Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 462 · 40 questions

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.

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

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