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Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 16 · 40 questions
TalentJR

What you do (Heat shows the secret): 1. Dip a cotton bud in lemon juice and write a secret message on white paper. 2. Let the paper dry completely — the writing disappears. 3. An adult irons the paper on a low setting while you watch from a safe distance. 4. Read the brown message and wash your hands.

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  1. 1.True or false: an adult with an iron is not needed for the secret lemon message. (a) True (b) False
  2. 2.True or false: white paper is needed for the secret lemon message. (a) False (b) True
  3. 3.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) lemon juice (b) a balloon (c) a small bowl (d) a cotton bud
  4. 4.🧺 Which of these is needed for the secret lemon message? (a) a balloon (b) turmeric powder (c) a cotton bud (d) a magnet
  5. 5.🍋 Which of these steps is a job for an adult? (a) letting the paper dry (b) reading the message (c) putting the iron away (d) dipping the cotton bud
  6. 6.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a battery cell (b) a cotton bud (c) white paper (d) a small bowl
  7. 7.🧺 Which of these is not needed for the secret lemon message? (a) an adult with an iron (b) a magnet (c) a small bowl (d) lemon juice
  8. 8.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the ironing time is kept the same. (a) False (b) True
  9. 9.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a mirror (b) white paper (c) a cotton bud (d) an adult with an iron
  10. 10.True or false: dipping the cotton bud is a job for an adult. (a) True (b) False
  11. 11.True or false: a mirror is not needed for the secret lemon message. (a) True (b) False
  12. 12.🛟 Who should use the hot iron in the secret message experiment? (a) the youngest child (b) whoever is fastest (c) only an adult (d) any child
  13. 13.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) lick your fingers (b) rub your eyes (c) skip washing (d) wash your hands
  14. 14.🧺 Do we need an adult with an iron for the secret lemon message? (a) not needed (b) needed
  15. 15.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) turmeric powder (b) a small bowl (c) an adult with an iron (d) white paper
  16. 16.🔍 Which is the odd one out? (a) letting the paper dry (b) putting the iron away (c) dipping the cotton bud (d) writing the message
  17. 17.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a cotton bud (b) a small bowl (c) yeast (d) white paper
  18. 18.🧺 Which of these is needed for the secret lemon message? (a) a magnet (b) white paper (c) yeast (d) a mirror
  19. 19.🍋 Which of these steps is a job a child can do? (a) putting the iron away (b) ironing the paper (c) cutting the lemon (d) reading the message
  20. 20.🍋 Secret message: who does this step — writing the message? (a) a child can do it (b) an adult does it
  21. 21.🍋 Secret message: who does this step — ironing the paper? (a) a child can do it (b) an adult does it
  22. 22.🔍 Which is the odd one out? (a) ironing the paper (b) plugging in the iron (c) reading the message (d) putting the iron away
  23. 23.🔮 Predict: you write with plain water instead of lemon juice. What appears after ironing? (a) blue words (b) a rainbow (c) almost nothing (d) dark brown words
  24. 24.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a cotton bud (b) an adult with an iron (c) a small bowl (d) a magnet
  25. 25.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is what we measure? (a) the same paper (b) the ironing time (c) how dark the writing is (d) the same cotton bud
  26. 26.🛟 Why must children keep their fingers away from the iron? (a) it is cold (b) it can burn skin (c) it is magnetic (d) it is sticky
  27. 27.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is kept the same? (a) the kind of juice (b) how dark the writing is (c) the ironing time
  28. 28.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the iron setting”? (a) we keep it the same (b) we change it (c) we measure it
  29. 29.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the same paper is what we measure. (a) True (b) False
  30. 30.🍋 Secret message: who does this step — dipping the cotton bud? (a) an adult does it (b) a child can do it
  31. 31.🔍 Which is the odd one out? (a) letting the paper dry (b) reading the message (c) plugging in the iron (d) dipping the cotton bud
  32. 32.🍋 Which of these steps is a job a child can do? (a) putting the iron away (b) writing the message (c) cutting the lemon (d) ironing the paper
  33. 33.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “how dark the writing is”? (a) we change it (b) we keep it the same (c) we measure it
  34. 34.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the same paper”? (a) we keep it the same (b) we change it (c) we measure it
  35. 35.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the ironing time is the one thing we change. (a) True (b) False
  36. 36.🧺 Do we need a balloon for the secret lemon message? (a) not needed (b) needed
  37. 37.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the kind of juice”? (a) we measure it (b) we keep it the same (c) we change it
  38. 38.🍋 Which of these steps is a job for an adult? (a) ironing the paper (b) reading the message (c) letting the paper dry (d) writing the message
  39. 39.True or false: a mirror is needed for the secret lemon message. (a) False (b) True
  40. 40.🔍 Which is the odd one out? (a) letting the paper dry (b) dipping the cotton bud (c) writing the message (d) cutting the lemon

Answer key

  1. False
  2. True
  3. a balloon
  4. a cotton bud
  5. putting the iron away
  6. a battery cell
  7. a magnet
  8. True
  9. a mirror
  10. False
  11. True
  12. only an adult
  13. wash your hands
  14. needed
  15. turmeric powder
  16. putting the iron away
  17. yeast
  18. white paper
  19. reading the message
  20. a child can do it
  21. an adult does it
  22. reading the message
  23. almost nothing
  24. a magnet
  25. how dark the writing is
  26. it can burn skin
  27. the ironing time
  28. we keep it the same
  29. False
  30. a child can do it
  31. plugging in the iron
  32. writing the message
  33. we measure it
  34. we keep it the same
  35. False
  36. not needed
  37. we change it
  38. ironing the paper
  39. False
  40. cutting the lemon

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