Aerobic and anaerobic respiration
The resources in this list help students to explore the relationships between food molecules as a source of energy, cellular respiration and physical or cellular activity. Respiration is a difficult concept for students as it cannot be directly observed. However, by creating opportunities for students to collect and discuss a range of evidence they can determine a word equation for respiration and construct their own understanding of the process.
From 2014, students should learn about:
• aerobic and anaerobic respiration in living organisms, including the breakdown of organic molecules to enable all the other chemical processes necessary for life
• a word summary for aerobic respiration
• the process of anaerobic respiration in humans and micro-organisms, including fermentation, and a word summary for anaerobic respiration
• the differences between aerobic and anaerobic respiration in terms of the reactants, the products formed and the implications for the organism.
Visit the secondary science webpage to access all lists: https://www.stem.org.uk/secondary-science
Whilst this list provides a source of information and ideas for experimental work, it is important to note that recommendations can date very quickly. Do NOT follow suggestions which conflict with current advice from CLEAPSS, SSERC or recent safety guides. eLibrary users are responsible for ensuring that any activity, including practical work, which they carry out is consistent with current regulations related to Health and Safety and that they carry an appropriate risk assessment. Further information is provided in our Health and Safety guidance.
Breathing and Circulation
A classic misconception is that breathing and respiration are the same process and students often fail to connect the intake of oxygen through breathing with the chemical process of respiration which releases energy in cells. This needs to be addressed from the outset.
Students can see evidence that they breathe out carbon dioxide by carefully blowing down a straw into a beaker of clear limewater and noting the colour change.
Although this book looks dated, there is a good diagram on page 3 showing how to extend this simple test further so that students can compare the air they breathe in with the air they breathe out.
This can be followed by measuring breathing rates before and after exercise. After counting the number of breaths at rest for one minute, ask students to perform an exercise for one minute and then count their breaths again for one minute. After resting for three minutes, the process can be repeated but this time they exercise for two minutes. Did their breathing become deeper? What other changes did they notice? This can help students to make the link between breathing and cellular respiration.
Further on in the book there are some ideas for practical activities which can be used to introduce the idea of anaerobic respiration in later lessons.
Screaming Jelly Babies
This is a dramatic and memorable demonstration of what happens if you release all the energy stored in food (a jelly baby) at once! It provides a good introduction to cellular respiration, by which the energy in glucose is released inside our cells by a series of carefully controlled reactions designed to ensure that only small, collectable amounts of energy are released at any one time.
As always, carry out your own full risk assessment before attempting any demonstration, as advice from CLEAPSS on the use of fume cupboards for this demo has changed.
The similarities between combustion and cellular respiration
The use of analogies can help students to visualise abstract concepts such as respiration. This is an interesting article about the similarities between combustion in an engine and cellular respiration. The idea could be adapted to provide a useful assessment activity or homework by asking students to produce their own comparison of the two processes. The task can be differentiated by providing key words which the students should include (such as fossil fuels, sugar, piston, muscle) and a writing frame to scaffold the comparison.
Useful Microbes for Secondary Science
This e-Bug resource contains teacher guidance, stimulus materials and student activity suggestions. It looks at useful microbes by examining the various ways and means we can utilise them for our benefit.
