Biology Practicals

This page is undergoing a long overdue update 
The key practical activities which are specified in the Biology IGCSE syllabuses, are mostly things which you can do at home without too much difficulty. On this page you will find lists of key practical activities, some comments on doing them from home-ed, and information on where to find supplies, instructions, and equipment.
==Edexcel International GCSE==
Practicals in bold are only required for 4BI1 Biology, not 4DS0 Science (Double Award)
Specification Reference 	Notes 	Video Links
2.9  -  Investigate  food samples  for  the  presence of  glucose,  starch,  protein and  fat 	Kitchen Chemistry on Ebay sells a kit that tests for starch and sugars
1. Identify  starch  by  using  potassium  iodide solution 
2. Identify  reducing  sugars  using  Benedict’s solution  (and  a  water  bath) 
3. Identify  protein  using  the  Biuret  test  (adding potassium  hydroxide  to  a  solution  of  the food,  followed  by  copper  sulfate) 
4. Identify  fats  and  oils  (lipids)  using  the emulsion  test  to  show  the  formation  of  a precipitate	Malmesbury Education - Food Tests - GCSE required practical
Pearson UK Educators - Testing for starch, reducing sugars, proteins and fats
2.12  -  Investigate  how enzyme  activity  can  be affected  by  changes in temperature 	The Nuffield Foundation has a lesson plan which is easy to do at home. 	Mr Riddz Science - How Temperature affects enzyme activity.
2.14B  -  Investigate  how enzyme  activity  can  be affected  by  changes  in pH 	Another lesson from the Nuffield Foundation which is doable at home. Kitchen Chemistry on Ebay is good for supplies.	Malmesbury Education - Enzymes - required GCSE practical
Pearson UK Educators - pH and enzymes
2.17 - Investigate diffusion and osmosis using living and non-living systems 	 	Malmesbury Education - Osmosis -GCSE Science Required Practical
Pearson UK Educators - Osmosis in potatoes
2.23 - Investigate photosynthesis, showing the evolution of oxygen from a water plant, the production of starch and the requirements of light, carbon dioxide and chlorophyll	 	
Mr Exham - photosynthesis experiments (screen-based overview of the starch leaf and pondweed experiments)
Malmesbury Education - Rates of Photosynthesis - GCSE Science Required Practical (water plant)
teachingbioproject - Co2 is necessary for photosynthesis
Tom Dare - testing a leaf for starch for IGCSE biology
Teachingbioproject - Chlorophyll is necessary for photosynthesis
2.33B - Investigate the energy content in a food sample 	 	The Science Break - Edexcel GCSE Biology - Calorimetry (screen-based explanation of experiment)
2.39 - Investigate the evolution of carbon dioxide and heat from respiring seeds or other suitable living organisms 	 	Mr Exham - Respiration Experiments - GCSE (9-1) 
(screen based overview of experiments)
2.45B - Investigate the effect of light on net gas exchange from a leaf, using hydrogen- carbonate indicator 	 	
2.50 - Investigate breathing in humans, including the release of carbon dioxide and the effect of exercise 	 	
2.58B - Investigate the role of environmental factors in determining the rate of transpiration from a leafy shoot 	 	
3.5 - Investigate the conditions needed for seed germination 	 	
4.2 - Investigate the population size of an organism in two different areas using quadrats 	 	Pearson UK Educators - Fieldwork Techniques
4.4B - Investigate the distribution of organisms in their habitats and measure biodiversity using quadrat 	 	Pearson UK Educators - Fieldwork Techniques
5.6 - Investigate the role of anaerobic respiration by yeast in different conditions 	 	Pearson UK Educators - rate of respiration
=== New GCSE syllabus for exams from 2018 ===
 
The IGCSE biology syllabuses also refer to key practicals and the Edexcel teacher's guide lists 15 that are recommended. 
==== 1. Investigate the factors that affect enzyme activity ====
http://www.nuffieldfoundation.org/practical-biology/factors-affecting-enzyme-activity
Various activities which are easy to do at home.
==== 2. Investigate the use of chemical reagents to identify starch, reducing sugars, proteins and fats ====
Do-able at home.  Can make your own Benedict’s Reagent or buy ready-made.  Food tests kit from Kitchen Chemistry on eBay includes Benedict’s Reagent plus iodine solution.Bio Topics: how to do the four basic food tests.
Mr Rothery’s Biology Site has a fairly technical document  which tells you how to make up food test reagents you might need, if you can’t find them ready-made.
==== 3. Investigate osmosis in potatoes ====
This is very easy to do at home as long as you’ve found a good balance. If you don't have a good balance then you could scale up the size of your potato pieces until you get a result which is big enough for your balance to register.
Investigating the effect of concentration of blackcurrant squash on osmosis chipped potatoes
This activity on observing osmosis in plant cells with a microscope is nice to do at home too: 
http://www.nuffieldfoundation.org/practical-biology/observing-osmosis-plasmolysis-and-turgor-plant-cells
==== 4. Investigate how to extract DNA from fruits ====
All you need for this is some kiwi fruit, pineapple juice, washing up liquid, and surgical spirit! http://thenode.biologists.com/wp-content/uploads/2013/12/Outreach-activity-DNA-extraction-from-kiwi-fruit.pdf
More notes and similar activities from Nuffield Practical Biology:
http://www.nuffieldfoundation.org/practical-biology/extracting-dna-living-things
'''
==== 5. Investigate the effects of antiseptics or antibiotics or plant extracts on microbial cultures ====
Good fun to do at home. There are full instructions for this activity on Nuffield Practical Biology - 'Investigating Anti-microbial action'. 
It may help to work up to using bacteria by doing a simpler practical such as 'Microbes ate my homework!', which investigates the action of microorganisms on paper and doesn't require any special equipment - it can all be improvised.
'Microbes all around us' is a nice investigation of microbes found in the environment. You swab surfaces or hands and see what grows on agar plates. We did this before investigating antibacterial action, but it's not one of the core practicals.
The full investigation of antibacterials on cultures can be done at home. We found it really interesting once we'd become confident working with agar. For a quick result, you can buy ready-made petri dishes containing nutrient agar, ready to use. These are usually easy to find on Amazon and eBay, and Blades Biological sell cultures, agar etc . Food-grade agar is cheaper than laboratory grade and works just as well if you want to make up your own plates - a 100g pot costs about £5 on eBay. A pressure cooker works as a home autoclave; the book on home biology by Robert Bruce Thompson is very useful for this, and for explaining how to do most biology practicals at GCSE level with improvised equipment.
If you are making up your own 'nutrient agar' or 'nutrient broth' to grow microbes, all you need are simple ingredients. Instructions for schools are on the Nuffield site - nutrient agars, but here is what we did:
Nutrient broth: We used chicken stock made up to half the usual strength, plus 1tsp sugar per 100ml. 
Nutrient agar: to 100ml of nutrient broth, add 2g agar. Measurements don't need to be exact; you just need the agar to be a firm constituency. The fine culinary agar powder we used weighed approx 3g per 5ml level teaspoon.
==== 6. Investigate the effect of light intensity on the rate of photosynthesis ====
Very easy to do at home.  Cabomba works better than Elodea:
http://www.nuffieldfoundation.org/practical-biology/investigating-factors-affecting-rate-photosynthesis
Video demonstration: Photosynthesis and respiration with Cabomba pondweed - helpful video showing how to set up and with various suggestions for getting the most out of this activity.
'''
==== 7. Investigate the rate of respiration in living organisms ====
I think of this practical as ‘Plant v Snail’ . We found it straightforward to do at home, and good fun. http://www.nuffieldfoundation.org/practical-biology/how-do-plants-and-animals-change-environment-around-them 
You can buy hydrogen carbonate indicator on ebay, and pondweed, eg Cabomba, from aquarium shops. They will probably let you have some pond snails too.
==== 8. Investigate the relationship between organisms and their environment using field work techniques including quadrats and belt transects ====
This is easy to do from home. First read SAPS guide to using quadrats : http://www.saps.org.uk/secondary/teaching-resources/260-questions-about-quadrats
Video on using quadrats: https://www.youtube.com/watch?v=KuG-UjpQzm0
Then you could do the SAPS Ecology Practical 2: Distribution of species across a footpath - Easily do-able from home-ed, and uses quadrats and transects.  Bingo.
See also Doc Brown’s GCSE Biology guide to population sampling using quadrats: http://www.docbrown.info/page20/AQAscibio24.htm
===== From the Edexcel Teacher’s Guide to the 2011 Biology IGCSE syllabus: =====
“ The use of quadrats to estimate the population size of an organism in two different areas Quadrats can be used to sample part of each area. Calculation will be needed to work out the estimated population size. For example, if 10 quadrats have been used and the total area amounts to 100 quadrats, the estimated population size will be the number of organisms counted in the 10 sample quadrats multiplied by 10. Students are expected to understand the importance of placing the sample quadrats randomly. An interesting way to practise the technique is to throw plastic beads on the floor of the classroom and ask students to guess how many beads there are. The quadrat sampling procedure can be used in front of students to get an estimate. The beads can then be collected and counted. The actual number can be compared to the estimated number and used to see how accurate the estimation was. “
BBC Bitesize Fieldwork Techniques: http://www.bbc.co.uk/schools/gcsebitesize/science/add_edexcel/organism_energy/fieldworkrev1.shtml
=== Instructions for doing practicals ===
Don't be daunted; there is lots of help out there. Nuffield Practical Biology provides teacher instruction sheets and student information on any practical activity you will find on the KS3,4 or 5 syllabus. The site can be hard to navigate and the search function doesn’t work very well, but see the list of Published Experiments and Standard Techniques to track down what you need. See the list of practicals below for more detailed links.
It’s usually helpful to look up the practical on YouTube before carrying it out, as often there will be hints and tips which aren’t mentioned in written descriptions, and you can see what sort of colour change or results you might get. 
Searching for key terms from the experiment plus "home education" or "home school science" often brings up blog articles from other home educators explaining how they did it. 
Feel free to ask questions on the HE Exams Yahoogroup or facebook group, or the Science for Home Education facebook group. Other home educators are usually very happy to share their experiences. 
== Where can I get supplies? ==
Many things you might need can be found on eBay or Amazon.  In addition, some big school suppliers are also happy to sell small orders to home users.  Sometimes you can find nice kits at a reasonable price, which could be sold on to other home educators when you’ve finished.
EduLab, Philip Harris and RapidOnline are popular with home educators. RapidOnline is usually cheapest but the site can be hard to search, so try using Google on its site if you don't find what you want. Philip Harris and EduLab have perhaps a wider range, so are definitely worth trying if you can't find what you want. 
EduLab Microscience Workstation , recommended by one home-edder for basic equipment to cover most biology and chemistry practicals.
Blades Biological  sell preserved specimens and bacterial cultures, agar etc.
Kitchen Chemistry on eBay, supply small quantities of many things you might want, eg a kit for testing food for starch and reducing sugars for £12.99 . Kitchen Chemistry supplies the equipment for home-ed science courses offered by Sam Martell (Echo Education) and has put together a kit of equipment for IGCSE biology. Brian, the owner, doesn't have a website but sells through ebay under the shop name Kitchen Chemistry. He can be contacted on kitchenchemistry@btinternet.com
Sci-Mart are apparently happy to make up packs for home educators and to sell small quantities.
Visking Tubing (Dialysis tubing) for diffusion and osmosis experiments can be bought in 5m quantities from Philip Harris (www.philipharris.co.uk)
=== Balance ===
A 'balance' is just laboratory-speak for scales, but ordinary kitchen scales are not accurate enough to do many of the activities on the chemistry syllabus, and some biology practicals require them - though it's not essential. You can scale up the experiment if you can't get a good balance - eg for the practical on demonstrating osmosis in potatoes, you could use larger pieces of potato so that the overall change in mass is greater.
If you're going to buy a new balance, preferably get one which will weigh in increments of 0.1g for biology. If you can get one going up to 0.01g this is good for IGCSE-level chemistry too. 
A 'jeweller's scale' can be bought for under £10 and, according to this RSC Chemistry teachers' forum discussion, is robust enough for classroom use. 
A larger option is the My Weigh iBalance 201 which costs around £70 - eg http://www.ourweigh.co.uk/table-top-scales/ibalance-201.html . 
Rapidonline are brilliant for cheap equipment and have various robust-looking balances aimed at schools which weigh in intervals of 0.1g for around £35 + VAT. 
The full range is at http://www.rapidonline.com/pocket-portable-balances , then click 'parametric search' to make sense of it all.  Rapidonline are brilliant for value and speed and service, but their website isn't the most user-friendly.
There are also a range of higher quality balances from a company called Radwag, these are made in Europe and can be bought from https://www.scalesmart.com/laboratory-balances there are models from 1 decimal through to ultra micro balances that can measure to 7 decimal places! 
=== Microscopes ===
One member of the HE Exams Yahoogroup wrote:
My tips would be:
1.  If you can buy it in a high street shop then unless you happen to have a specialist shop on your high street, it's probably not much good  :-(  Unless Lidl are doing their annual microscope promotion, in which case it's good value - but you can get the same microscopes online for just a little bit more if it's not that time of year.  I have a couple of high-street £30 'microscope sets' which promised over 1,000x magnification, and actually the image quality was so poor they were not much use - but the slides etc which came with the kits were useful.
2.  A mechanical stage makes a huge difference if you want to look at small things like microscopic organisms and cells, eg cheek cells.  This means that the slide is held in place on a deck and then you turn knobs to move it by tiny increments.  The alternative is to have just clips which hold the slide in place.  This is OK for looking at larger things but it's really frustrating if you're trying to move the slide when looking for  etc, because you move the slide slightly with your hand and your whole landscape changes.  Like suddenly teleporting from London to Reading and missing all the interesting stuff in Slough :-)
3. I think it's sensible not to over-complicate things.  More magnification is not necessarily better as it's very hard to use a microscope at high magnification, because you can't even find what you want to look at!  That's why you start on the lowest magnification and move up step by step.  Don't be dazzled by headline figures about 1250x magnification - the limiting factor is often the quality of the lenses, so you might only get a fuzzy image with a high magnification cheap microscope, and it might be a lot less frustrating to have lower magnification and clearer image.
4.  Learn how to use it properly.  This makes all the difference in the world. See below for books which teach you.
==
My new microscope is the Apex Practitioner and it cost £112, but it's really good and feels like a 'professional' bit of kit, and more robust than the Lidl one which, sadly, my youngest got hold of and damaged :-( Here's the ApexPractitioner: http://www.apexmicroscopes.co.uk/apexpractitioner.html
The Bresser Biolux has been great for us.  I bought it at Lidl for about £50 5 years ago, but of course they don't have it all year round. Lidl also tend to move on to a lower spec model but keep their prices the same. 
Biolux NV 20x-1280x Microscope https://www.amazon.co.uk/dp/B001NL9UNS/
I'm very fond of it, 5 years on, but unfortunately my youngest appears to have made two of the lenses unuseable. You have to be gentle with the mechanical stage - the controls broke on mine early on, but it was easy to superglue back together. 
http://www.amazon.co.uk/gp/aw/d/B001NL9UNS/ref=pd_aw_sim_ph_1?pi=SL500_SR63%2C115&refRID=133QHSWT8FS0EC6ZD5EX
We have the Natural History Museum microscope too, but it's no good for looking at cells etc - it's a good field scope though, for looking at insects etc.  It is not very strong, and unfortunately the LED in ours broke after a very slight tumble, and it's not replaceable.
Microscopy UK is a microscope hobbyist site.  They have a guide to buying a microscope, at:
http://www.microscopy-uk.org.uk/dww/novice/choice.htm
What made all the difference to me was learning to use my microscope properly. 
On the advice of the helpful person on the phone at Brunel Microscopes, I bought this book from them, which is aimed at capable children but was very useful to me as an adult in teaching me how to use the microscope: The Ultimate Guide to your Microscope, by Shar Levine and Leslie Johnstone. You can see it here, alongside lots of other interesting-looking books and booklets: 
http://www.brunelmicroscopes.co.uk/books.html and 
http://www.amazon.co.uk/Ultimate-Guide-Your-Microscope/dp/1402743297/
A new book which is aimed at home hobbyists and US-based high-school home-educators is Illustrated Guide to Home Biology Experiments by Robert Bruce Thompson and Barbara Fritchman Thompson - http://www.amazon.co.uk/Illustrated-Guide-Home-Biology-Experiments/dp/1449396593 .  This is a great book and has lots of detail on what to look for in a microscope,and teaches you how to use it very thoroughly.  I strongly recommend it, but the downside is that it's so detailed that it can seem a bit daunting.  The Levine and Johnstone book is a lot more approachable - the tone is very simplistic as it's aimed at kids, but actually it's a useful book.  Having both is good :-)
There is a very detailed guide to using a microscope properly - the Microscopy Primer on Microscopy UK at http://www.microscopy-uk.org.uk/index.html?http://www.microscopy-uk.org.uk/primer/index.htm (I know the URL looks weird !) .  This is also very technical, and very thorough.
At our home-ed science group, we taught the kids basics of microscope use - I don't recall ever doing this in school,  but everyone, from 7 year olds to 16 year olds, learned things like whether to use top or bottom illumination, finding the subject at the lowest magnification first, how not to smash the slide into the stage, and how to use the mechanical stage to make fine adjustments.  
== More Resources ==
Overview of key Biology practicals for Edexcel IGCSE - table compiled by Tracey S including links etc.
Category:Sciences