Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 248 · 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 of these steps is a job a child can do? (a) putting the iron away (b) reading the message (c) plugging in the iron (d) ironing the paper
2. 2.🛟 Who should use the hot iron in the secret message experiment? (a) only an adult (b) the youngest child (c) whoever is fastest (d) any child
3. 3.🧺 Do we need a magnet for the secret lemon message? (a) needed (b) not needed
4. 4.🍋 Which of these steps is a job a child can do? (a) ironing the paper (b) plugging in the iron (c) putting the iron away (d) writing the message
5. 5.🔮 Predict: you write with plain water instead of lemon juice. What appears after ironing? (a) dark brown words (b) blue words (c) almost nothing (d) a rainbow
6. 6.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) white paper (b) a cotton bud (c) a mirror (d) lemon juice
7. 7.🍋 Why can’t you see the lemon writing once it dries? (a) the ink is magnetic (b) dry juice is see-through (c) the paper ate it (d) it turned into air
8. 8.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a cotton bud (b) a small bowl (c) yeast (d) white paper
9. 9.🧺 Which of these is not needed for the secret lemon message? (a) an adult with an iron (b) white paper (c) a magnet (d) a small bowl
10. 10.True or false: yeast is not needed for the secret lemon message. (a) False (b) True
11. 11.🧺 Do we need a mirror for the secret lemon message? (a) not needed (b) needed
12. 12.🔮 Predict: the adult irons for only one second. What happens? (a) writing stays faint (b) the paper floats (c) it gets darker (d) writing turns green
13. 13.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) white paper (b) a small bowl (c) lemon juice (d) a battery cell
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 same cotton bud (b) the kind of juice (c) the ironing time (d) the iron setting
15. 15.True or false: a small bowl is needed for the secret lemon message. (a) True (b) False
16. 16.True or false: writing the message is a job for an adult. (a) False (b) True
17. 17.True or false: dipping the cotton bud is a job for an adult. (a) True (b) False
18. 18.True or false: cutting the lemon is a job a child can do. (a) True (b) False
19. 19.🧺 Which of these is not needed for the secret lemon message? (a) a cotton bud (b) white paper (c) an adult with an iron (d) yeast
20. 20.🍋 Secret message: who does this step — writing the message? (a) an adult does it (b) a child can do it
21. 21.⚖️ 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
22. 22.🔍 Which is the odd one out? (a) letting the paper dry (b) writing the message (c) dipping the cotton bud (d) cutting the lemon
23. 23.True or false: a cotton bud is not needed for the secret lemon message. (a) False (b) True
24. 24.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “how dark the writing is”? (a) we measure it (b) we keep it the same (c) we change it
25. 25.🍋 Secret message: who does this step — cutting the lemon? (a) an adult does it (b) a child can do it
26. 26.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the same cotton bud is kept the same. (a) False (b) True
27. 27.True or false: letting the paper dry is a job for an adult. (a) True (b) False
28. 28.🧺 Do we need a cotton bud for the secret lemon message? (a) needed (b) not needed
29. 29.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is kept the same? (a) the ironing time (b) how dark the writing is (c) the kind of juice
30. 30.🔍 Which is the odd one out? (a) cutting the lemon (b) putting the iron away (c) reading the message (d) ironing the paper
31. 31.True or false: reading the message is a job for an adult. (a) True (b) False
32. 32.🔍 Which is the odd one out? (a) ironing the paper (b) letting the paper dry (c) cutting the lemon (d) plugging in the iron
33. 33.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a small bowl (b) white paper (c) turmeric powder (d) lemon juice
34. 34.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is what we measure? (a) how dark the writing is (b) the ironing time (c) the same cotton bud (d) the kind of juice
35. 35.🍋 Secret message: who does this step — reading the message? (a) an adult does it (b) a child can do it
36. 36.🍋 Secret message: who does this step — ironing the paper? (a) a child can do it (b) an adult does it
37. 37.🔍 Which is the odd one out? (a) plugging in the iron (b) reading the message (c) letting the paper dry (d) dipping the cotton bud
38. 38.🍋 Which of these steps is a job a child can do? (a) letting the paper dry (b) cutting the lemon (c) plugging in the iron (d) putting the iron away
39. 39.True or false: white paper is not needed for the secret lemon message. (a) True (b) False
40. 40.⚖️ 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

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