Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 73 · 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 small bowl is not needed for the secret lemon message. (a) True (b) False
2. 2.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is the one thing we change? (a) the same cotton bud (b) the kind of juice (c) the same paper (d) the iron setting
3. 3.True or false: an adult with an iron is not needed for the secret lemon message. (a) False (b) True
4. 4.True or false: a cotton bud is not needed for the secret lemon message. (a) True (b) False
5. 5.🔍 Which is the odd one out? (a) letting the paper dry (b) writing the message (c) ironing the paper (d) reading the message
6. 6.True or false: white paper is not needed for the secret lemon message. (a) False (b) True
7. 7.True or false: turmeric powder is needed for the secret lemon message. (a) False (b) True
8. 8.⚖️ 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
9. 9.True or false: plugging in the iron is a job a child can do. (a) True (b) False
10. 10.⚖️ 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) True (b) False
11. 11.🍋 Why does the lemon writing turn brown with heat? (a) the juice scorches first (b) heat adds colour (c) the iron is brown (d) paper turns lemony
12. 12.🛟 Who should use the hot iron in the secret message experiment? (a) any child (b) the youngest child (c) whoever is fastest (d) only an adult
13. 13.🧺 Which of these is not needed for the secret lemon message? (a) a cotton bud (b) lemon juice (c) a balloon (d) an adult with an iron
14. 14.🔮 Can the brown writing go back to being invisible? (a) yes, if shaken (b) no, it stays brown (c) yes, in the dark (d) yes, if cooled
15. 15.🧺 Do we need lemon juice for the secret lemon message? (a) needed (b) not needed
16. 16.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a cotton bud (b) an adult with an iron (c) white paper (d) yeast
17. 17.🍋 Secret message: who does this step — letting the paper dry? (a) an adult does it (b) a child can do it
18. 18.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the same paper”? (a) we measure it (b) we change it (c) we keep it the same
19. 19.True or false: letting the paper dry is a job a child can do. (a) False (b) True
20. 20.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) skip washing (b) lick your fingers (c) wash your hands (d) rub your eyes
21. 21.⚖️ 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
22. 22.True or false: turmeric powder is not needed for the secret lemon message. (a) False (b) True
23. 23.⚖️ 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 same cotton bud
24. 24.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is what we measure? (a) the same cotton bud (b) the iron setting (c) the kind of juice (d) how dark the writing is
25. 25.True or false: ironing the paper is a job a child can do. (a) True (b) False
26. 26.🧺 Which of these is not needed for the secret lemon message? (a) white paper (b) turmeric powder (c) a cotton bud (d) an adult with an iron
27. 27.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a small bowl (b) a magnet (c) an adult with an iron (d) white paper
28. 28.🧺 Which of these is needed for the secret lemon message? (a) yeast (b) a small bowl (c) a mirror (d) turmeric powder
29. 29.🧺 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 balloon
30. 30.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the ironing time is the one thing we change. (a) False (b) True
31. 31.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the kind of juice is kept the same. (a) True (b) False
32. 32.🛟 Why must children keep their fingers away from the iron? (a) it is cold (b) it is magnetic (c) it can burn skin (d) it is sticky
33. 33.🧺 Which of these is needed for the secret lemon message? (a) a magnet (b) a mirror (c) a balloon (d) a cotton bud
34. 34.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) lemon juice (b) an adult with an iron (c) a mirror (d) a cotton bud
35. 35.🧺 Which of these is needed for the secret lemon message? (a) an adult with an iron (b) yeast (c) a battery cell (d) a magnet
36. 36.🍋 Secret message: who does this step — dipping the cotton bud? (a) an adult does it (b) a child can do it
37. 37.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the same cotton bud”? (a) we measure it (b) we change it (c) we keep it the same
38. 38.🍋 Secret message: who does this step — reading the message? (a) an adult does it (b) a child can do it
39. 39.True or false: reading the message is a job for an adult. (a) False (b) True
40. 40.🍋 Which of these steps is a job for an adult? (a) cutting the lemon (b) writing the message (c) dipping the cotton bud (d) letting the paper dry

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