Danger Zone: teacher answer key
Public sample teacher key. Includes model answers; open the student worksheet when assigning the activity.
FACS.2.COM.4
Using the worksheet
- Worksheet opens the questions. New questions follow each trial; misses add a reflection prompt.
- Recorded automatically: each completed graded trial: handling plan, prediction category, actual peak category/count, time out and allowed limit, and game result. Sandbox exploration and replays do not add graded worksheet tries.
- My work offers Copy my work and Turn in a PDF. Nothing is submitted automatically. Review written reasoning separately from game success; blank responses remain visible.
- Worksheet answers and completed tries persist on this browser only. Game progress may reset on reload. Predictions are captured at launch and retained with each completed try. Do not enter identifying details.
- On shared devices, use Clear my work and tap again to confirm. The game's Start over does not clear worksheet answers. If browser storage is blocked, export before leaving.
Numbers like "#4" match the printed worksheet. Questions marked "After a miss" appear in the game only after a missed trial; on paper they are combined into one question near the end.
Level 1: Picnic at 75 F
- One passing schedule: table, table, cooler, cooler (two hours out at 75 F). Keeping food on ice throughout also passes. Verify recorded results; not every passing plan is identical.
- The simulated illness line is 2,500 per gram. It is a teaching threshold, not a universal real-world safety boundary.
#1. Compare your predicted and measured count category. How long was the food out, and what was the time limit? FACS.2.COM.4
Use the actual run. At 75 F the modeled limit is 120 minutes. A passing plan must satisfy the time limit AND avoid the illustrative count threshold.
#2. Why does normal appearance or smell not prove that food has been handled safely? FACS.2.COM.4
The appearance stays the same in this model while counts rise. Use safe time/temperature handling, not appearance, as the decision rule.
After a miss: Choose a missed try. What happened, and which rule would guide your next change? FACS.2.COM.4
Use the recorded settings and result, identify the relevant rule, and propose a specific revision. Do not award credit for only copying a correct input.
Level 2: Heat wave at 95 F
- One passing schedule: table, cooler, cooler, cooler. At air temperatures above 90 F the time limit is 60 minutes. Reusing the two-hour plan fails this limit.
#3. Record the same plan at 75 F and 95 F. What changed in the time limit and outcome? FACS.2.COM.4
A two-hour table plan is at the 75 F limit but exceeds the 95 F one-hour limit. Record actual peak counts separately; the model checks both conditions.
#4. In the heat wave, why is two hours on the table followed by ice not enough to pass? FACS.2.COM.4
The two-hour exposure already exceeds the one-hour limit above 90 F. Cooling later does not undo earlier mishandling or reset the accumulated exposure.
After a miss: Choose a missed try. What happened, and which rule would guide your next change? FACS.2.COM.4
Use the recorded settings and result, identify the relevant rule, and propose a specific revision. Do not award credit for only copying a correct input.
Level 3: Leftover chili
- Passing choices in the current game: shallow containers, fridge delay of 0, 60, or 120 minutes, and reheating to 165 F. Immediate refrigeration is the example shown in the game. Whole-pot choices and delays of 180 or 240 minutes fail. These outcomes were checked against all 30 available chili plans.
- Real guidance: refrigerate perishable food within two hours (one above 90 F), divide large amounts into shallow containers, and reheat leftovers to 165 F throughout. Do not infer that a game count certifies real food as safe.
- The game permanently flags threshold crossing. Some toxins can persist after reheating, but the model's threshold, growth curve, cooling constants, and number of sick people are illustrative. It is not a universal pathogen/toxin model.
#5. Record your container, fridge delay, and reheat temperature. Compare center cooling with the edge. FACS.2.COM.4
The large pot's center cools more slowly than its edge. Shallow containers cool faster. Record the actual plan and outcome, including a failed plan.
#6. Why can reheating fail to rescue a plan that was mishandled earlier? Separate the game rule from real food-safety guidance. FACS.2.COM.4
In this game, crossing the illustrative illness line remains a failure even if the final count falls. Some real bacteria can produce heat-stable toxins; reheating is not a way to make mishandled food reliably safe. The exact simulated threshold is not a real safety test.
After a miss: Choose a missed try. What happened, and which rule would guide your next change? FACS.2.COM.4
Use the recorded settings and result, identify the relevant rule, and propose a specific revision. Do not award credit for only copying a correct input.
When a trial missed (#7)
Any of the After a miss answers above. Look for the rule named correctly and the specific thing that went wrong.
Wrap-up
#8. Use a claim, evidence from two trials, and reasoning to explain why prevention matters more than trying to fix unsafe handling later. FACS.2.COM.4
A supported claim links time, temperature, cooling, and reheating to two recorded trials. Explicitly separate the game's illustrative counts and permanent flag from real guidance; never use the game to decide whether actual food is safe.
Guidance for the teacher
Checked October 28, 2026. These sources describe real food handling guidance; the game is an illustrative model.