← Lemon juice invisible ink lesson New set →

Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 457 · 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.

NameDateTime takenScore ___ / 40
  1. 1.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is kept the same? (a) how dark the writing is (b) the iron setting (c) the kind of juice
  2. 2.🔮 Predict: the adult irons for only one second. What happens? (a) it gets darker (b) writing stays faint (c) the paper floats (d) writing turns green
  3. 3.🔮 Can the brown writing go back to being invisible? (a) no, it stays brown (b) yes, if shaken (c) yes, if cooled (d) yes, in the dark
  4. 4.🧺 Do we need a balloon for the secret lemon message? (a) needed (b) not needed
  5. 5.⚖️ 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
  6. 6.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) lemon juice (b) a mirror (c) a small bowl (d) white paper
  7. 7.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the iron setting is what we measure. (a) False (b) True
  8. 8.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a cotton bud (b) lemon juice (c) an adult with an iron (d) a magnet
  9. 9.🍋 Which of these steps is a job for an adult? (a) plugging in the iron (b) writing the message (c) dipping the cotton bud (d) letting the paper dry
  10. 10.True or false: cutting the lemon is a job a child can do. (a) False (b) True
  11. 11.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) lemon juice (b) white paper (c) a cotton bud (d) turmeric powder
  12. 12.⚖️ 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
  13. 13.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is what we measure? (a) the kind of juice (b) the same cotton bud (c) how dark the writing is (d) the same paper
  14. 14.🍋 Secret message: who does this step — putting the iron away? (a) an adult does it (b) a child can do it
  15. 15.🧺 Do we need an adult with an iron for the secret lemon message? (a) not needed (b) needed
  16. 16.🛟 Why must children keep their fingers away from the iron? (a) it can burn skin (b) it is sticky (c) it is cold (d) it is magnetic
  17. 17.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a small bowl (b) a cotton bud (c) a balloon (d) lemon juice
  18. 18.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is kept the same? (a) how dark the writing is (b) the ironing time (c) the kind of juice
  19. 19.🍋 Secret message: who does this step — writing the message? (a) a child can do it (b) an adult does it
  20. 20.🍋 Which of these steps is a job a child can do? (a) dipping the cotton bud (b) plugging in the iron (c) putting the iron away (d) cutting the lemon
  21. 21.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a small bowl (b) white paper (c) an adult with an iron (d) yeast
  22. 22.🔍 Which is the odd one out? (a) putting the iron away (b) dipping the cotton bud (c) cutting the lemon (d) ironing the paper
  23. 23.True or false: white paper is needed for the secret lemon message. (a) False (b) True
  24. 24.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the same cotton bud”? (a) we change it (b) we measure it (c) we keep it the same
  25. 25.🔍 Which is the odd one out? (a) reading the message (b) putting the iron away (c) letting the paper dry (d) writing the message
  26. 26.🍋 Secret message: who does this step — dipping the cotton bud? (a) a child can do it (b) an adult does it
  27. 27.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a cotton bud (b) lemon juice (c) a small bowl (d) a battery cell
  28. 28.⚖️ 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
  29. 29.🍋 What colour does the lemon writing turn when an adult warms it? (a) white (b) brown (c) blue (d) green
  30. 30.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: how dark the writing is is the one thing we change. (a) True (b) False
  31. 31.🧺 Which of these is needed for the secret lemon message? (a) a magnet (b) a balloon (c) a cotton bud (d) turmeric powder
  32. 32.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the same paper”? (a) we measure it (b) we change it (c) we keep it the same
  33. 33.🧺 Do we need yeast for the secret lemon message? (a) not needed (b) needed
  34. 34.True or false: yeast is not needed for the secret lemon message. (a) True (b) False
  35. 35.True or false: plugging in the iron is a job a child can do. (a) True (b) False
  36. 36.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: how dark the writing is is kept the same. (a) False (b) True
  37. 37.True or false: cutting the lemon is a job for an adult. (a) False (b) True
  38. 38.🔮 Predict: you write with plain water instead of lemon juice. What appears after ironing? (a) almost nothing (b) blue words (c) a rainbow (d) dark brown words
  39. 39.⚖️ 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 same cotton bud
  40. 40.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the same paper is kept the same. (a) False (b) True

Answer key

  1. the iron setting
  2. writing stays faint
  3. no, it stays brown
  4. not needed
  5. True
  6. a mirror
  7. False
  8. a magnet
  9. plugging in the iron
  10. False
  11. turmeric powder
  12. we measure it
  13. how dark the writing is
  14. an adult does it
  15. needed
  16. it can burn skin
  17. a balloon
  18. the ironing time
  19. a child can do it
  20. dipping the cotton bud
  21. yeast
  22. dipping the cotton bud
  23. True
  24. we keep it the same
  25. putting the iron away
  26. a child can do it
  27. a battery cell
  28. True
  29. brown
  30. False
  31. a cotton bud
  32. we keep it the same
  33. not needed
  34. True
  35. False
  36. False
  37. True
  38. almost nothing
  39. the same cotton bud
  40. True

Free science experiments lessons, practice and worksheets at talentjr.in/science-experiments-for-kids