{"id":"study-packets-postcard-analogy","audience":"high-school","category":"explaining","technique":"audience","track":"study","title":"Explain how internet packets travel using a postcard analogy","free":false,"task":"Your AP Computer Science Principles exam has a written question on how data travels across the internet. Get exactly 3 numbered sentences using only Mr. Tsai's postcard analogy (splitting a message into packets, packets taking different routes, putting them back in order), then one line starting 'Check:' with a question to test yourself, under 75 words, plain text. No code and none of the terms TCP/IP, router table or checksum.","materialLabel":"Your AP CSP notes (attached to your prompt automatically)","material":"AP CSP - Mr. Tsai - Unit 4: The Internet\n\nPACKETS: Data sent over the internet is broken into small chunks called packets.\n\nMR. TSAI'S POSTCARD ANALOGY:\n- Imagine mailing a long letter, but the post office only takes postcards. You cut your letter into 20 postcards and number each one.\n- Each postcard can go by a different mail truck and route, depending on traffic.\n- Postcards may arrive out of order. Your friend uses the numbers to put the letter back together.\n- If one postcard goes missing, your friend asks you to resend just that one.\n\nExam question (from the practice exam): \"Explain in plain language how a large file is sent across the internet.\"\nMr. Tsai: \"No acronyms. If you write TCP/IP without explaining it, you get zero.\"\n\nWords in the textbook we're NOT using: TCP/IP, router table, checksum, latency.\n\nMy confusion: why don't all the packets just take the same path?\n\nCreate Performance Task due in 3 weeks. Practice exam Friday.","rules":[{"type":"numberedItems","count":3},{"type":"maxWords","max":75},{"type":"plainText"}],"mistakes":[{"title":"Asking the general question","why":"The AI explains with technical terms like TCP/IP, which your teacher said earns zero without explanation.","fix":"Say: \"Use only the postcard analogy from my notes.\"","checks":["r0"]},{"title":"Not saying how many sentences","why":"The AI picks its own number, and it usually picks more sentences than you need.","fix":"Be exact: \"Exactly 3 numbered sentences.\"","checks":["numberedItems"]},{"title":"Not banning jargon","why":"AI defaults to networking acronyms.","fix":"Add: \"No TCP/IP, router table, checksum or latency.\"","checks":["r1"]},{"title":"No way to test yourself","why":"The AI explains and stops, so you never check whether it stuck.","fix":"Add: \"End with one line starting 'Check:' with a question, no answer.\"","checks":["r2"]},{"title":"Trusting the AI to count words","why":"AI is bad at counting. Ask for a total and it often lands 20% over.","fix":"Cap each sentence: \"each under 18 words.\"","checks":["maxWords"]},{"title":"Forgetting where it will be read","why":"AI formats for a screen, with bold and headings that show up as stray symbols on the exam.","fix":"Say: \"Plain text, no bold, no headings.\"","checks":["plainText"]}],"promptHints":[{"label":"Names the analogy","patterns":["postcard"]},{"label":"Says how many sentences","patterns":["\\b(3|three)\\b.{0,25}sentence"]},{"label":"Bans jargon","patterns":["tcp","acronym","jargon","checksum"]},{"label":"Asks for a check question","patterns":["check:","check question","test (me|myself)","quiz me"]},{"label":"Sets a length limit","patterns":["\\d+\\s*words","word (limit|count)","under \\d+"]}],"hint":"Tell the AI the analogy, the three ideas to cover, the words to keep out, and that you want a question to test yourself at the end.","rubricLabels":["Uses only the postcard analogy to explain three ideas: the message is split into numbered packets, packets can take different routes, and the numbers let them be put back in order","Contains no code and none of the terms TCP/IP, router table, checksum or latency","Ends with one line starting 'Check:' that asks a question about packets, and does not answer it"]}