How could we see this?

Is an atomic structure a photograph?

Trace diffraction measurements through model fitting and validation, distinguishing spatial resolution from display magnification.

Select the sample, diffraction, coordinate-model and rendering stages to inspect how experimental evidence supports a molecular view. The chain uses identified hemoglobin metadata and explains what each stage contributes. Its diffraction explanation is not a displayed experimental diffraction image; the separate Bragg activity illustrates a simpler model.

Explore the model (optional)

EXPLORE THE MODEL

From specimen to structural interpretation

Focus: Specimen
Context: Protein crystal
Relationship: Physical sample

An evidence chain based on the 1A3N record. Raw diffraction images are not bundled; selected deposited coordinates are rendered separately.

Evidence stage

FocusSpecimen

ContextProtein crystal

RelationshipPhysical sample

X-ray diffraction experiments use a prepared protein crystal. The preparation matters; it is not an unmodified blood cell.

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A SEPARATE INTRODUCTORY MODEL

EXPLORE THE MODEL

Read a diffraction angle

FOLLOW THE SIGNALConceptual instrument diagram

Plane spacing: 0.20 nm

The arrangement explains the signal path. The investigation below supplies the teaching output; this schematic is not a ray trace, micrograph, or instrument calibration.

View sampled plot values

Current values

Scattering angle 2θ (degrees)	Illustrative diffraction signal
0.000	0.00000
6.000	0.00000
12.000	0.00000
18.000	0.00000
24.000	0.00000
30.000	0.22035
36.000	0.00000
42.000	0.00000
48.000	0.00000
54.000	0.00000
60.000	0.00000
66.000	0.00000
72.000	0.00000
78.000	0.00000
84.000	0.00000
90.000	0.00000
96.000	0.00000
102.000	0.00000
108.000	0.00000
114.000	0.00000
120.000	0.00000
126.000	0.00000
132.000	0.00000
138.000	0.00000
144.000	0.00000
150.000	0.00000
156.000	0.00000
162.000	0.00000
168.000	0.00000
174.000	0.00000
180.000	0.00000

Calculated first-order diffraction from one family of ideal planes. The illustration is not a protein diffraction dataset.

Plane spacing0.2 nm

X-ray wavelength0.1 nm

TEACHING RELATIONSHIPλ = 2d sin θ

Plane spacing0.20 nm

Scattering angle 2θ28.96°

Path difference0.10 nm

Constructive interference occurs at this angle for the selected ideal plane spacing. One peak is not a full structure solution.

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HOW DO WE KNOW?

Evidence & limits

Reference science + bounded teaching model

What this interaction establishes

Trace diffraction measurements through model fitting and validation, distinguishing spatial resolution from display magnification.

An evidence chain based on the 1A3N record. Raw diffraction images are not bundled; selected deposited coordinates are rendered separately.

Source bindings for this explanation

Start here

Sources: S08, S20, S12, S09.

Explore the science

The sample stage describes the specimen behind an identified experiment. The diffraction stage explains measured scattered intensities, while a coordinate model is an interpretation constrained by those measurements and additional analysis. Rendering turns selected coordinates into an inspectable graphic. Reference entry 1A3N reports deoxygenated human hemoglobin determined by X-ray diffraction at 1.80 Å resolution. Its metadata belongs to that record, not to the synthetic single-plane peak in the accompanying Bragg activity.

Sources: S08, S20, S12, S09.

Go deeper

A real crystallographic analysis combines reflections, phasing, model building and validation; the explanatory chain compresses those operations. No experimental diffraction image or electron-density map is being reconstructed by its stage selector. The separate Bragg model shows how one ideal plane spacing relates to a diffraction angle, not how to solve hemoglobin. Coordinate rendering adds no experimental detail: enlarged atoms remain a visualization of the selected record, whose missing information and revision must stay visible.

Sources: S08, S20, S12, S09.

Limitations

The evidence chain explains stages and reference metadata; it does not display or reconstruct a measured hemoglobin diffraction image or electron-density map. The accompanying Bragg peak is synthetic and describes one ideal plane family, not the hemoglobin dataset. A coordinate rendering is an interpreted view; display enlargement does not improve experimental resolution or validate every functional claim.

Sources: S08, S20, S12, S09.

Keep these boundaries in mind

The evidence chain explains stages and reference metadata; it does not display or reconstruct a measured hemoglobin diffraction image or electron-density map.
The accompanying Bragg peak is synthetic and describes one ideal plane family, not the hemoglobin dataset.
A coordinate rendering is an interpreted view; display enlargement does not improve experimental resolution or validate every functional claim.

Inspect the references

Supplemental primary reference ↗Supplemental primary reference ↗

Scientific explanations with linked references. Model calculations retain their stated assumptions and limits.

Optional: check your understanding

MAKE THE CONNECTION YOUR OWN

Test your reasoning

Try freely. Saving progress is optional.

recognition

Which item is the coordinate model?

The fitted set of atomic positions used to render the moleculeOnly the raw detector intensitiesThe microscope’s physical lens

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mechanism

What changes when you enlarge a rendered molecule by ten times?

The dataset’s resolution improves tenfoldThe display size changes while experimental information stays the sameTen times as many reflections are collected

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evidence

Suppose a deposited model includes a region with weak experimental support. What should accompany a detailed rendering of that region?

A claim of complete certaintyRemoval of all experimental metadataA visible statement of uncertainty or missing information

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transfer

A reconstruction algorithm fills a blurred gap in an image. What should a scientific explanation distinguish?

Observed data from inferred or generated detailOnly the most attractive color schemeThe computer model from the evidence by deleting the evidence

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