In this blog I will evaluate how I taught a successful lesson, covering what are the basic components of blood, Blood vessels, and the Heart structure and function. The lesson was aimed at Year 9 students, who are preparing for the GCSE Trilogy (9-1) Combined Science course.
Students were mixed ability, mixed gender, aiming at grades 1-3 Eleven out of twenty-five have low-level dyslexia, two have mild AHDH. Evidence from testing indicates that all students were able to achieve a grade 5. (2- hours required)
The objectives were:
- To simply consider what is in the blood and what the blood does.
- To compare arteries, veins, and capillaries in terms of the size of the lumen, the pressure of blood flowing through the vessel and the function of the blood vessel.
- To appreciate why a heart is needed and describe the major parts of the heart using a labeled diagram.
To connect together arteries, veins, and capillaries with the heart, lungs and rest of the body.
Activities carried out were:
A clear starter: An empty diagram of the heart to label, using starter letters as prompts. A keywords mat, colour coding the passage of oxygenated blood and deoxygenated blood using red and blue.
Activity 1: Using tubing of various sizes to 'model' the arteries, veins, and capillaries attached to a clamp stand students had to investigate how to long takes for blood to travel through the blood vessels. (Fake blood made up with red washing up liquid mixed with red food dye and ethanol drops to stop frothing; to give the illusion of real gluepy blood). It was delivered as an investigation, with prior questions on Independent, Dependent and Control Variables.
Independent- Thickness of blood vessel
Dependent- Time taken for blood to travel through the blood vessels (rubber tubing of various thicknesses). (seconds)
Control- The length of the rubber tubing/ distance on clamp stand/ volume of fake blood used measured with a pipette at 2.5cm3.
Caution was taken to avoid spillages, wear safety goggles and use a 250ml beaker to 'catch the blood' at the end. All loose hair was tied back. Students wore lab coats and sensible conduct was established.
Avoid blood spillages)
Students recorded their results in a results table that they constructed themselves and were amended as advised. At this stage, many students were writing in 'seconds' multiple times in their results table. This had to be corrected. Students had to draw a bar chart of the thickness of lumen versus time taken for blood to travel. Some students used qualitative categorization, whereas others measured the diameter of the lumen in mm with a ruler. They then displayed their bar-charts to each other and applied post-it notes to indicate if their results were similar to others. The results were evaluated.
Students related their results in comparison to the blood vessels. The capillaries seemed to allow blood to flow easily but the slowed was the thickest rubber tube (arteries). So from questioning, students deduced that the blood flow through the arteries needed a pump. They discovered which parts of the heart prevented backflow within the heart. I asked students the following questions:
1. What would happen if the arteries became clogged with fat?
2. Why are arteries so thick? What would happen if they were thin but under pressure from the heart? What effect would this have on the rest of the body?
3. How do we stop backflow of blood in the heart?
4. What sort of blood goes through the arteries? Where does it go?
5. Why do the veins not have thick walls?
I told the students honestly why we had to use fake blood and told them what was in it. They seemed relieved to know that they were not risking their lives to catch a disease. Students were asked in groups to brainstorm what was in real blood:
They could all tell me the following without input:
Red blood cells, white blood cells, sugars, water and something to clot the blood. They also told me it carried oxygen.
From the answers on a powerpoint, they added some extras: Platelets and plasma, carbon dioxide and the types of white blood cells ( B & T lymphocytes, Killer cells, Neutrophils.. etc), ionic salts and glucose.
We discussed the purpose of these. Students were given a handout with diagrams of these and were asked to write their own 3 questions and test each other from the facts.
Activity 4: The circulatory game
Students were given a diagram of the circulatory system together with cutouts of biconcave red blood cells and O2/CO2 particles stuck on with blue tack. Students had to demonstrate the correct path of oxygenated blood, 'drop off' oxygen and 'pick up' carbon dioxide. They used a dice to take turns in pairs. The student with the most amount of oxygen transported through the body was the winner. There was a time limit of 12 minutes imposed on this activity and then students had to swap partners.
Activity 5: Students had to write a Tweet or a Facebook post on what they had learned so far...
Activity 6: Application of Knowledge.. Exam question practice.
(3 questions used from each grade range). This was an open book activity. Students marked their own questions from the answers given on the board, self-evaluated and improved their answers. Again the students were given word mats to help them structure their answers. Scaffolding and correcting were permitted.
Activity 7: Video from Youtube titled: The circulatory system (The heart rap), followed by karaoke to make the key facts stick on a subconscious level. (...Next lesson: Heart dissection/ making a model heart).
The double lesson worked on three levels.
1. The students were motivated and enthusiastic about being in the lesson. I had worked on building a good relationship with these students for weeks. This meant that there was mutual trust between us.
2. The students are hands-on kinesthetic learners and enjoyed the practical aspect of relating to the concepts and ideas.
3. Learning didn't feel like a chore but a gateway of discovery and play. Even though there were exam questions to practice, there was a competitive element to the lesson and a need to impress me as well as each other. Students knew that they would have the opportunities to improve in a non-threatening pleasant environment.
I hope you enjoyed this blog........ Sheila Emery (Science Teacher)
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