Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 874 · 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) ironing the paper (b) putting the iron away (c) letting the paper dry (d) cutting the lemon
2. 2.True or false: putting the iron away is a job a child can do. (a) True (b) False
3. 3.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the same paper is what we measure. (a) True (b) False
4. 4.🔮 Predict: you write with plain water instead of lemon juice. What appears after ironing? (a) blue words (b) dark brown words (c) almost nothing (d) a rainbow
5. 5.🔍 Which is the odd one out? (a) letting the paper dry (b) reading the message (c) ironing the paper (d) dipping the cotton bud
6. 6.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the same paper is kept the same. (a) False (b) True
7. 7.🍋 Which of these steps is a job a child can do? (a) ironing the paper (b) dipping the cotton bud (c) putting the iron away (d) plugging in the iron
8. 8.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the iron setting”? (a) we keep it the same (b) we measure it (c) we change it
9. 9.True or false: lemon juice is needed for the secret lemon message. (a) False (b) True
10. 10.🔮 Can the brown writing go back to being invisible? (a) no, it stays brown (b) yes, if cooled (c) yes, if shaken (d) yes, in the dark
11. 11.⚖️ 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
12. 12.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the ironing time”? (a) we measure it (b) we change it (c) we keep it the same
13. 13.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) wash your hands (b) lick your fingers (c) skip washing (d) rub your eyes
14. 14.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a cotton bud (b) a battery cell (c) a small bowl (d) lemon juice
15. 15.🧺 Which of these is not needed for the secret lemon message? (a) a cotton bud (b) lemon juice (c) yeast (d) an adult with an iron
16. 16.⚖️ 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 same paper (c) the kind of juice (d) how dark the writing is
17. 17.🧺 Which of these is needed for the secret lemon message? (a) lemon juice (b) a mirror (c) a magnet (d) yeast
18. 18.🧺 Which of these is needed for the secret lemon message? (a) a magnet (b) a cotton bud (c) a balloon (d) turmeric powder
19. 19.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the same cotton bud is kept the same. (a) True (b) False
20. 20.True or false: a cotton bud is needed for the secret lemon message. (a) False (b) True
21. 21.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a cotton bud (b) a small bowl (c) an adult with an iron (d) a magnet
22. 22.🧺 Which of these is not needed for the secret lemon message? (a) a cotton bud (b) a magnet (c) white paper (d) lemon juice
23. 23.🍋 Secret message: who does this step — putting the iron away? (a) a child can do it (b) an adult does it
24. 24.True or false: writing the message is a job for an adult. (a) True (b) False
25. 25.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is the one thing we change? (a) the kind of juice (b) the same cotton bud (c) the same paper (d) how dark the writing is
26. 26.🍋 What colour does the lemon writing turn when an adult warms it? (a) white (b) green (c) brown (d) blue
27. 27.🧺 Do we need a mirror for the secret lemon message? (a) needed (b) not needed
28. 28.🧺 Do we need a cotton bud for the secret lemon message? (a) needed (b) not needed
29. 29.🔮 Predict: the adult irons for only one second. What happens? (a) the paper floats (b) writing turns green (c) writing stays faint (d) it gets darker
30. 30.🧺 Do we need yeast for the secret lemon message? (a) needed (b) not needed
31. 31.🛟 Why must children keep their fingers away from the iron? (a) it can burn skin (b) it is cold (c) it is sticky (d) it is magnetic
32. 32.🍋 Which of these steps is a job for an adult? (a) letting the paper dry (b) dipping the cotton bud (c) writing the message (d) plugging in the iron
33. 33.True or false: an adult with an iron is not needed for the secret lemon message. (a) True (b) False
34. 34.⚖️ 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
35. 35.⚖️ 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
36. 36.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a small bowl (b) a cotton bud (c) lemon juice (d) yeast
37. 37.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the same cotton bud is the one thing we change. (a) False (b) True
38. 38.🧺 Which of these is not needed for the secret lemon message? (a) a battery cell (b) a cotton bud (c) an adult with an iron (d) white paper
39. 39.True or false: a magnet is not needed for the secret lemon message. (a) True (b) False
40. 40.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) white paper (b) a mirror (c) an adult with an iron (d) a cotton bud

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