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Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 86 · 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: writing the message is a job a child can do. (a) False (b) True
  2. 2.🛟 Why must children keep their fingers away from the iron? (a) it is sticky (b) it is cold (c) it is magnetic (d) it can burn skin
  3. 3.🍋 Which of these steps is a job for an adult? (a) letting the paper dry (b) cutting the lemon (c) dipping the cotton bud (d) reading the message
  4. 4.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is what we measure? (a) how dark the writing is (b) the same cotton bud (c) the iron setting (d) the kind of juice
  5. 5.🍋 Secret message: who does this step — dipping the cotton bud? (a) a child can do it (b) an adult does it
  6. 6.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is the one thing we change? (a) the kind of juice (b) the same paper (c) the ironing time (d) how dark the writing is
  7. 7.🧺 Do we need a mirror for the secret lemon message? (a) not needed (b) needed
  8. 8.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) yeast (b) lemon juice (c) a cotton bud (d) an adult with an iron
  9. 9.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the same cotton bud is kept the same. (a) True (b) False
  10. 10.🍋 Secret message: who does this step — putting the iron away? (a) a child can do it (b) an adult does it
  11. 11.🍋 Secret message: who does this step — writing the message? (a) a child can do it (b) an adult does it
  12. 12.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the kind of juice is kept the same. (a) True (b) False
  13. 13.🍋 What colour does the lemon writing turn when an adult warms it? (a) brown (b) white (c) green (d) blue
  14. 14.🔍 Which is the odd one out? (a) plugging in the iron (b) writing the message (c) ironing the paper (d) putting the iron away
  15. 15.🔮 Predict: the adult irons for only one second. What happens? (a) writing turns green (b) it gets darker (c) writing stays faint (d) the paper floats
  16. 16.🔍 Which is the odd one out? (a) putting the iron away (b) dipping the cotton bud (c) letting the paper dry (d) reading the message
  17. 17.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) lemon juice (b) an adult with an iron (c) a balloon (d) white paper
  18. 18.⚖️ 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 change it (c) we measure it
  19. 19.🧺 Do we need yeast for the secret lemon message? (a) needed (b) not needed
  20. 20.🧺 Which of these is needed for the secret lemon message? (a) a mirror (b) a balloon (c) a magnet (d) a small bowl
  21. 21.🛟 Who should use the hot iron in the secret message experiment? (a) whoever is fastest (b) any child (c) the youngest child (d) only an adult
  22. 22.🔍 Which is the odd one out? (a) ironing the paper (b) cutting the lemon (c) plugging in the iron (d) reading the message
  23. 23.🍋 Why does the lemon writing turn brown with heat? (a) paper turns lemony (b) heat adds colour (c) the iron is brown (d) the juice scorches first
  24. 24.🍋 Which of these steps is a job a child can do? (a) writing the message (b) putting the iron away (c) ironing the paper (d) cutting the lemon
  25. 25.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is kept the same? (a) the same paper (b) the kind of juice (c) how dark the writing is
  26. 26.🍋 Which of these steps is a job a child can do? (a) cutting the lemon (b) plugging in the iron (c) reading the message (d) putting the iron away
  27. 27.🧺 Which of these is needed for the secret lemon message? (a) a magnet (b) an adult with an iron (c) a balloon (d) turmeric powder
  28. 28.🔍 Which is the odd one out? (a) reading the message (b) plugging in the iron (c) dipping the cotton bud (d) writing the message
  29. 29.🍋 Secret message: who does this step — plugging in the iron? (a) an adult does it (b) a child can do it
  30. 30.⚖️ 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) True (b) False
  31. 31.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the ironing time”? (a) we keep it the same (b) we measure it (c) we change it
  32. 32.True or false: lemon juice is not needed for the secret lemon message. (a) True (b) False
  33. 33.🍋 Secret message: who does this step — letting the paper dry? (a) a child can do it (b) an adult does it
  34. 34.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) lick your fingers (b) rub your eyes (c) wash your hands (d) skip washing
  35. 35.🍋 Which of these steps is a job a child can do? (a) cutting the lemon (b) plugging in the iron (c) letting the paper dry (d) putting the iron away
  36. 36.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) an adult with an iron (b) lemon juice (c) white paper (d) a mirror
  37. 37.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) lemon juice (b) a small bowl (c) a battery cell (d) a cotton bud
  38. 38.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the iron setting”? (a) we change it (b) we keep it the same (c) we measure it
  39. 39.🧺 Do we need a small bowl for the secret lemon message? (a) not needed (b) needed
  40. 40.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the kind of juice”? (a) we change it (b) we keep it the same (c) we measure it

Answer key

  1. True
  2. it can burn skin
  3. cutting the lemon
  4. how dark the writing is
  5. a child can do it
  6. the kind of juice
  7. not needed
  8. yeast
  9. True
  10. an adult does it
  11. a child can do it
  12. False
  13. brown
  14. writing the message
  15. writing stays faint
  16. putting the iron away
  17. a balloon
  18. we measure it
  19. not needed
  20. a small bowl
  21. only an adult
  22. reading the message
  23. the juice scorches first
  24. writing the message
  25. the same paper
  26. reading the message
  27. an adult with an iron
  28. plugging in the iron
  29. an adult does it
  30. False
  31. we keep it the same
  32. False
  33. a child can do it
  34. wash your hands
  35. letting the paper dry
  36. a mirror
  37. a battery cell
  38. we keep it the same
  39. needed
  40. we change it

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