Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 777 · 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.True or false: putting the iron away is a job for an adult. (a) False (b) True
2. 2.🧺 Do we need a magnet for the secret lemon message? (a) needed (b) not needed
3. 3.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a small bowl (b) a mirror (c) white paper (d) lemon juice
4. 4.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the same paper is kept the same. (a) True (b) False
5. 5.🔍 Which is the odd one out? (a) dipping the cotton bud (b) plugging in the iron (c) cutting the lemon (d) putting the iron away
6. 6.🧺 Do we need turmeric powder for the secret lemon message? (a) needed (b) not needed
7. 7.🧺 Do we need a small bowl for the secret lemon message? (a) not needed (b) needed
8. 8.🧺 Which of these is not needed for the secret lemon message? (a) white paper (b) a small bowl (c) a battery cell (d) lemon juice
9. 9.⚖️ 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) False (b) True
10. 10.True or false: dipping the cotton bud is a job a child can do. (a) False (b) True
11. 11.🔍 Which is the odd one out? (a) putting the iron away (b) plugging in the iron (c) ironing the paper (d) writing the message
12. 12.🛟 Why must children keep their fingers away from the iron? (a) it can burn skin (b) it is magnetic (c) it is cold (d) it is sticky
13. 13.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the iron setting”? (a) we measure it (b) we keep it the same (c) we change it
14. 14.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) lemon juice (b) a cotton bud (c) a small bowl (d) a magnet
15. 15.True or false: a small bowl is needed for the secret lemon message. (a) False (b) True
16. 16.True or false: lemon juice is needed for the secret lemon message. (a) True (b) False
17. 17.🧺 Do we need a cotton bud for the secret lemon message? (a) needed (b) not needed
18. 18.⚖️ 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 measure it (c) we keep it the same
19. 19.🧺 Do we need an adult with an iron for the secret lemon message? (a) not needed (b) needed
20. 20.🍋 Secret message: who does this step — writing the message? (a) a child can do it (b) an adult does it
21. 21.🍋 Why does the lemon writing turn brown with heat? (a) the iron is brown (b) paper turns lemony (c) heat adds colour (d) the juice scorches first
22. 22.True or false: letting the paper dry is a job a child can do. (a) False (b) True
23. 23.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the kind of juice is what we measure. (a) False (b) True
24. 24.🔍 Which is the odd one out? (a) reading the message (b) letting the paper dry (c) dipping the cotton bud (d) plugging in the iron
25. 25.⚖️ 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 measure it (c) we keep it the same
26. 26.True or false: a battery cell is needed for the secret lemon message. (a) True (b) False
27. 27.🧺 Do we need yeast for the secret lemon message? (a) needed (b) not needed
28. 28.True or false: cutting the lemon is a job for an adult. (a) False (b) True
29. 29.🧺 Do we need a mirror for the secret lemon message? (a) needed (b) not needed
30. 30.🍋 Why can’t you see the lemon writing once it dries? (a) it turned into air (b) dry juice is see-through (c) the paper ate it (d) the ink is magnetic
31. 31.🍋 Which of these steps is a job for an adult? (a) writing the message (b) dipping the cotton bud (c) plugging in the iron (d) letting the paper dry
32. 32.🧺 Which of these is not needed for the secret lemon message? (a) a magnet (b) white paper (c) a small bowl (d) an adult with an iron
33. 33.🧺 Which of these is needed for the secret lemon message? (a) a battery cell (b) yeast (c) a small bowl (d) a balloon
34. 34.🍋 Secret message: who does this step — plugging in the iron? (a) a child can do it (b) an adult does it
35. 35.🧺 Which of these is needed for the secret lemon message? (a) lemon juice (b) a battery cell (c) turmeric powder (d) yeast
36. 36.🧺 Which of these is not needed for the secret lemon message? (a) white paper (b) lemon juice (c) turmeric powder (d) an adult with an iron
37. 37.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is kept the same? (a) the same cotton bud (b) how dark the writing is (c) the kind of juice
38. 38.True or false: white paper is needed for the secret lemon message. (a) False (b) True
39. 39.⚖️ 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
40. 40.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) yeast (b) lemon juice (c) an adult with an iron (d) a cotton bud

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