Blood — The Lesson I Haven't Solved Yet
Using a dependable blood reading as the baseline while deliberately piloting more active ways to teach composition, transport, structure, function, and healing.
|
THE BIG IDEA This chapter is as much about curriculum development as it is about blood. The existing reading lesson works. The question is whether a new hands-on model can make the science more visible without becoming activity for activity's sake. |
|---|
In this chapter, you will see...
| FOCUS | WHAT TO EXPECT |
|---|---|
| THE BASELINE LESSON | OpenSciEd devotes three days to microscope use, blood observations, reading, and discussion. My established version is much simpler: a strong text, a reading strategy, and direct sense-making. |
| RECIPROCAL TEACHING | The Predict–Question–Clarify–Summarize four-square gives students a repeatable way to read technical text rather than merely answer comprehension questions. |
| MICROSCOPES, REPOSITIONED | I still use the blood smear and scientific sketching, but I moved that work into a separate microscope lesson so microscope skills do not consume the blood-content lesson. |
| THE HANDS-ON SEARCH | Bag of Blood, component stations, circulation-role stations, the Carolina kit, and a whole-class circulation model are candidates—not finished recommendations. |
| PILOT BEFORE PURCHASE | A small resource class can become a low-risk test bed for one Carolina kit before I spend money scaling an activity that may not survive first contact with students. |
| THINK TWO YEARS OUT | This chapter documents a development cycle: establish the learning target, protect a dependable fallback, pilot cheaply, observe what students actually learn, revise, and scale only after the activity earns its place. |
What stays protected
Blood is a mixture • RBCs / WBCs / platelets / plasma • structure → function • blood vessels as pathways • transport throughout the body • connection to injury and healing
What is still being tested
Which hands-on model is worth the time; whether Bag of Blood becomes the default; whether stations model composition or circulation better; how the Carolina kit fits; whether a whole-class skeleton model is worth building; what should happen this year versus next year.
|
THE CHAPTER TAKEAWAY A lesson does not need to be broken before it can be rebuilt. Sometimes the professional work is deciding whether a dependable lesson is good enough—or whether a new model can make the thinking more visible. |
|---|
Lesson 4: Blood — The Lesson I Haven't Solved Yet
Why a perfectly serviceable blood-reading lesson became a case study in choosing, piloting, rejecting, and refining better activities over more than one school year.
I do not have a dramatic before-and-after story for Lesson 4.
Most years, I teach the blood content through a reading. It works. Students learn that blood is a mixture, that it contains red blood cells, white blood cells, platelets, and plasma, and that those components have different jobs. We connect structure to function. We move on.
The problem is not that the lesson fails.
The problem is that blood is too important to the rest of the unit for me to stop asking whether I can make the learning more concrete.
Not every lesson needs a finished replacement. Sometimes the professional work is deciding what is worth trying next.
The baseline is stronger than it looks
OpenSciEd's full Lesson 4 is ambitious. It spans three days: one largely devoted to microscope orientation and scale, one to microscopic observations of human and mammal blood, and one to reading and discussion about blood components and their functions. The lesson is designed so students first notice that blood is a mixture, then see microscopic structures, and finally use text to name those components and connect structure to function.
The intellectual sequence is legitimate. But I no longer need the blood lesson to carry the full burden of teaching microscope use. I have separated that work into a dedicated microscope lesson, where students can learn the tool, sketch what they see, and work with a blood smear without asking the blood-content lesson to do two jobs at once.
|
THE NON-NEGOTIABLE OUTCOME Students should leave knowing that blood is a flowy mixture made of red blood cells, white blood cells, platelets, and plasma; that those components have different functions; that their structures support those functions; and that blood vessels provide a pathway that lets blood move materials throughout the body. |
|---|
What OpenSciEd is trying to build
The official lesson moves deliberately across scales. Students begin with the whole-body distribution of blood vessels and the visible separation of a blood sample into layers. They then use microscopes to reveal components that cannot be seen with the unaided eye. Finally, they read to identify the components and connect their structures with their functions.
That progression matters. The reading is not supposed to be an isolated information dump; it is meant to explain patterns students have already observed.
When I strip the lesson down to its intellectual architecture, I see a sequence worth protecting:
Blood is everywhere → blood is a mixture → the mixture has components → each component has a job → structure helps it do that job.
|
PROTECTED ARTIFACTS 1) Evidence that blood is found throughout the body. 2) A clear representation of the four major blood components. 3) Structure/function thinking for those components. 4) A connection back to the injured foot: why would damaged tissue need access to blood? |
|---|
What I have done: mostly make the reading work better
I have not historically rebuilt this lesson around a big lab. Most of the time I focus on the blood reading and use the lesson as an opportunity to teach students how to read difficult informational text.
That is less glamorous than a circulating-fluid model or a room-sized simulation, but it is dependable. The blood content is compact enough that a good reading strategy can get students where they need to go without pretending that every important idea has to become a laboratory.
Modification #1: Use Reciprocal Teaching instead of a worksheet
My preferred reading routine is Reciprocal Teaching. Students divide a notebook page into four squares: Predict, Question, Clarify, and Summarize.
I read a manageable section aloud first. Students then reread it themselves, annotate the text, and add ideas to the four-square. We repeat that cycle with the next section. The goal is not to fill four boxes for the sake of filling boxes. The goal is to make the invisible work of comprehension visible.
The four-square is the record. Reciprocal Teaching is the thinking routine.
What Reciprocal Teaching is actually doing
The original Reciprocal Teaching model uses four comprehension moves—predicting, questioning, clarifying, and summarizing—inside teacher-student dialogue. The teacher initially models the moves and then gradually shifts more of the responsibility to students.
That matters because the routine is not simply a four-box graphic organizer. The power is in repeatedly asking students to anticipate meaning, notice confusion, repair that confusion, and compress what they learned into a useful summary.
| MOVE | WHAT STUDENTS DO | WHY IT MATTERS |
|---|---|---|
| PREDICT | Use headings, images, prior knowledge, and the previous section to anticipate what comes next. | Activates background knowledge and gives students a purpose for reading. |
| QUESTION | Generate a question the section answers—or a question the section creates. | Makes students monitor meaning instead of simply moving their eyes across the page. |
| CLARIFY | Identify a confusing word, sentence, diagram, or idea and work out what it means. | Normalizes confusion as part of reading and teaches students to repair comprehension. |
| SUMMARIZE | State the most important idea in their own words. | Forces students to decide what matters and creates a study-ready record. |
How I use the four-square with the blood reading
I do not hand students the whole article and say, 'Fill this out.' I chunk the text. I model one section. We annotate together. Then students reread and add to the four-square. As the lesson continues, I do less of the thinking aloud and students do more.
|
A PRACTICAL ENDPOINT A successful product is a well-annotated blood text plus a four-square containing useful predictions, real questions, clarified vocabulary/ideas, and concise summaries—not four boxes packed with filler. |
|---|
The reading does not have to be the lesson forever
Even if I eventually replace the reading as the central class activity, I would still give students the text.
It can become an at-home reference for the unit study guide, a makeup resource, a study-hall task, a filler activity when students finish early, or simply a second explanation for a student who needs one more pass at the content.
That changes the question from 'Do I keep the reading or replace it?' to something more useful:
Which job should the reading do?
A resource does not have to be the central learning experience in order to remain valuable.
Modification #2: Move the microscope work to a microscope lesson
I do still use blood under the microscope. Students observe the smear and make scientific sketches. I just no longer need that work to live inside Lesson 4.
Putting microscope orientation, focusing, magnification, field of view, and scientific sketching into a separate microscope lesson lets the blood lesson focus on blood. Then the microscopic image becomes evidence students already know how to collect rather than the excuse for an entire tool-training day.
|
THE SHIFT Old structure: learn the microscope → practice → observe blood → read about blood. My current structure: learn microscopes in a dedicated lesson; let Lesson 4 focus on what blood is, what its components do, and why injured tissue needs it. |
|---|
The activity I am still trying to find
This is where Lesson 4 becomes a design chapter rather than a finished lesson.
The reading works. That means a replacement has to earn its place. 'Hands-on' is not enough. A new activity has to make the structure of blood, the functions of its components, or the importance of circulation easier to understand than the dependable reading does.
I am especially interested in activities that let students manipulate a model, make a prediction, change a condition, and then explain what happened.
|
MY TEST FOR A NEW ACTIVITY Can students use the model to explain something they could not explain as clearly before? If not, the activity may be engaging, but it has not yet earned instructional time. |
|---|
Candidate #1: Make a Bag of Blood
This may be the cleanest direct replacement for the reading-centered blood-composition lesson. Each group builds a physical model of blood: a liquid portion representing plasma, many red pieces for red blood cells, a smaller number of larger white pieces for white blood cells, and tiny pieces representing platelets.
| BLOOD COMPONENT | POSSIBLE MODEL | QUESTION THE MODEL MUST ANSWER |
|---|---|---|
| Plasma | Yellow-tinted water | Why does blood need a liquid portion? |
| Red blood cells | Red beads / pom-poms | Why are there so many, and what are they transporting? |
| White blood cells | Larger white beads | Why are there fewer, and when do they matter? |
| Platelets | Tiny beads / confetti / sticky pieces | Why would tiny sticky pieces help when a vessel is damaged? |
The important move comes after building it. Students apply the model to scenarios: a cut, a fracture, an infection, exercise, dehydration, or a blockage. Now the bag is not a craft. It is something students have to use to explain a changing biological situation.
Candidate #2: Turn the bloodstream into stations
A second possibility is to make the classroom itself a circulation model. Stations represent locations where materials are exchanged or problems arise.
At the lungs, red blood cells trade carbon dioxide for oxygen. At body tissues, they deliver oxygen and pick up carbon dioxide. Plasma can carry nutrients from an intestine station and wastes away from tissues. Platelets can respond to a cut or laceration station. White blood cells can respond to an infection station.
I could also give students roles and have them physically circulate around the room. That would shift the content from 'what are the parts of blood?' toward a more dynamic question: 'What does blood accomplish by moving everywhere?'
The question is not whether students are moving. The question is whether the model makes the movement of matter easier to understand.
Download the complete 22-page Bloodstream Role-Play with role cards, six station signs, printable tokens, student capture sheets, and debrief guidance.
Download the Role-Play PDF →Candidate #3: 'Who saved the broken foot?'
Another version would keep the unit phenomenon even tighter. Four short stations could each represent one blood component. Every task would end with the same question: How could this component matter near the broken metatarsals?
-
RBC station: move oxygen tokens through a constrained pathway to
injured tissue.
Plasma station: model a fluid medium carrying dissolved materials.
Platelet station: patch or plug a simulated vessel leak.
WBC station: respond to a simulated infection or foreign material.
That keeps the blood lesson from becoming a generic human-body detour. The injured foot remains the reason to care.
Candidate #4: Use the Carolina kit—but do not force it into the wrong job
The Carolina circulatory-system kit is appealing because it gives students real tubing, pumps, and one-way valves. That makes it promising for modeling flow, closed loops, direction, blockage, and the relationship among vessels and a pump.
But that is a different instructional problem from teaching the composition of blood. The kit is better suited to the question 'How does blood get everywhere?' than 'What is blood made of?'
That distinction matters. A good piece of equipment can still be the wrong tool for the learning target.
|
POSSIBLE PILOT Use one Carolina kit with the resource class, where there is time to slow down, test the directions, see what misconceptions appear, and discover whether the model is worth scaling. If the activity earns its place, order more later. |
|---|
Candidate #5: Build the circulation model into the classroom skeleton
I am also intrigued by a whole-class model rather than a full set of kits. The classroom skeleton could become the frame for tubing or visible pathways that represent vessels. A pump and one-way valves could make flow visible without requiring a major purchase.
That kind of model would not replace individual student reasoning, but it could become a durable reference for later discussions about injury, circulation, nerves, cells, and transport.
The question is whether I can build something simple enough to use repeatedly instead of a clever demonstration that takes hours to construct and five minutes to understand.
OpenSciEd vs. my rebuilt Lesson 4
| ELEMENT | OPENSCIED ROUTE | MY CURRENT / EMERGING ROUTE |
|---|---|---|
| Time | Three days | One focused blood-content lesson, with microscope work moved elsewhere; future hands-on extension still being tested. |
| Microscope training | Large portion of Day 1 is devoted to discovering microscope use and scale. | Teach microscope skills in a separate microscope lesson. |
| Blood observation | Human slide + animal images at several magnifications. | Keep the blood smear/sketching in the microscope lesson; reuse images as evidence if helpful. |
| Reading | Core Day 3 sense-making activity. | Still valuable; use Reciprocal Teaching or keep as reference / study-hall / makeup resource. |
| Blood components | Names and functions emerge after microscope observations and reading. | Teach the four components efficiently, then spend reclaimed time applying the ideas. |
| Structure/function | Reading + discussion | Protect strongly; whichever activity replaces the reading must make this relationship visible. |
| Hands-on component model | Not central to published lesson. | Bag of Blood or four-component stations are leading candidates. |
| Circulation model | Whole-body vessel image and discussion. | Possible role-play stations, Carolina kit pilot, or whole-class skeleton/tubing model. |
| Healing connection | Students begin connecting blood back to injury. | Make the broken foot a repeated application question rather than a brief end-of-lesson connection. |
| Development status | Published sequence is complete. | Established reading routine + separate microscope lesson; hands-on replacement is intentionally still in R&D. |
What I am protecting, compressing, and still questioning
| PROTECT | COMPRESS | STILL TESTING |
|---|---|---|
| Blood as a mixture; RBC/WBC/platelet/plasma functions; structure → function; vessels as pathways; transport; connection to the injured foot. | Open-ended microscope discovery; repeated observation tables; multiple animal comparisons; extended share-outs; full Scientists Circle; Progress Tracker/DQB time if another artifact captures the thinking. | Bag of Blood as default; four-component stations; circulation stations/role-play; Carolina kit; skeleton model; how much preliminary healing connection belongs here. |
The version I want to try this year
I do not need the final two-year version this September. I need a useful pilot.
|
OPTION A - THE DEPENDABLE VERSION Use the blood-vessel / separated-blood hook, teach with the Reciprocal Teaching text, complete a concise structure-function organizer, and connect each component back to the injured foot. Keep the text as the default when time, materials, or a pilot activity does not cooperate. |
|---|
|
OPTION B - THE PILOT Use the same content target, but replace part of the reading time with one hands-on model—most likely Bag of Blood or a tightly structured component-stations lesson. Give students the text anyway as a reference rather than making the new activity carry every detail. |
A two-year development cycle
| WHEN | WHAT I DO | WHAT I AM TRYING TO LEARN |
|---|---|---|
| This year - small pilot | Try one new activity with one or two classes; use the resource class for the Carolina kit if appropriate. | Do students actually reason with the model? Where does it confuse them? What materials fail? How long does it really take? |
| This year - revise | Keep notes, photos of setup, student products, and a short post-lesson reflection. | What should be cut, directly taught, reordered, or added before scaling? |
| Next summer | Choose the strongest model and build clean directions/materials. | Can another teacher understand and run the activity without needing the version that exists only in my head? |
| Next year | Scale the activity across classes if it has earned the investment. | Does the rebuilt version outperform the dependable reading strongly enough to become the new default? |
A pilot is allowed to be unfinished. Its job is to teach the teacher something.
The bigger point
Lesson 4 may end up being one of the most useful chapters in this project precisely because I have not solved it.
Curriculum revision is often written backward. We show the polished lesson after the failed versions have disappeared. That can make improvement look like inspiration: teacher sees problem, teacher invents brilliant replacement, students love it, end of story.
That is not how this one looks.
I have a dependable reading lesson. I have a reading routine I trust. I have moved microscope work somewhere it makes more curricular sense. Now I have several possible hands-on replacements, none of which I am ready to call the answer.
So the professional work is selection: What is the actual learning target? What does the current lesson already do well? Which weakness am I trying to solve? What is the cheapest version of a new idea that I can test? What evidence will tell me whether it worked? What can wait until next year?
The goal is not novelty. The goal is a better explanation of blood and a stronger connection to the healing phenomenon.
Sources & design notes
Primary curriculum source
OpenSciEd. Unit 6.6, Lesson 4 Teacher Edition, “Why is there blood in all of these places in the body?” Version dated 2/9/22. Curriculum screenshots in this chapter are excerpted from the user-provided Teacher Edition for commentary, comparison, and instructional analysis.
The published lesson is a three-day investigation involving microscope orientation, microscopic blood observations, reading, structure/function sense-making, systems thinking, and a transition to nerves.
Reciprocal Teaching
Palincsar, A. S., & Brown, A. L. (1984). Reciprocal Teaching of Comprehension-Fostering and Comprehension-Monitoring Activities. Cognition and Instruction, 1(2), 117–175. The framework emphasizes predicting, questioning, clarifying, and summarizing in dialogue with gradual transfer of responsibility.
Author's note
Established practice: reciprocal-teaching reading routine, distributing the blood text as a student resource, and moving microscope skills and blood sketching into a separate microscope lesson. Active experiments: Bag of Blood, simplified component stations, body-location circulation stations, using one Carolina kit with a small class, and a possible whole-class circulation model built around the classroom skeleton.
Return to top ↑LESSON 4 | CONDENSED MODIFICATION GUIDE
Unit 6.6 • Injuries & Healing
| THE GOAL Figure out what blood is made of, what each component does, and why a flowy mixture moving through vessels is useful throughout the body. |
|---|
PROTECT: blood as mixture • RBCs / WBCs / platelets / plasma • structure → function • vessels as pathways • transport • healing connection
| 1 HOOK WITH BLOOD | Use the whole-body vessel image and/or separated blood tube to establish: blood is everywhere and blood is a mixture. |
| 2 TEACH THE COMPONENTS | Students need red blood cells, white blood cells, platelets, and plasma—plus one useful function for each. |
| 3 USE RECIPROCAL TEACHING | For the text: Predict → Question → Clarify → Summarize. Chunk the reading; annotate; gradually release responsibility. |
| 4 KEEP STRUCTURE/FUNCTION | Ask how liquid plasma, flexible rounded cells, and sticky/branching platelets support their jobs. |
| 5 APPLY TO THE FOOT | For every component ask: Why could this matter near damaged tissue or a broken metatarsal? |
| 6 KEEP MICROSCOPES SEPARATE | Use the blood smear and sketching in the dedicated microscope lesson rather than spending this lesson on tool training. |
| 7 PILOT ONE HANDS-ON MODEL | Best first candidates: Bag of Blood or simplified component stations. Do not try every idea at once. |
| 8 KEEP THE TEXT ANYWAY | Even if the hands-on model wins, the reading can remain a study-guide reference, makeup task, study-hall task, or fallback. |
RECOMMENDED TIMING
|
DEFAULT • ONE 66-MIN PERIOD Blood hook → Reciprocal Teaching / concise notes → structure-function → broken-foot application. |
PILOT • ONE 66-MIN PERIOD Blood hook → short direct setup → Bag of Blood or stations → application scenarios → text kept as reference. |
|---|
CUT FIRST: open-ended microscope discovery • multiple animal tables • extended scale/magnification work • repeated share-outs • full Scientists Circle • lengthy tracker/DQB updates.
|
ONE RULE FOR A NEW TEACHER Do not replace a dependable reading with a hands-on activity just because it is hands-on. Pilot the activity until it explains the science better than the thing it is replacing. |
|---|
Adapted from OpenSciEd Unit 6.6, Lesson 4 • Teacher-use summary
Return to top ↑Lesson 4: Practical Modification Guide
Blood Components, Reading, and Choosing the Next Activity
What this lesson really needs to accomplish
Do not let microscope procedures or a new activity become the lesson. Students need a clear, durable model of what blood is and what its major components do.
|
TARGET Blood is a flowy mixture made of plasma, red blood cells, white blood cells, and platelets. Blood vessels provide pathways that let the mixture move throughout the body. The structures of the components help them perform their functions. |
|---|
Blood vessels are found throughout the body.
Blood is a mixture, not one uniform substance.
Red blood cells carry oxygen.
White blood cells help respond to disease/infection.
Platelets help plug damaged vessels and reduce leaking.
-
Plasma is the liquid medium that carries cells and dissolved
materials.
Structure supports function.
-
These ideas should connect back to why injured tissue needs access to
blood.
What I have done in the past
1. Use the reading as the reliable baseline
The reading lesson works. I would rather acknowledge that than invent a problem. It is a dependable way to teach the content when time or materials make experimentation impractical.
2. Use Reciprocal Teaching
Students create a Predict / Question / Clarify / Summarize four-square. I chunk the reading, model the routine, have students reread and annotate, and gradually shift more of the work to them.
3. Move the microscope investigation elsewhere
Blood-smear observation and scientific sketching still happen, but in a separate microscope lesson where the instructional target is using the tool and recording microscopic evidence.
If you just want to do the reading
| SQUARE | STUDENT THINKING | TEACHER MOVE |
|---|---|---|
| Predict | What do I think this section will explain? What clues am I using? | Model a plausible prediction from the heading/image, then move quickly to student-generated predictions. |
| Question | What question does this section answer? What new question do I have? | Push beyond factual recall: 'What are you still trying to understand?' |
| Clarify | What word, sentence, diagram, or idea is confusing? What helps me resolve it? | Model rereading, using context/images, breaking words apart, or asking a partner. |
| Summarize | What is the most important idea in my own words? | Require compression rather than copying; one or two useful sentences are enough. |
|
SUCCESS LOOKS LIKE A well-annotated text plus a four-square students can actually study from. The organizer should make comprehension visible—not become another packet. |
|---|
What I am considering now
1. Bag of Blood
Best candidate for composition. Students physically build a model of the four major blood components and then use it to explain injury, infection, exercise, dehydration, or blockage scenarios.
2. Component stations
Four short tasks—RBC, plasma, platelets, WBC—can keep the focus on what each component contributes and why it could matter near the injured foot.
3. Circulation / body-location stations
Students circulate through lungs, intestines/body tissues, infection, and injury stations exchanging tokens. Best for transport and circulation rather than blood composition.
4. Carolina circulatory-system kit
Use primarily to model pumps, tubing, one-way flow, closed loops, blockage, and vessel networks. Pilot with a small class before buying enough to scale.
5. Whole-class skeleton model
Potential low-cost visual model for tubing and circulation pathways. Worth pursuing only if it becomes a reusable thinking tool rather than a one-time prop.
My current recommendation
For this year, keep the Reciprocal Teaching reading as the safety net and pilot one hands-on model. Give students the text regardless. If the pilot works, revise it. If it does not, the unit still has a dependable lesson.
|
DEVELOPMENT RULE Change one major variable at a time. If I try Bag of Blood, circulation stations, a Carolina build, and a new reading routine simultaneously, I will have no idea which part improved—or damaged—the lesson. |
|---|
What to cut first
The full day of open-ended microscope orientation.
Millimeter graph-paper measurement at every objective.
Extended refraction/lens discussion.
Multiple human/animal observation tables.
Repeated partner and Scientists Circle share-outs.
Detailed stain-color discussion.
Long Progress Tracker and DQB updates.
Optional ratios/percentages extension.
What not to cut
Blood is found throughout the body.
Blood is a mixture.
RBCs, WBCs, platelets, and plasma.
A useful function for each component.
Structure-function relationships.
Blood vessels as transport pathways.
Connection to the injured foot and healing.
One rule for a teacher new to the curriculum
Return to top ↑A dependable reading is not a failure. Keep it until the replacement earns the right to become the lesson.