Four fictional cards support five strict before-and-after relationships. Both A-B-C-D and A-C-B-D fit the evidence; B’s 1912–1914 window overlaps C’s 1913 date, so their exact order remains unresolved.
Use the worked example
Move cards from the starting C-D-A-B order using Up and Down buttons. Choose Unresolved for B/C and Check. The result reports the five supported constraints separately from the uncertainty answer. Reordering after a check clears the old feedback. You can activate a Move button with Enter and keep focus on that card’s same direction button for another move.
Explain the evidence for the answer
Keep the event date and the date of its source in different columns. A later account can describe an earlier event. The Library of Congress's timeline teaching post offers context for finding and analyzing sources; the four cards here are invented classroom examples.
For B, the range is uncertainty about when the event occurred. It is not a claim that renovation lasted continuously for three years. Keep that interpretation beside the card.
For this bounded model, an event is provably earlier when its latest possible year is less than the other's earliest possible year. Overlapping or equal-year bounds cannot establish a strict order from these year fields alone.
There are six unordered pairs among four cards. Five have a supported strict direction among these cards; B/C does not. A is first and D last in any compatible list, while B and C can trade positions.
Do not turn before into caused. These fields establish chronology constraints only, not why the facility closed or what the inspection found. Invented names and dates do not support a historical causal account.
A-B-C-D and A-C-B-D both respect the five known relationships. Neither resolves B/C. They are possible linear arrangements consistent with the supplied constraints, not two equally proven historical timelines.
Require a separate B/C status answer: Unresolved. A learner can put B before C on the page and still correctly state that the actual order is not established. The arrangement is a presentation choice; the status is the evidence claim.
An answer that says B definitely before C is unsupported even if its card row is otherwise compatible. Likewise, choosing C definitely before B supplies certainty not present in the record. The useful explanation points to B's inclusive range and C's 1913 event date.
Use A's opening in 1910 and D's closure in 1918 as the anchors. B's renovation falls somewhere from 1912 through 1914, while C's inspection is dated 1913. The source dates are different: A is described in 1920, B is undated, C in 1913, and D in 1919. Read those fields aloud before moving a card.
Check the arrangement and the B/C answer separately. The fixed card controls keep every ID once in the row; Check counts the five supported before-and-after relationships. A compatible row with B definitely before C still has an unsupported uncertainty answer. Ask the student to explain the overlapping dates in writing.
Copy a prompt for this example
Make one HTML chronology activity using four explicitly fictional event cards. Each card must keep its event evidence separate from its source date: A opens in 1910, described by a source published in 1920; B is a renovation sometime from 1912 through 1914, with an undated source; C is an inspection in 1913, recorded in 1913; D closes in 1918, described by a 1919 source.
Start in shuffled order C, D, A, B. Put Move up and Move down buttons beside each card so its ID and both date fields always travel together. Do not add or remove records.
Check five supported constraints: A before B, C, and D; B before D; C before D. B and C have no established strict order because B's window contains 1913. Offer an explicit B/C Unresolved response and a contrasting B definitely before C response.
Accept A-B-C-D or A-C-B-D as compatible arrangements when Unresolved is selected. Display satisfied constraints out of five separately from the uncertainty answer. A correct-looking row must not turn B/C into a proven order.
Include a written-explanation box for teacher discussion. Moving cards or editing the explanation clears old feedback. Reset restores C-D-A-B and blanks the response and explanation. Make the card text readable, keep event dates prominent, and stack the controls within a narrow screen. Return the complete activity as one HTML file.
Ask students which additional event-date evidence would narrow B/C before adapting the activity to a real archive. The prepared HTML can be previewed in NOS while you compare the cards with your maintained workbook. Keep fictional dates labeled as such and never borrow a publication date to fill a missing event date.