Biology / human biology and science teachers

[sashh]

What is happening with the teaching of circulation?

I'm a supply teacher in FE, I teach health and social care which includes anatomy and physiology.

In the last academic year I have taught in FE colleges in various parts of the country and I am increasingly having to teach that blood is not blue.

Every time I start with another class I'm told, "blood is blue until it comes in to contact with air, then it turns red".

It's not everyone in the class, but between 1/3 and 1/2.

Are students being taught deoxygenated blood is blue on the diagrams to pass GCSE and some don't take on board the 'to pass' bit? If that is the case I can understand it, but I keep having students tell me I am wrong, and offering explanations about blood changing colour 'when it mixes with air' which is why 'when you cut yourself you bleed red'.

Also arteries and veins. I teach that arteries take blood from the heart and veins return it to the heart, blood from the left ventricle goes tot he coronary arteries and the body, blood from the right ventricle goes to the lungs.

I have been asked by students taking science GCSE why there is a different answer for Science, and I don't know.

Does the GCSE syllabus need students to identify arterial blood as oxygenated?

All the diagrams in the textbooks have red for oxygenated blood and blue for deoxygenated blood. That's probably where the misconception that deoxygenated blood is blue comes from (and the very visible veins on the inside of your wrist look blue). The exams are in black and white so it wouldn't be any help for them to look for blue on the diagrams to identify where the blood is deoxygenated.

In my experience most students doing health and social care are on the lower end of the ability range so that's probably why you're seeing this problem so much. They are definitely required to know that blood in arteries is oxygenated and blood in veins is deoxygenated. The colour of blood is not explicitly mentioned and I've never come across the "blue blood turns red when it comes out of the body because it comes into contact with air" misconception which is actually quite a nice wrong explanation! They often remember it correctly for a while and then forget what they've been taught so what you're seeing is probably their vague recollections from a year ago when they were sitting their GCSEs so the details have got muddled.

Just keep telling them that whether they're in science or anywhere else blood is red (maybe gloss over the fact that deoxygenated is a different shade of red).

blue blood turns red when it comes out of the body because it comes into contact with air" misconception which is actually quite a nice wrong explanation!

Tell me about it! And yes I have had wrists proffered to show me I'm wrong.

And I could understand one class from one school getting it wrong but this has happened in colleges literally hundreds of miles apart.

They are definitely required to know that blood in arteries is oxygenated and blood in veins is deoxygenated.

But that's wrong. Pulmonary arteries take deoxygenated blood to the lungs to be oxygenated and pulmonary veins return oxygenated blood to the left ventricle.

I make no wonder they get confused.

Oh and thank you

I would suspect that a lot of students taking Heath and Social Care didn't do Biology GCSE, but did Core and Additional Science. I teach AQA, and circulation doesn't appear in Core and Additional, only in B3 which is the extra unit for Biology GCSE. So they were taught it in KS3, and have forgotten it/had years of common misconception reinforced since.

I suspect that several years down the line, they will have imperfect recall of everything they are learning now.

Sorry I was typing while watching the TV and was half distracted. I do teach them properly about arteries and veins! They are required to know where in the body the blood becomes oxygenated (ie the lungs) and that arteries take blood away from the heart while veins take blood towards the heart. They have to know whether blood in a particular vessel is oxygenated or deoxygenated. You can look at the wording of the syllabus on any of the exam board websites.

I think FallenMadonna and purple are probably right.

I'm sure plenty of children leave ks2 with misconceptions about stuff that has been taught correctly. leaving their ks3 teachers complaining about what's being taught in primary.

IIRC, ASE used to do a section on common misconceptions. I wouldn't be at all surprised if this one was in there.

There is a bit of simplification in the earlier years too. Also lots of teaching by non specialists.

If I got a fresh group of GCSE students who all said arteries carried oxygenated blood and veins carried deoxygenated blood I'd be over the moon because that's only a little misunderstanding to correct and they've got the basic knowledge there. How they think hormones get around the body is another matter entirely.

Why do blood vessels in the wrist look blue then?

Maybe TMI?

It is complicated teen! The simple answer is it is to do with how light is absorbed and reflected off your skin, and how your brain interprets the information that comes from your eyes when the light gets to them.

I can't find a simple web page but this one is quite nice...
osuwomeninphysics.wordpress.com/2015/03/11/everyday-physics-why-do-veins-look-blue/

Cross posted with you madonna.

I used to teach secondary science, and I have had a few students absolutely refuse to believe me when I say that blood is not blue. One just grimaced and shook her head, insisting that "no, no, no" and that "a doctor" had told her it was blue.

Drove me spare.

When I did my O level I was told "ignore everything you learned before - it was wrong and simplified"

When I did my A level I was told "ignore everything you learned before - it was simplified and thus wrong"

When I did my degree I was told "ignore everything you learned before - it was a simplification of the reality"

Some things never change

You shouldn't have to ignore what you learned before. Just add to it. I rather like giving GCSE students a tantalising glimpse of what respiration looks like at A level. And A level students a peek at an undergraduate text.

TeaStory

So maybe it is something from primary?

TeenAndTween

Oxygenated blood, fresh from the lungs is a very bright red, as the oxygen is used up it becomes darker, the red blood cells that carry the oxygen are still red but have less oxygen so are a dark crimson. If you have ever donated blood or been given blood in hospital this is the colour of the blood in the bag.

In a previous life I have worked in a cath lab where a cardiologist would hand me samples of blood from different parts of the heart, it's amazing, and beautiful to have 20 samples all of slightly different shades of red.

Anyway the blood in the veins is red but a combination of the colour of vein walls and the colour of flesh make them appear blue.

Oh and lobsters and some crabs have blue blood.

I don't think this is from primary. I don't think that oxygenated/de-oxygenated blood was on the KS2 curriculum.

Tea, I once had a child who was convinced that sand was a liquid because her mum had told her so. Absolutely nothing I did or said made any difference. It was a very frustrating half term.

I am quite an educated adult, although didn't study science pass GCSEs, and I did think this was a fact of life. I think somehow this is something that has reached the normal population belief, just like antibiotics will cure a sore throat, with all the campaign needed to be put in place to outdo that wrong belief.

I would have argued that blood was blue inside the body, so glad I've learnt something interesting today (and will definitely question DD about it who wants to go on study medicine!).