Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 530 · 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 magnet (b) an adult with an iron (c) a cotton bud (d) white paper
2. 2.🍋 Secret message: who does this step — reading the message? (a) a child can do it (b) an adult does it
3. 3.🧺 Which of these is needed for the secret lemon message? (a) white paper (b) a balloon (c) a magnet (d) a battery cell
4. 4.🧺 Which of these is not needed for the secret lemon message? (a) lemon juice (b) yeast (c) an adult with an iron (d) white paper
5. 5.🍋 Why can’t you see the lemon writing once it dries? (a) the ink is magnetic (b) the paper ate it (c) dry juice is see-through (d) it turned into air
6. 6.🧺 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) turmeric powder
7. 7.🧺 Which of these is needed for the secret lemon message? (a) yeast (b) a balloon (c) lemon juice (d) a magnet
8. 8.🧺 Which of these is needed for the secret lemon message? (a) a magnet (b) turmeric powder (c) a cotton bud (d) yeast
9. 9.🔮 Predict: the adult irons for only one second. What happens? (a) writing turns green (b) the paper floats (c) it gets darker (d) writing stays faint
10. 10.🍋 What colour does the lemon writing turn when an adult warms it? (a) blue (b) brown (c) white (d) green
11. 11.🧺 Do we need a small bowl for the secret lemon message? (a) needed (b) not needed
12. 12.🧺 Which of these is not needed for the secret lemon message? (a) a cotton bud (b) a small bowl (c) a magnet (d) white paper
13. 13.True or false: turmeric powder is needed for the secret lemon message. (a) False (b) True
14. 14.⚖️ 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) False (b) True
15. 15.⚖️ 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
16. 16.True or false: a small bowl is needed for the secret lemon message. (a) False (b) True
17. 17.⚖️ 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
18. 18.🔍 Which is the odd one out? (a) letting the paper dry (b) writing the message (c) reading the message (d) cutting the lemon
19. 19.⚖️ 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 kind of juice (c) the ironing time (d) the same paper
20. 20.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the kind of juice is what we measure. (a) False (b) True
21. 21.True or false: a small bowl is not needed for the secret lemon message. (a) True (b) False
22. 22.🧺 Do we need a mirror for the secret lemon message? (a) needed (b) not needed
23. 23.🛟 Who should use the hot iron in the secret message experiment? (a) only an adult (b) any child (c) the youngest child (d) whoever is fastest
24. 24.🧺 Do we need a cotton bud for the secret lemon message? (a) needed (b) not needed
25. 25.True or false: dipping the cotton bud is a job for an adult. (a) True (b) False
26. 26.🧺 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) white paper (d) a balloon
27. 27.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) lick your fingers (b) skip washing (c) rub your eyes (d) wash your hands
28. 28.⚖️ 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 change it (c) we keep it the same
29. 29.🔍 Which is the odd one out? (a) reading the message (b) writing the message (c) dipping the cotton bud (d) plugging in the iron
30. 30.🍋 Why does the lemon writing turn brown with heat? (a) paper turns lemony (b) the juice scorches first (c) heat adds colour (d) the iron is brown
31. 31.⚖️ 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 measure it (c) we keep it the same
32. 32.🔮 Predict: you write with plain water instead of lemon juice. What appears after ironing? (a) a rainbow (b) dark brown words (c) blue words (d) almost nothing
33. 33.True or false: cutting the lemon is a job for an adult. (a) False (b) True
34. 34.⚖️ 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 kind of juice (c) the same cotton bud
35. 35.🧺 Do we need lemon juice for the secret lemon message? (a) needed (b) not needed
36. 36.🧺 Which of these is needed for the secret lemon message? (a) a mirror (b) an adult with an iron (c) yeast (d) turmeric powder
37. 37.⚖️ 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) False (b) True
38. 38.⚖️ 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 kind of juice (c) the ironing time
39. 39.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) white paper (b) lemon juice (c) a mirror (d) a cotton bud
40. 40.True or false: white paper is not needed for the secret lemon message. (a) True (b) False

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