractions.

Content Removed

Two entire subtopics have been removed, and whilst some of the content has been reassigned to other subtopics, some has been removed completely:

  • The subtopic “Carbonates”, although some of the content has been moved to other subtopics.
  • The subtopic “Sulfur”. Whilst some content has been moved to other subtopics, sulfur sources and uses of sulfur dioxide have been removed entirely
  • Carbon cycle
  • Carbohydrates and hydrolysis of carbohydrates
  • Radioactive isotopes as energy sources
  • The impact of acidity on soil
  • Brownian motion
  • Conversion of iron into steel, and uses of steel
  • Uses of noble gases
  • Silver salts in photography.

Content Added

Significant changes include the addition of acid-base titrations and thymolphthalein indicator, but the list is longer than that. It includes:

  • The explanation of pressure in a gas and interpretation of heating/cooling curves
  • “Reaction pathway diagrams” for endo and exothermic reactions
  • Oxidation numbers
  • The environmental impact of plastics
  • Comparison between gasoline and H-O fuel cells along with more detail on fuel cells
  • Advantages and disadvantages of measuring techniques
  • Electrolysis of Hydrochloric Acid
  • Acid-base titrations
  • The terminology “enthalpy change” as the transfer of thermal energy
  • Thymolphtalein indicator added to acids and bases
  • The term “water of crystallisation”
  • Reactions of metals with water and steam
  • The flame test for barium
  • A more in depth discussion of the reaction between alkanes and chlorine
  • The idea of equilibrium and net reaction direction for reversible reactions
  • A much more in depth discussion on impurities in water and testing for purity by measuring melting point and boiling point
  • Pressure of gases as a factor affecting rate of reaction
  • More detail on the properties of the fractions of crude oil
  • Carbon dioxide and methane as air pollutants
  • Knowledge of photosynthesis and preventative measures to control climate change and acid rain
  • Much more explicit detail in the contact and haber processes, along with economic and safety considerations.

 

Content Moved

Several syllabus points have been reshuffled from supplement to core, or vice versa, including:

  • The deduction of formula from diagrams moved from core to supplement
  • H and OH ions as influencers of pH moved from supplement to core
  • Explanation of periodic trends moved from supplement to core.

 

 

Physics

Solar Panels

The Physics syllabus has changed in perhaps the most fundamental way of all three sciences. It has seen some long-awaited changes involving the removal of some old fashioned measurements and calculations such as thermal capacity and manometers, and the addition of an entire topic which goes into a lot of depth on so-called “Space Physics”.

 

Content Removed

Significant amounts of removed content have paved the way for the addition of the new topic, including:

  • Digital electronics and logic gates
  • The measurement of temperature and thermometer design
  • Thermal capacity 
  • Latent heat of vaporisation and fusion, and associated calculations
  • Measurements and calculations using micrometers, barometers and manometers
  • Typical values of the speed of sound in solids and liquids
  • Methods of demagnetisation and magnetisation
  • Charging by induction.

 

Content Added 

By far the biggest addition to this edition of the syllabus is the addition of the “Space Physics” topic. It is broad-ranging in scope and has remarkable depth for a new addition to the syllabus. The content added includes:

  • Space Physics – including planets, solar system, orbits and orbital speed calculations, life cycles of stars, the light-year, CMBR, red-shift, and the hubble constant for finding distance based on redshift and for finding the age of the universe
  • The absolute scale of temperature (Kelvin) and conversion from K to C
  • Use of the kilowatt-hour unit
  • Idea of thermal equilibrium added in terms of radiation emitted and absorbed, particularly with regards to the Earth
  • Calculation of resultant vectors mathematically
  • g is now explicitly stated as 9.8
  • Thin diverging lenses
  • Prediction of liquids floating on each other given their densities
  • Proportionalities of circular motion, but not the equation
  • Sankey diagrams
  • Nuclear fusion prospects
  • Harmful effects of EM waves expanded to include burns from IR and cancer from UV
  • Discussion of digital vs analogue signal 
  • The use of microwaves by wifi and bluetooth, and the reasons microwaves are used
  • Density of magnetic field lines to represent field strength
  • Different definitions for PD and emf, and equations: V=W/Q and emf, E = W/Q
  • Potential dividers given more explicit descriptions and an equation
  • Use P=I2R to explain why transformers are needed for transmission
  • Origins of radioactivity in terms of neutron number or mass and the subsequent stabilisation following decay
  • Explain the safety precautions for handling radioactive samples

 

Content Moved

Consistent with the other two sciences, some content has been reassigned to core from supplement, including several equations:

  • Velocity vs speed moved from supplement to core
  • Work done and power equations moved from supplement to core
  • Wave speed equation moved from supplement to core
  • Virtual nature of reflections moved to core
  • P=IV and E=IVt moved from supplement to core.

 

Important Note

While we’ve dug into the changes in some depth here, it is still necessary for teachers or programme leaders to read the new syllabus in full before planning any units of work.

Final Thoughts

In the larger context, the changes to the science curriculum have been minor and will likely not result in any huge upheaval of schemes of work. The general pattern of updating and modernising shows an attempt at making the syllabus more relevant to the modern world. 

 

Needless to say, here at Kognity we’re already working hard to produce the updated version of our IGCSE Science textbooks which will be ready for students to access as soon as the 2023 cohort begins their study. We’re excited to share the journey with you.

Do you want to stay in touch regarding our updated IGCSE Science Books?

 

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