Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 927 · 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.🔍 Which is the odd one out? (a) plugging in the iron (b) cutting the lemon (c) dipping the cotton bud (d) putting the iron away
2. 2.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) wash your hands (b) lick your fingers (c) rub your eyes (d) skip washing
3. 3.True or false: plugging in the iron is a job for an adult. (a) True (b) False
4. 4.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a small bowl (b) white paper (c) a balloon (d) an adult with an iron
5. 5.🛟 Who should use the hot iron in the secret message experiment? (a) the youngest child (b) any child (c) only an adult (d) whoever is fastest
6. 6.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a small bowl (b) a magnet (c) lemon juice (d) an adult with an iron
7. 7.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the kind of juice”? (a) we keep it the same (b) we measure it (c) we change it
8. 8.🍋 Why can’t you see the lemon writing once it dries? (a) the ink is magnetic (b) it turned into air (c) dry juice is see-through (d) the paper ate it
9. 9.🛟 Why must children keep their fingers away from the iron? (a) it can burn skin (b) it is magnetic (c) it is sticky (d) it is cold
10. 10.🍋 Secret message: who does this step — letting the paper dry? (a) an adult does it (b) a child can do it
11. 11.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is the one thing we change? (a) the ironing time (b) the iron setting (c) the kind of juice (d) how dark the writing is
12. 12.🍋 Which of these steps is a job for an adult? (a) dipping the cotton bud (b) reading the message (c) ironing the paper (d) writing the message
13. 13.🔍 Which is the odd one out? (a) ironing the paper (b) plugging in the iron (c) letting the paper dry (d) cutting the lemon
14. 14.🧺 Which of these is needed for the secret lemon message? (a) turmeric powder (b) a balloon (c) a battery cell (d) a cotton bud
15. 15.🔮 Predict: you write with plain water instead of lemon juice. What appears after ironing? (a) dark brown words (b) almost nothing (c) blue words (d) a rainbow
16. 16.🧺 Do we need yeast for the secret lemon message? (a) not needed (b) needed
17. 17.True or false: a mirror is not needed for the secret lemon message. (a) False (b) True
18. 18.True or false: reading the message is a job a child can do. (a) False (b) True
19. 19.True or false: turmeric powder is not needed for the secret lemon message. (a) True (b) False
20. 20.True or false: dipping the cotton bud is a job a child can do. (a) True (b) False
21. 21.True or false: a magnet is needed for the secret lemon message. (a) True (b) False
22. 22.🧺 Do we need an adult with an iron for the secret lemon message? (a) not needed (b) needed
23. 23.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the same paper”? (a) we change it (b) we keep it the same (c) we measure it
24. 24.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is what we measure? (a) the ironing time (b) how dark the writing is (c) the same cotton bud (d) the same paper
25. 25.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) turmeric powder (b) white paper (c) lemon juice (d) an adult with an iron
26. 26.True or false: putting the iron away is a job a child can do. (a) False (b) True
27. 27.🧺 Do we need a balloon for the secret lemon message? (a) not needed (b) needed
28. 28.🔍 Which is the odd one out? (a) cutting the lemon (b) dipping the cotton bud (c) writing the message (d) reading the message
29. 29.🔮 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
30. 30.⚖️ 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 kind of juice (c) the ironing time
31. 31.True or false: white paper is needed for the secret lemon message. (a) True (b) False
32. 32.🧺 Which of these is needed for the secret lemon message? (a) turmeric powder (b) a balloon (c) lemon juice (d) a battery cell
33. 33.🍋 Secret message: who does this step — ironing the paper? (a) a child can do it (b) an adult does it
34. 34.⚖️ 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 same cotton bud (c) the kind of juice
35. 35.True or false: writing the message is a job for an adult. (a) True (b) False
36. 36.⚖️ 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 change it (c) we measure it
37. 37.🧺 Do we need lemon juice for the secret lemon message? (a) not needed (b) needed
38. 38.🧺 Which of these is needed for the secret lemon message? (a) yeast (b) a battery cell (c) a small bowl (d) turmeric powder
39. 39.True or false: white paper is not needed for the secret lemon message. (a) True (b) False
40. 40.🧺 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

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