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Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 918 · 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.⚖️ 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 iron setting (c) how dark the writing is (d) the same cotton bud
  2. 2.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is the one thing we change? (a) the iron setting (b) the kind of juice (c) the ironing time (d) the same paper
  3. 3.🧺 Which of these is needed for the secret lemon message? (a) a magnet (b) a battery cell (c) turmeric powder (d) a cotton bud
  4. 4.True or false: turmeric powder is not needed for the secret lemon message. (a) True (b) False
  5. 5.⚖️ 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) the same paper (c) how dark the writing is
  6. 6.True or false: turmeric powder is needed for the secret lemon message. (a) False (b) True
  7. 7.🧺 Which of these is not needed for the secret lemon message? (a) a mirror (b) white paper (c) a cotton bud (d) lemon juice
  8. 8.🧺 Do we need an adult with an iron for the secret lemon message? (a) not needed (b) needed
  9. 9.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) lemon juice (b) a cotton bud (c) a balloon (d) white paper
  10. 10.True or false: reading the message is a job for an adult. (a) True (b) False
  11. 11.🍋 Which of these steps is a job for an adult? (a) letting the paper dry (b) writing the message (c) dipping the cotton bud (d) putting the iron away
  12. 12.🍋 Which of these steps is a job a child can do? (a) plugging in the iron (b) reading the message (c) ironing the paper (d) cutting the lemon
  13. 13.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the ironing time”? (a) we measure it (b) we keep it the same (c) we change it
  14. 14.🛟 Why must children keep their fingers away from the iron? (a) it is magnetic (b) it is cold (c) it is sticky (d) it can burn skin
  15. 15.🍋 Which of these steps is a job for an adult? (a) reading the message (b) letting the paper dry (c) plugging in the iron (d) writing the message
  16. 16.🍋 Secret message: who does this step — dipping the cotton bud? (a) a child can do it (b) an adult does it
  17. 17.🔍 Which is the odd one out? (a) ironing the paper (b) dipping the cotton bud (c) reading the message (d) letting the paper dry
  18. 18.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a cotton bud (b) a battery cell (c) a small bowl (d) lemon juice
  19. 19.🔮 Predict: you write with plain water instead of lemon juice. What appears after ironing? (a) a rainbow (b) blue words (c) almost nothing (d) dark brown words
  20. 20.🍋 Which of these steps is a job for an adult? (a) writing the message (b) cutting the lemon (c) dipping the cotton bud (d) letting the paper dry
  21. 21.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: how dark the writing is is what we measure. (a) False (b) True
  22. 22.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “how dark the writing is”? (a) we keep it the same (b) we measure it (c) we change it
  23. 23.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the kind of juice is the one thing we change. (a) True (b) False
  24. 24.🔮 Predict: the adult irons for only one second. What happens? (a) writing turns green (b) writing stays faint (c) the paper floats (d) it gets darker
  25. 25.🍋 What colour does the lemon writing turn when an adult warms it? (a) green (b) brown (c) white (d) blue
  26. 26.True or false: plugging in the iron is a job a child can do. (a) False (b) True
  27. 27.🍋 Why can’t you see the lemon writing once it dries? (a) dry juice is see-through (b) the ink is magnetic (c) it turned into air (d) the paper ate it
  28. 28.🧺 Which of these is not needed for the secret lemon message? (a) an adult with an iron (b) turmeric powder (c) white paper (d) lemon juice
  29. 29.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the ironing time is kept the same. (a) True (b) False
  30. 30.🧺 Which of these is needed for the secret lemon message? (a) a battery cell (b) turmeric powder (c) white paper (d) yeast
  31. 31.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the same cotton bud is kept the same. (a) False (b) True
  32. 32.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) yeast (b) lemon juice (c) an adult with an iron (d) white paper
  33. 33.🧺 Do we need lemon juice for the secret lemon message? (a) not needed (b) needed
  34. 34.🔍 Which is the odd one out? (a) plugging in the iron (b) ironing the paper (c) letting the paper dry (d) putting the iron away
  35. 35.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a cotton bud (b) a small bowl (c) turmeric powder (d) white paper
  36. 36.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the same paper is the one thing we change. (a) False (b) True
  37. 37.True or false: an adult with an iron is needed for the secret lemon message. (a) True (b) False
  38. 38.True or false: a magnet is not needed for the secret lemon message. (a) False (b) True
  39. 39.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the iron setting”? (a) we measure it (b) we change it (c) we keep it the same
  40. 40.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the iron setting is the one thing we change. (a) False (b) True

Answer key

  1. how dark the writing is
  2. the kind of juice
  3. a cotton bud
  4. True
  5. the same paper
  6. False
  7. a mirror
  8. needed
  9. a balloon
  10. False
  11. putting the iron away
  12. reading the message
  13. we keep it the same
  14. it can burn skin
  15. plugging in the iron
  16. a child can do it
  17. ironing the paper
  18. a battery cell
  19. almost nothing
  20. cutting the lemon
  21. True
  22. we measure it
  23. True
  24. writing stays faint
  25. brown
  26. False
  27. dry juice is see-through
  28. turmeric powder
  29. True
  30. white paper
  31. True
  32. yeast
  33. needed
  34. letting the paper dry
  35. turmeric powder
  36. False
  37. True
  38. True
  39. we keep it the same
  40. False

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