Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 507 · 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) an adult with an iron (c) a small bowl (d) a balloon
2. 2.🍋 Secret message: who does this step — dipping the cotton bud? (a) a child can do it (b) an adult does it
3. 3.🔍 Which is the odd one out? (a) letting the paper dry (b) reading the message (c) cutting the lemon (d) dipping the cotton bud
4. 4.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) an adult with an iron (b) a cotton bud (c) a small bowl (d) a mirror
5. 5.True or false: a small bowl is needed for the secret lemon message. (a) True (b) False
6. 6.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the same cotton bud is what we measure. (a) False (b) True
7. 7.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is the one thing we change? (a) how dark the writing is (b) the ironing time (c) the kind of juice (d) the iron setting
8. 8.🧺 Do we need a magnet for the secret lemon message? (a) needed (b) not needed
9. 9.🔍 Which is the odd one out? (a) reading the message (b) dipping the cotton bud (c) writing the message (d) plugging in the iron
10. 10.🧺 Which of these is not needed for the secret lemon message? (a) a small bowl (b) white paper (c) an adult with an iron (d) turmeric powder
11. 11.True or false: plugging in the iron is a job a child can do. (a) True (b) False
12. 12.🍋 Secret message: who does this step — cutting the lemon? (a) a child can do it (b) an adult does it
13. 13.🍋 Which of these steps is a job for an adult? (a) dipping the cotton bud (b) writing the message (c) plugging in the iron (d) reading the message
14. 14.🧺 Which of these is needed for the secret lemon message? (a) a cotton bud (b) a mirror (c) yeast (d) a balloon
15. 15.🛟 Who should use the hot iron in the secret message experiment? (a) the youngest child (b) whoever is fastest (c) any child (d) only an adult
16. 16.🛟 Why must children keep their fingers away from the iron? (a) it is cold (b) it can burn skin (c) it is magnetic (d) it is sticky
17. 17.🍋 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
18. 18.True or false: cutting the lemon is a job for an adult. (a) False (b) True
19. 19.🔍 Which is the odd one out? (a) plugging in the iron (b) cutting the lemon (c) ironing the paper (d) writing the message
20. 20.⚖️ 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
21. 21.📘 The browning of lemon juice with heat is a ___ change. (a) physical (b) magnetic (c) musical (d) chemical
22. 22.⚖️ 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
23. 23.🔮 Predict: you write with plain water instead of lemon juice. What appears after ironing? (a) dark brown words (b) a rainbow (c) blue words (d) almost nothing
24. 24.⚖️ 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
25. 25.🛟 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
26. 26.🔮 Predict: the adult irons for only one second. What happens? (a) the paper floats (b) writing stays faint (c) it gets darker (d) writing turns green
27. 27.True or false: reading the message is a job a child can do. (a) False (b) True
28. 28.True or false: lemon juice is not needed for the secret lemon message. (a) True (b) False
29. 29.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a cotton bud (b) white paper (c) turmeric powder (d) lemon juice
30. 30.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is what we measure? (a) the kind of juice (b) the same paper (c) the ironing time (d) how dark the writing is
31. 31.True or false: ironing the paper is a job a child can do. (a) True (b) False
32. 32.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the kind of juice”? (a) we measure it (b) we keep it the same (c) we change it
33. 33.🍋 Secret message: who does this step — plugging in the iron? (a) an adult does it (b) a child can do it
34. 34.🍋 Which of these steps is a job a child can do? (a) dipping the cotton bud (b) ironing the paper (c) plugging in the iron (d) cutting the lemon
35. 35.🧺 Do we need a battery cell for the secret lemon message? (a) not needed (b) needed
36. 36.🔍 Which is the odd one out? (a) putting the iron away (b) cutting the lemon (c) ironing the paper (d) dipping the cotton bud
37. 37.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) lemon juice (b) a magnet (c) a small bowl (d) a cotton bud
38. 38.🍋 Secret message: who does this step — writing the message? (a) a child can do it (b) an adult does it
39. 39.🧺 Which of these is needed for the secret lemon message? (a) yeast (b) white paper (c) turmeric powder (d) a mirror
40. 40.⚖️ 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

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