Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 176 · 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) lemon juice (c) white paper (d) a magnet
2. 2.True or false: yeast is needed for the secret lemon message. (a) True (b) False
3. 3.⚖️ 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 cotton bud (c) the same paper (d) how dark the writing is
4. 4.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the ironing time is what we measure. (a) False (b) True
5. 5.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is kept the same? (a) how dark the writing is (b) the same paper (c) the kind of juice
6. 6.🧺 Which of these is not needed for the secret lemon message? (a) white paper (b) lemon juice (c) an adult with an iron (d) turmeric powder
7. 7.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “how dark the writing is”? (a) we change it (b) we keep it the same (c) we measure it
8. 8.True or false: an adult with an iron is needed for the secret lemon message. (a) True (b) False
9. 9.🧺 Which of these is needed for the secret lemon message? (a) a cotton bud (b) a balloon (c) a battery cell (d) a mirror
10. 10.True or false: dipping the cotton bud is a job a child can do. (a) True (b) False
11. 11.🧺 Do we need lemon juice for the secret lemon message? (a) not needed (b) needed
12. 12.⚖️ 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
13. 13.🍋 What colour does the lemon writing turn when an adult warms it? (a) blue (b) white (c) brown (d) green
14. 14.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) an adult with an iron (b) yeast (c) a small bowl (d) a cotton bud
15. 15.🧺 Which of these is needed for the secret lemon message? (a) a mirror (b) a balloon (c) turmeric powder (d) lemon juice
16. 16.🍋 Why does the lemon writing turn brown with heat? (a) heat adds colour (b) the iron is brown (c) paper turns lemony (d) the juice scorches first
17. 17.🧺 Which of these is not needed for the secret lemon message? (a) lemon juice (b) an adult with an iron (c) a mirror (d) a small bowl
18. 18.True or false: reading the message is a job a child can do. (a) True (b) False
19. 19.🔮 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
20. 20.🧺 Do we need a magnet for the secret lemon message? (a) needed (b) not needed
21. 21.🍋 Which of these steps is a job a child can do? (a) reading the message (b) putting the iron away (c) ironing the paper (d) plugging in the iron
22. 22.True or false: writing the message is a job a child can do. (a) False (b) True
23. 23.🧺 Do we need white paper for the secret lemon message? (a) not needed (b) needed
24. 24.🔮 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
25. 25.🔍 Which is the odd one out? (a) putting the iron away (b) ironing the paper (c) reading the message (d) plugging in the iron
26. 26.🍋 Secret message: who does this step — dipping the cotton bud? (a) a child can do it (b) an adult does it
27. 27.⚖️ 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 change it (c) we keep it the same
28. 28.📘 The browning of lemon juice with heat is a ___ change. (a) musical (b) physical (c) chemical (d) magnetic
29. 29.True or false: a small bowl is needed for the secret lemon message. (a) False (b) True
30. 30.⚖️ 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 kind of juice (c) the ironing time (d) the same cotton bud
31. 31.🔍 Which is the odd one out? (a) reading the message (b) dipping the cotton bud (c) putting the iron away (d) letting the paper dry
32. 32.🍋 Secret message: who does this step — ironing the paper? (a) a child can do it (b) an adult does it
33. 33.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) skip washing (b) lick your fingers (c) wash your hands (d) rub your eyes
34. 34.True or false: a battery cell is not needed for the secret lemon message. (a) False (b) True
35. 35.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) turmeric powder (b) white paper (c) lemon juice (d) a cotton bud
36. 36.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a balloon (b) an adult with an iron (c) a cotton bud (d) lemon juice
37. 37.True or false: lemon juice is not needed for the secret lemon message. (a) True (b) False
38. 38.⚖️ 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
39. 39.🧺 Which of these is not needed for the secret lemon message? (a) white paper (b) a magnet (c) lemon juice (d) a cotton bud
40. 40.⚖️ 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

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