Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 803 · 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.🧺 Do we need a magnet for the secret lemon message? (a) needed (b) not needed
2. 2.True or false: cutting the lemon is a job for an adult. (a) False (b) True
3. 3.🧺 Do we need a balloon for the secret lemon message? (a) not needed (b) needed
4. 4.🧺 Which of these is needed for the secret lemon message? (a) a mirror (b) a balloon (c) an adult with an iron (d) a magnet
5. 5.🔍 Which is the odd one out? (a) dipping the cotton bud (b) reading the message (c) letting the paper dry (d) ironing the paper
6. 6.⚖️ 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
7. 7.🍋 Which of these steps is a job for an adult? (a) letting the paper dry (b) dipping the cotton bud (c) reading the message (d) cutting the lemon
8. 8.🍋 Which of these steps is a job a child can do? (a) cutting the lemon (b) putting the iron away (c) plugging in the iron (d) letting the paper dry
9. 9.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) lemon juice (b) a cotton bud (c) white paper (d) turmeric powder
10. 10.🍋 Why does the lemon writing turn brown with heat? (a) heat adds colour (b) paper turns lemony (c) the iron is brown (d) the juice scorches first
11. 11.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) wash your hands (b) skip washing (c) lick your fingers (d) rub your eyes
12. 12.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is kept the same? (a) the iron setting (b) the kind of juice (c) how dark the writing is
13. 13.🍋 Which of these steps is a job for an adult? (a) dipping the cotton bud (b) reading the message (c) putting the iron away (d) writing the message
14. 14.⚖️ 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 keep it the same (c) we change it
15. 15.⚖️ 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 keep it the same (c) we change it
16. 16.True or false: turmeric powder is needed for the secret lemon message. (a) False (b) True
17. 17.🔮 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
18. 18.🔮 Predict: you write with plain water instead of lemon juice. What appears after ironing? (a) blue words (b) dark brown words (c) almost nothing (d) a rainbow
19. 19.True or false: a mirror is not needed for the secret lemon message. (a) False (b) True
20. 20.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) white paper (b) a cotton bud (c) lemon juice (d) yeast
21. 21.🍋 Which of these steps is a job a child can do? (a) writing the message (b) putting the iron away (c) plugging in the iron (d) cutting the lemon
22. 22.⚖️ 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 same paper (c) the kind of juice (d) the same cotton bud
23. 23.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the iron setting”? (a) we keep it the same (b) we change it (c) we measure it
24. 24.🔍 Which is the odd one out? (a) cutting the lemon (b) plugging in the iron (c) reading the message (d) putting the iron away
25. 25.🔮 Can the brown writing go back to being invisible? (a) no, it stays brown (b) yes, if cooled (c) yes, if shaken (d) yes, in the dark
26. 26.🧺 Do we need turmeric powder for the secret lemon message? (a) not needed (b) needed
27. 27.🍋 Secret message: who does this step — cutting the lemon? (a) a child can do it (b) an adult does it
28. 28.🍋 Secret message: who does this step — plugging in the iron? (a) an adult does it (b) a child can do it
29. 29.True or false: putting the iron away is a job a child can do. (a) True (b) False
30. 30.🍋 Secret message: who does this step — putting the iron away? (a) an adult does it (b) a child can do it
31. 31.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a small bowl (b) a battery cell (c) an adult with an iron (d) white paper
32. 32.🧺 Which of these is not needed for the secret lemon message? (a) a cotton bud (b) a mirror (c) lemon juice (d) white paper
33. 33.🧺 Which of these is not needed for the secret lemon message? (a) a small bowl (b) lemon juice (c) a cotton bud (d) yeast
34. 34.True or false: a small bowl is not needed for the secret lemon message. (a) True (b) False
35. 35.🧺 Which of these is needed for the secret lemon message? (a) yeast (b) lemon juice (c) a magnet (d) a mirror
36. 36.🍋 Why can’t you see the lemon writing once it dries? (a) the paper ate it (b) dry juice is see-through (c) it turned into air (d) the ink is magnetic
37. 37.True or false: an adult with an iron is needed for the secret lemon message. (a) False (b) True
38. 38.⚖️ 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
39. 39.🧺 Do we need a cotton bud for the secret lemon message? (a) not needed (b) needed
40. 40.🔍 Which is the odd one out? (a) writing the message (b) putting the iron away (c) ironing the paper (d) cutting the lemon

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