Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 988 · 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: a mirror is not needed for the secret lemon message. (a) True (b) False
2. 2.🍋 Which of these steps is a job a child can do? (a) plugging in the iron (b) ironing the paper (c) cutting the lemon (d) dipping the cotton bud
3. 3.⚖️ 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
4. 4.🧺 Do we need a small bowl for the secret lemon message? (a) not needed (b) needed
5. 5.🧺 Which of these is needed for the secret lemon message? (a) an adult with an iron (b) a battery cell (c) a mirror (d) a magnet
6. 6.⚖️ 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 measure it (c) we change it
7. 7.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: how dark the writing is is what we measure. (a) True (b) False
8. 8.🔍 Which is the odd one out? (a) putting the iron away (b) reading the message (c) plugging in the iron (d) cutting the lemon
9. 9.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) turmeric powder (b) a small bowl (c) an adult with an iron (d) lemon juice
10. 10.🔮 Can the brown writing go back to being invisible? (a) no, it stays brown (b) yes, if shaken (c) yes, in the dark (d) yes, if cooled
11. 11.🍋 Which of these steps is a job for an adult? (a) letting the paper dry (b) putting the iron away (c) dipping the cotton bud (d) writing the message
12. 12.True or false: a magnet is needed for the secret lemon message. (a) False (b) True
13. 13.🛟 Who should use the hot iron in the secret message experiment? (a) whoever is fastest (b) only an adult (c) any child (d) the youngest child
14. 14.True or false: white paper is needed for the secret lemon message. (a) False (b) True
15. 15.🧺 Do we need a mirror for the secret lemon message? (a) not needed (b) needed
16. 16.⚖️ 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) True (b) False
17. 17.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is what we measure? (a) the iron setting (b) the kind of juice (c) the same paper (d) how dark the writing is
18. 18.True or false: plugging in the iron is a job a child can do. (a) True (b) False
19. 19.🧺 Which of these is needed for the secret lemon message? (a) turmeric powder (b) a battery cell (c) a cotton bud (d) yeast
20. 20.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) white paper (b) a cotton bud (c) lemon juice (d) a battery cell
21. 21.🔮 Predict: you write with plain water instead of lemon juice. What appears after ironing? (a) a rainbow (b) blue words (c) dark brown words (d) almost nothing
22. 22.🔍 Which is the odd one out? (a) cutting the lemon (b) ironing the paper (c) plugging in the iron (d) writing the message
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 measure it (c) we keep it the same
24. 24.True or false: a small bowl is not needed for the secret lemon message. (a) False (b) True
25. 25.🍋 Why can’t you see the lemon writing once it dries? (a) dry juice is see-through (b) the paper ate it (c) the ink is magnetic (d) it turned into air
26. 26.True or false: a battery cell is not needed for the secret lemon message. (a) False (b) True
27. 27.🍋 Why does the lemon writing turn brown with heat? (a) heat adds colour (b) paper turns lemony (c) the iron is brown (d) the juice scorches first
28. 28.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is the one thing we change? (a) the iron setting (b) the same cotton bud (c) the kind of juice (d) the ironing time
29. 29.True or false: a battery cell is needed for the secret lemon message. (a) False (b) True
30. 30.🔍 Which is the odd one out? (a) reading the message (b) cutting the lemon (c) dipping the cotton bud (d) writing the message
31. 31.🍋 Which of these steps is a job for an adult? (a) dipping the cotton bud (b) cutting the lemon (c) reading the message (d) writing the message
32. 32.True or false: lemon juice is not needed for the secret lemon message. (a) False (b) True
33. 33.True or false: writing the message is a job a child can do. (a) False (b) True
34. 34.🧺 Which of these is needed for the secret lemon message? (a) a balloon (b) turmeric powder (c) a battery cell (d) a small bowl
35. 35.🧺 Which of these is not needed for the secret lemon message? (a) lemon juice (b) an adult with an iron (c) white paper (d) a magnet
36. 36.🍋 Secret message: who does this step — cutting the lemon? (a) a child can do it (b) an adult does it
37. 37.🛟 Why must children keep their fingers away from the iron? (a) it is sticky (b) it is magnetic (c) it is cold (d) it can burn skin
38. 38.True or false: reading the message is a job for an adult. (a) True (b) False
39. 39.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a balloon (b) lemon juice (c) an adult with an iron (d) white paper
40. 40.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the iron setting”? (a) we change it (b) we keep it the same (c) we measure it

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