CIRCUITS AND PATHWAYS END-OF-UNIT ASSESSMENT
MYSTERY BOXES SCORING INSTRUCTIONS
The purpose of the Circuits and Pathways end-of-unit assessment is to determine if students can use their knowledge of
circuits to solve problems. Specifically, students are asked to identify the circuit components hidden inside each of the
six mystery boxes.
The assessment is scored on the basis of student responses for each of the six lettered mystery boxes. Students’
responses are scored on the basis of: (a) answer, correct identification of the components of each box, and (b) evidence,
the quality and completeness of the tests and observations used to determine the contents of each box.
Scoring Rationale:
A unique combination of tests and observations provide the evidence needed to correctly identify the contents of each
box.
Testing a box with just a bulb indicates whether or not there is a battery inside. The brightness of the bulb indicates
what else is in the circuit. In most cases, this is not a unique identification and a second test is necessary:
Test
Bulb
Bulb
Bulb
Bulb
Bulb
Observation
off
on
regular/normal
bright
dim
Indicates the box contains
no battery
a battery
1 battery
batteries
battery & bulb
Comments
eliminates A & D
considered vague; eliminates B, C, E
not an option; eliminates B, C, E
identifies Box D
identifies Box A
Although testing with just a battery or a wire is not preferred since ‘success’ indicates a short circuit, both tests can
yield useful results. The battery-only test requires an additional test to actually identify the contents:
Test
Battery
Wire
Observation
hot
hot
Indicates the box contains
wire or batteries
just batteries
Comments
eliminates A, C & E
identifies Box D
If there is no battery in the box, the student must add one to the exterior circuit in order to light the bulb. The brightness
of the bulb can be used to identify the contents of the box in some cases (D & E). In other cases a second test (or a
different test) is required to distinguish between the remaining possibilities:
Test
Battery & bulb
Battery & bulb
Battery & bulb
Battery & bulb
Battery & bulb
Observation
regular/normal
on
off
dim
very bright
Indicates the box contains
1:1 ratio batteries & bulbs
complete circuit
nothing or battery
bulb
batteries
Comments
eliminates C & E
considered vague; eliminates C
eliminates B & D
identifies Box E (1 battery/2 bulbs)
identifies Box D (3 batteries/1 bulb)
There are other tests or combinations of tests that students can perform that will yield the correct answer (see score form
for some examples). Since the Ss cannot see the orientation of the battery inside the box, it is possible for them to put
the external battery in the opposite direction which could make it appear that there was no battery inside (relevant to
Box A and Box D) thus two tests must be performed to determine why the bulb is off when testing with bulb & battery.
Steps in Scoring
Look at the simple circuit drawn by the student on page 1. If the drawing is reasonably clear and correct (wires touching
4 distinct contact points on bulb/holder and battery/holder; reasonable rendition of bulb), score the simple circuit as “1;
if the simple circuit is missing or incorrect (wires not clearly touching contact points, bulbs rendered in such a way that
their CCPs are unclear…), score the simple circuit as “0”. Fill in the student description of brightness (note “beams” if
student drawing has light beams but no written description is given). It is also useful to see how the student draws
batteries, bulbs, etc. If the student labels this circuit as “bright” rather than “normal” (or “regular”) it is OK to substitute
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‘bright’ for normal on pages 3 through 8 but student must indicate that Box D is brighter than a simple (1 battery 1
bulb) circuit (i.e., must say ‘very bright’ or make appropriate comparison to their simple circuit). Student’s label of
brightness of the simple circuit should not hurt them in the assessment.
FOR EACH LETTERED BOX, record the answer and quality of evidence scores on the score form.

STUDENT ANSWER

Write down the letter corresponding to the student’s response:
A – Battery & Bulb
B – Wire (OR Wires)
C – Nothing
D – Two Batteries (OR Batteries w/o #)
E - Bulb (OR Bulbs)
X – Blank (no answer)
Y – Battery
Z – Any other answer (not one of the options)

QUALITY OF EVIDENCE
Using drawings and explanations as evidence, score the tests the student carried out and the observations they
made. Evidence is scored whether or not the student correctly identified the contents of the box.

In the “Evidence score for Correct Answer” column, use the evidence descriptions in same row as the correct
answer

In the “Evidence Score for STUDENT Answer” column, use the evidence descriptions in the row
corresponding to the box containing the student’s answer (e.g., if the student answers “bulb” for box A, use the
Quality of Evidence descriptions for Box E (bulb) for this column)

Tests should be accompanied by an observation. This observation could either be in the written explanation
(e.g., “the bulb was dim”), or in the picture (e.g., “shine” marks around the bulb as evidence that the bulb lit).
Evidence should be judged holistically. Drawing(s) and written explanation together should yield a complete
response (e.g., student doesn’t have to draw both tests if their written explanation makes it clear that they did
appropriate tests and comparisons).
Vague responses which do not distinguish the comparative brightness of the bulb (such as “light on” or “lit”
instead of “dim” or “bright” in the evidence boxes) should receive a Vague Evidence score (1).
Quality of evidence is judged as follows:



Complete Evidence:
Student has included all of the necessary tests and corresponding observations to
correctly and uniquely identify the contents of a box.
Complete evidence receives a score of 3 in evidence score box.
Incomplete Evidence:
Student has included some, but not all of the evidence necessary to correctly
identify the contents of the box. The student may have: (a) reported one but not
both tests, or (b) performed an insufficient test (e.g., testing Box E with just a bulb
in circuit). In either case, the observation must be correct.
Test(s), whether or not accompanied by observations, should eliminate one or more
choices but not uniquely identify a box.
Incomplete evidence receives a score of 2 in evidence score box.
Vague Evidence/
Student has provided: (a) test with vague or inaccurate observations (e.g.,
Innaccurate Observation: picture labeled “lit” rather than bright or dim)
Observations that are a ‘half step’ off are considered inaccurate rather than incorrect
(e.g., “regular” instead of “dim” or “bright”; “dim” instead of “off).
Students are not penalized for including superfluous tests that don’t yield additional
information
Vague evidence receives a score of 1 in the evidence score box.
Incorrect Observation/
No Evidence:
Student has provided: (a) test with no observations (e.g., picture only, or “I tried
it”) or (b) incorrect observations
Observations that are more than a “half step” off are considered incorrect (e.g.,
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CIRCUITS AND PATHWAYS END-OF-UNIT ASSESSMENT
“bright” instead of dim or “on” instead of off)
Incorrect observations receive a score of 0 in the evidence score box.
Evidence scoring for Student Answer “Y” (singlebattery):
Test….……..Observation
Quality of Evidence
Incomplete Evidence (2)
Vague Evidence/
Inaccurate Observation (1)
Test………...Observation Test……...Observation
Incorrect Observation/
No Evidence (0)
Test……...Observation
Bulb..………..….…Regular
Battery & Bulb………...Off
Bulb……….……..…..Off
OR
OR
Bulb...…...….…...Dim/Bright
OR
Bulb.....…………..……….On
Battery &
Bulb……………...….Bright
Wire………………...….Hot
OR
Battery &
Bulb…..…….……....Dim
Complete Evidence (3)
OR
Battery &
Bulb….…....….....On/Regular
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