Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 884 · 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.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a cotton bud (b) white paper (c) a small bowl (d) yeast
2. 2.🔮 Predict: the adult irons for only one second. What happens? (a) it gets darker (b) the paper floats (c) writing turns green (d) writing stays faint
3. 3.🧺 Do we need an adult with an iron for the secret lemon message? (a) not needed (b) needed
4. 4.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the same paper”? (a) we keep it the same (b) we measure it (c) we change it
5. 5.🧺 Do we need yeast for the secret lemon message? (a) not needed (b) needed
6. 6.True or false: writing the message is a job for an adult. (a) True (b) False
7. 7.True or false: plugging in the iron is a job for an adult. (a) True (b) False
8. 8.⚖️ 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 measure it (c) we keep it the same
9. 9.🍋 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
10. 10.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a mirror (b) a cotton bud (c) an adult with an iron (d) white paper
11. 11.🧺 Which of these is needed for the secret lemon message? (a) a balloon (b) a battery cell (c) a magnet (d) an adult with an iron
12. 12.🍋 What colour does the lemon writing turn when an adult warms it? (a) white (b) blue (c) brown (d) green
13. 13.🔮 Can the brown writing go back to being invisible? (a) yes, in the dark (b) no, it stays brown (c) yes, if shaken (d) yes, if cooled
14. 14.True or false: letting the paper dry is a job a child can do. (a) True (b) False
15. 15.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) skip washing (b) lick your fingers (c) rub your eyes (d) wash your hands
16. 16.⚖️ 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
17. 17.🔍 Which is the odd one out? (a) dipping the cotton bud (b) letting the paper dry (c) reading the message (d) plugging in the iron
18. 18.🔍 Which is the odd one out? (a) plugging in the iron (b) reading the message (c) ironing the paper (d) cutting the lemon
19. 19.True or false: a cotton bud is not needed for the secret lemon message. (a) True (b) False
20. 20.True or false: yeast is needed for the secret lemon message. (a) True (b) False
21. 21.🍋 Secret message: who does this step — writing the message? (a) an adult does it (b) a child can do it
22. 22.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is the one thing we change? (a) the same paper (b) the ironing time (c) how dark the writing is (d) the kind of juice
23. 23.⚖️ 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
24. 24.True or false: dipping the cotton bud is a job for an adult. (a) False (b) True
25. 25.🛟 Who should use the hot iron in the secret message experiment? (a) any child (b) only an adult (c) the youngest child (d) whoever is fastest
26. 26.🧺 Which of these is needed for the secret lemon message? (a) a mirror (b) a balloon (c) yeast (d) lemon juice
27. 27.🔮 Predict: you write with plain water instead of lemon juice. What appears after ironing? (a) a rainbow (b) dark brown words (c) almost nothing (d) blue words
28. 28.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the same paper is the one thing we change. (a) False (b) True
29. 29.🍋 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
30. 30.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the ironing time”? (a) we change it (b) we measure it (c) we keep it the same
31. 31.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) an adult with an iron (b) a small bowl (c) white paper (d) a balloon
32. 32.⚖️ 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) False (b) True
33. 33.True or false: putting the iron away is a job for an adult. (a) True (b) False
34. 34.🧺 Which of these is not needed for the secret lemon message? (a) an adult with an iron (b) lemon juice (c) white paper (d) yeast
35. 35.True or false: writing the message is a job a child can do. (a) False (b) True
36. 36.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a small bowl (b) white paper (c) a cotton bud (d) a magnet
37. 37.🧺 Which of these is not needed for the secret lemon message? (a) an adult with an iron (b) lemon juice (c) a battery cell (d) a cotton bud
38. 38.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a small bowl (b) lemon juice (c) a cotton bud (d) turmeric powder
39. 39.🧺 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) an adult with an iron
40. 40.🧺 Which of these is not needed for the secret lemon message? (a) a cotton bud (b) white paper (c) a small bowl (d) a balloon

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