Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 559 · 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) reading the message (b) dipping the cotton bud (c) letting the paper dry (d) putting the iron away
2. 2.🍋 Why can’t you see the lemon writing once it dries? (a) it turned into air (b) the ink is magnetic (c) dry juice is see-through (d) the paper ate it
3. 3.True or false: white paper is needed for the secret lemon message. (a) True (b) False
4. 4.🍋 Secret message: who does this step — ironing the paper? (a) an adult does it (b) a child can do it
5. 5.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) rub your eyes (b) skip washing (c) lick your fingers (d) wash your hands
6. 6.🧺 Which of these is not needed for the secret lemon message? (a) lemon juice (b) white paper (c) turmeric powder (d) a small bowl
7. 7.🛟 Why must children keep their fingers away from the iron? (a) it is magnetic (b) it is cold (c) it can burn skin (d) it is sticky
8. 8.🧺 Do we need a small bowl for the secret lemon message? (a) needed (b) not needed
9. 9.🍋 Secret message: who does this step — dipping the cotton bud? (a) an adult does it (b) a child can do it
10. 10.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is kept the same? (a) the kind of juice (b) how dark the writing is (c) the same cotton bud
11. 11.🔍 Which is the odd one out? (a) ironing the paper (b) dipping the cotton bud (c) cutting the lemon (d) plugging in the iron
12. 12.🧺 Which of these is needed for the secret lemon message? (a) a magnet (b) a mirror (c) yeast (d) a cotton bud
13. 13.🧺 Which of these is not needed for the secret lemon message? (a) a small bowl (b) lemon juice (c) a cotton bud (d) a balloon
14. 14.⚖️ 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 kind of juice (c) how dark the writing is (d) the same cotton bud
15. 15.🛟 Who should use the hot iron in the secret message experiment? (a) whoever is fastest (b) any child (c) the youngest child (d) only an adult
16. 16.⚖️ 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
17. 17.⚖️ 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
18. 18.🍋 Which of these steps is a job a child can do? (a) dipping the cotton bud (b) ironing the paper (c) putting the iron away (d) cutting the lemon
19. 19.🍋 Which of these steps is a job for an adult? (a) letting the paper dry (b) dipping the cotton bud (c) putting the iron away (d) writing the message
20. 20.True or false: putting the iron away is a job a child can do. (a) False (b) True
21. 21.⚖️ 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) how dark the writing is (c) the same paper (d) the kind of juice
22. 22.🧺 Which of these is needed for the secret lemon message? (a) a small bowl (b) a magnet (c) a balloon (d) yeast
23. 23.True or false: white paper is not needed for the secret lemon message. (a) True (b) False
24. 24.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a battery cell (b) white paper (c) lemon juice (d) a small bowl
25. 25.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a small bowl (b) a balloon (c) lemon juice (d) an adult with an iron
26. 26.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the same cotton bud is what we measure. (a) True (b) False
27. 27.⚖️ 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
28. 28.🧺 Do we need a magnet for the secret lemon message? (a) not needed (b) needed
29. 29.🍋 Why does the lemon writing turn brown with heat? (a) the iron is brown (b) the juice scorches first (c) heat adds colour (d) paper turns lemony
30. 30.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the iron setting is the one thing we change. (a) True (b) False
31. 31.🧺 Do we need a cotton bud for the secret lemon message? (a) not needed (b) needed
32. 32.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “how dark the writing is”? (a) we keep it the same (b) we measure it (c) we change it
33. 33.🍋 Secret message: who does this step — putting the iron away? (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? What do we do with “the same cotton bud”? (a) we measure it (b) we keep it the same (c) we change it
35. 35.True or false: ironing the paper is a job a child can do. (a) True (b) False
36. 36.🍋 Which of these steps is a job for an adult? (a) plugging in the iron (b) dipping the cotton bud (c) writing the message (d) letting the paper dry
37. 37.True or false: writing the message is a job for an adult. (a) True (b) False
38. 38.🧺 Do we need white paper for the secret lemon message? (a) not needed (b) needed
39. 39.🔍 Which is the odd one out? (a) ironing the paper (b) putting the iron away (c) plugging in the iron (d) writing the message
40. 40.🧺 Which of these is not needed for the secret lemon message? (a) a small bowl (b) lemon juice (c) a battery cell (d) a cotton bud

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