Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 847 · 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 white paper for the secret lemon message? (a) not needed (b) needed
2. 2.True or false: white paper is not needed for the secret lemon message. (a) False (b) True
3. 3.🍋 Which of these steps is a job for an adult? (a) letting the paper dry (b) dipping the cotton bud (c) ironing the paper (d) reading the message
4. 4.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is the one thing we change? (a) the ironing time (b) the kind of juice (c) the iron setting (d) how dark the writing is
5. 5.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is what we measure? (a) the same cotton bud (b) how dark the writing is (c) the kind of juice (d) the ironing time
6. 6.🍋 Which of these steps is a job for an adult? (a) letting the paper dry (b) reading the message (c) cutting the lemon (d) dipping the cotton bud
7. 7.🧺 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) white paper (d) a cotton bud
8. 8.⚖️ 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 change it (c) we keep it the same
9. 9.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a cotton bud (b) lemon juice (c) turmeric powder (d) white paper
10. 10.🧺 Do we need a battery cell for the secret lemon message? (a) needed (b) not needed
11. 11.🍋 Which of these steps is a job a child can do? (a) putting the iron away (b) cutting the lemon (c) reading the message (d) ironing the paper
12. 12.🍋 Secret message: who does this step — plugging in the iron? (a) a child can do it (b) an adult does it
13. 13.🍋 Secret message: who does this step — cutting the lemon? (a) an adult does it (b) a child can do it
14. 14.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the ironing time is what we measure. (a) True (b) False
15. 15.🔮 Predict: you write with plain water instead of lemon juice. What appears after ironing? (a) dark brown words (b) a rainbow (c) almost nothing (d) blue words
16. 16.🍋 Why can’t you see the lemon writing once it dries? (a) it turned into air (b) dry juice is see-through (c) the paper ate it (d) the ink is magnetic
17. 17.🔮 Can the brown writing go back to being invisible? (a) yes, if shaken (b) yes, in the dark (c) yes, if cooled (d) no, it stays brown
18. 18.True or false: writing the message is a job a child can do. (a) False (b) True
19. 19.⚖️ 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
20. 20.⚖️ 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
21. 21.🔍 Which is the odd one out? (a) putting the iron away (b) plugging in the iron (c) ironing the paper (d) letting the paper dry
22. 22.🧺 Do we need turmeric powder for the secret lemon message? (a) needed (b) not needed
23. 23.🧺 Which of these is not needed for the secret lemon message? (a) a small bowl (b) a balloon (c) a cotton bud (d) white paper
24. 24.🧺 Which of these is needed for the secret lemon message? (a) lemon juice (b) a mirror (c) a battery cell (d) a magnet
25. 25.🍋 Secret message: who does this step — dipping the cotton bud? (a) an adult does it (b) a child can do it
26. 26.True or false: turmeric powder is needed for the secret lemon message. (a) False (b) True
27. 27.📘 The browning of lemon juice with heat is a ___ change. (a) physical (b) musical (c) chemical (d) magnetic
28. 28.True or false: reading the message is a job a child can do. (a) False (b) True
29. 29.🧺 Which of these is not needed for the secret lemon message? (a) white paper (b) a cotton bud (c) lemon juice (d) a mirror
30. 30.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a cotton bud (b) a battery cell (c) an adult with an iron (d) white paper
31. 31.🍋 Secret message: who does this step — reading the message? (a) a child can do it (b) an adult does it
32. 32.🛟 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
33. 33.🍋 Secret message: who does this step — writing the message? (a) a child can do it (b) an adult does it
34. 34.🔍 Which is the odd one out? (a) letting the paper dry (b) writing the message (c) dipping the cotton bud (d) ironing the paper
35. 35.🍋 Which of these steps is a job a child can do? (a) cutting the lemon (b) plugging in the iron (c) putting the iron away (d) writing the message
36. 36.⚖️ 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
37. 37.🍋 Secret message: who does this step — letting the paper dry? (a) an adult does it (b) a child can do it
38. 38.🍋 What colour does the lemon writing turn when an adult warms it? (a) white (b) green (c) brown (d) blue
39. 39.🧺 Do we need a cotton bud for the secret lemon message? (a) needed (b) not needed
40. 40.⚖️ 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

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