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Quizzes > Science

Blood Spatter Test: Practice Forensic Pattern Analysis

Quick, free blood spatter quiz. Instant results to check your understanding.

Editorial: Review CompletedCreated By: Can DangUpdated Aug 23, 2025
Difficulty: Moderate
2-5mins
Learning OutcomesCheat Sheet
Paper art style red blood spatter shapes on sky blue background with bold quiz title text

This blood spatter test helps you practice reading drops, spines, and angles so you can interpret impact patterns with confidence. Use it to spot study gaps before a lab, class, or exam and get instant results. To round out your skills, review motion and force in our basic physics quiz, build core knowledge with biology multiple choice questions, and refresh lab terms with a phlebotomy practice test.

Which pattern best indicates blood expelled under pressure from a breached artery?
Fine mist distributed uniformly across walls
Large circular pools with smooth edges
Random small round droplets with no directionality
Linear, wave-like arcs with periodic surges consistent with pulse - arterial spurt due to pressure and pulsation
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A bloodstain is 6 mm long and 3 mm wide. The angle of impact is approximately arcsin(width/length).
True
False
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On a rough surface like unfinished wood, what feature commonly forms around the main droplet due to disruption of its edges?
Skeletonized rim
Void pattern
Serum halo
Satellite stains - small secondary drops from edge breakup on impact
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The spine of a bloodstain refers to which part of a drop?
The thinnest part within a clot
The central darkest region of a passive drop
Narrow elongations radiating outward from the main stain toward the direction of travel - spines indicate directionality
Raised ridge along the perimeter of a dried pool
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Expirated blood often contains which distinguishing feature?
Airway-origin bubble rings or mucous strands - indicates blood expelled from mouth or nose
Uniform circular drops only
Sharp-edged linear voids
Dilute serum rings from drying
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Which presumptive test turns pink in the presence of blood due to peroxidase-like activity?
Phenolphthalein (Kastle-Meyer) - turns pink when reduced indicator is oxidized
Takayama crystallization test
Leucomalachite green gives blue glow
Luminol chemiluminescence
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A void pattern suggests an object blocked blood deposition, leaving a clean area outlining the object's shape.
False
True
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Which best distinguishes a wipe from a swipe?
Both terms are interchangeable
Wipe is transfer from a wet source; swipe disturbs dried blood
Swipe always follows gravity; wipe does not
Wipe is from a moving clean object through wet blood; swipe is from a moving bloodied object onto a clean surface - key difference is which is moving and where blood starts
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Back spatter in firearm events most commonly travels toward the shooter from the entrance wound.
False
True
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Which feature helps determine the direction of travel of an elongated droplet?
Tail points toward the origin
Edges are symmetric so direction is indeterminable
Tail points in the direction of travel - the narrow end indicates motion
The darkest region points to origin
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Which observation supports expirated blood rather than impact spatter?
Uniform droplet size 3 to 4 mm
Deflection by wind only
Presence of gunpowder stippling
Bubble voids that collapse into ring-shaped residues - air from lungs creates bubbles
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Point of origin in 3D is located where the back-projected trajectories intersect above the point of convergence.
False
True
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Which factor most increases satellite formation around impact stains?
High humidity only
Lower viscosity from cooling
Low fall height onto smooth glass
High surface roughness and higher impact energy - promotes edge breakup and satellite droplets
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Luminol reacts with the iron in hemoglobin to produce blue chemiluminescence in the dark, but it can yield false positives with some oxidants.
False
True
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Which statement about drying time of bloodstains is most accurate?
It is influenced by volume, surface, temperature, and airflow - only rough estimates are possible
It is unaffected by temperature and humidity
It provides exact time since deposition
It is faster on porous surfaces only due to absorption
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Which describes skeletonized transfer?
A dry object removes only wet centers, leaving a ring and transferring an outline - indicates partial drying before contact
Fine mist from coughing
A void in spatter behind an object
A complete mirror image of a bloody hand on glass
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Fly artifacts can mimic impact spatter but often show what distinguishing trait?
Presence of mucous strands
Paired stains with curved tails pointing both directions
Random tiny stains with digestive halos or specks and location near light sources - insect activity signs
Consistent elliptical shapes with tails
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Area-of-origin reconstruction assuming straight-line trajectories ignores droplet air drag and can overestimate height for shallow angles.
True - neglecting drag bends true paths downward, so straight back-projection intersects higher than reality
False
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Which environmental factor most risks false positives with luminol at a scene?
Recent painting
High humidity alone
Low ambient light
Household bleach containing oxidizers - catalyzes chemiluminescence
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Gunshot back spatter can be drawn into the muzzle or intermediate spaces, producing so-called blowback.
False
True
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Study Outcomes

  1. Understand blood and blood spatter fundamentals -

    Learn the core principles of blood and blood spatter analysis, including pattern types, terminology, and their forensic relevance.

  2. Identify arterial blood spatter characteristics -

    Recognize the unique features of arterial blood spatter to distinguish high-pressure spurts from other bloodstain patterns.

  3. Analyze 90 degree blood drop -

    Examine the shape and diameter of circular drops to determine perpendicular impacts and reconstruct crime”scene events.

  4. Apply angle of impact calculations -

    Use the angle of impact practice answer key to measure bloodstain trajectories and calculate impact angles accurately.

  5. Interpret spines definitions in forensics -

    Understand how spines form on bloodstains and what their presence reveals about the dynamics of bloodshed.

  6. Evaluate quiz performance for targeted skill improvement -

    Review your results against the practice answer key to identify strengths and focus on areas needing further study.

Cheat Sheet

  1. Angle of Impact Calculation -

    Master the formula θ = arcsin(width/length) to determine the angle of impact for blood drops on flat surfaces. For example, a drop with a width of 2 mm and length of 4 mm yields θ = arcsin(0.5) ≈ 30°, a method endorsed by the International Association for Identification. Mnemonic: "Sine Size over Side" helps recall width ÷ length.

  2. Spines and Satellites Identification -

    Differentiate spines (elongated projections) from satellites (small secondary droplets) to infer force and directionality. Spines definition forensics guides you in mapping impact direction by following the tail of each spine away from the target. Research in Forensic Science International shows high-velocity impacts produce more satellites.

  3. Arterial Blood Spatter Patterns -

    Recognize spurting patterns from arterial injuries, characterized by continuous, wave-like droplets. These patterns correlate to systolic pressure, with an average wave frequency of 60 - 100 pulses per minute, providing clues to timing and victim position. Case studies on arterial blood spatter (Journal of Bloodstain Pattern Analysis) highlight distinct color variation during oxygenation cycles.

  4. 90-Degree Blood Drop Analysis -

    At a perfect 90° angle, blood drops form nearly perfect circles - measure diameter directly for volume estimation. Practice with the angle of impact practice answer key: if diameter is 5 mm, the droplet volume approximates 0.06 mL per established forensic tables. Tip: Use graph paper beneath samples to confirm circularity quickly.

  5. Surface Texture Effects -

    Account for target texture: rough surfaces increase spatter irregularity, producing scalloped edges and more satellites. Smooth, non-porous targets (e.g., glass) yield cleaner ellipses, easing length/width measurements. According to FBI Laboratory guidelines, always document substrate type before analysis to avoid interpretive errors.

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