Invisible Ink Experiment Worksheet

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

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