Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 784 · 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.🍋 Why can’t you see the lemon writing once it dries? (a) dry juice is see-through (b) it turned into air (c) the paper ate it (d) the ink is magnetic
2. 2.🍋 Secret message: who does this step — cutting the lemon? (a) a child can do it (b) an adult does it
3. 3.⚖️ 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 iron setting
4. 4.🧺 Do we need a small bowl for the secret lemon message? (a) not needed (b) needed
5. 5.🍋 Which of these steps is a job a child can do? (a) plugging in the iron (b) putting the iron away (c) dipping the cotton bud (d) ironing the paper
6. 6.True or false: turmeric powder is not needed for the secret lemon message. (a) True (b) False
7. 7.True or false: a battery cell is needed for the secret lemon message. (a) False (b) True
8. 8.⚖️ 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
9. 9.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the same cotton bud”? (a) we keep it the same (b) we change it (c) we measure it
10. 10.🔮 Can the brown writing go back to being invisible? (a) yes, if cooled (b) yes, if shaken (c) no, it stays brown (d) yes, in the dark
11. 11.True or false: a mirror is not needed for the secret lemon message. (a) True (b) False
12. 12.🧺 Do we need white paper for the secret lemon message? (a) needed (b) not needed
13. 13.🧺 Which of these is needed for the secret lemon message? (a) a balloon (b) a battery cell (c) turmeric powder (d) a cotton bud
14. 14.🧺 Which of these is needed for the secret lemon message? (a) a magnet (b) a mirror (c) yeast (d) a small bowl
15. 15.🧺 Which of these is needed for the secret lemon message? (a) a magnet (b) yeast (c) a balloon (d) an adult with an iron
16. 16.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the same paper is kept the same. (a) True (b) False
17. 17.True or false: a battery cell is not needed for the secret lemon message. (a) False (b) True
18. 18.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a magnet (b) white paper (c) a small bowl (d) a cotton bud
19. 19.🔍 Which is the odd one out? (a) letting the paper dry (b) putting the iron away (c) writing the message (d) reading the message
20. 20.🧺 Do we need a balloon for the secret lemon message? (a) needed (b) not needed
21. 21.🔮 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
22. 22.True or false: lemon juice is not needed for the secret lemon message. (a) False (b) True
23. 23.⚖️ 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
24. 24.⚖️ 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) False (b) True
25. 25.🛟 Why must children keep their fingers away from the iron? (a) it is cold (b) it is magnetic (c) it is sticky (d) it can burn skin
26. 26.🍋 Secret message: who does this step — writing the message? (a) a child can do it (b) an adult does it
27. 27.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) yeast (b) an adult with an iron (c) a cotton bud (d) white paper
28. 28.True or false: yeast is needed for the secret lemon message. (a) True (b) False
29. 29.🛟 Who should use the hot iron in the secret message experiment? (a) the youngest child (b) whoever is fastest (c) only an adult (d) any child
30. 30.🔮 Predict: the adult irons for only one second. What happens? (a) writing turns green (b) writing stays faint (c) it gets darker (d) the paper floats
31. 31.🍋 Which of these steps is a job a child can do? (a) plugging in the iron (b) putting the iron away (c) reading the message (d) ironing the paper
32. 32.⚖️ 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
33. 33.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) lemon juice (b) a small bowl (c) a mirror (d) white paper
34. 34.True or false: white paper is not needed for the secret lemon message. (a) True (b) False
35. 35.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) turmeric powder (b) a cotton bud (c) an adult with an iron (d) lemon juice
36. 36.🔍 Which is the odd one out? (a) putting the iron away (b) cutting the lemon (c) plugging in the iron (d) letting the paper dry
37. 37.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) white paper (b) an adult with an iron (c) a small bowl (d) a balloon
38. 38.True or false: a magnet is needed for the secret lemon message. (a) True (b) False
39. 39.True or false: writing the message is a job for an adult. (a) True (b) False
40. 40.🧺 Which of these is not needed for the secret lemon message? (a) lemon juice (b) an adult with an iron (c) a cotton bud (d) a magnet

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