Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 426 · 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.🍋 Which of these steps is a job for an adult? (a) letting the paper dry (b) writing the message (c) plugging in the iron (d) reading the message
2. 2.🍋 Which of these steps is a job for an adult? (a) writing the message (b) cutting the lemon (c) dipping the cotton bud (d) reading the message
3. 3.🛟 Who should use the hot iron in the secret message experiment? (a) the youngest child (b) whoever is fastest (c) any child (d) only an adult
4. 4.🔍 Which is the odd one out? (a) reading the message (b) plugging in the iron (c) letting the paper dry (d) writing the message
5. 5.🧺 Do we need lemon juice for the secret lemon message? (a) not needed (b) needed
6. 6.True or false: a battery cell is not needed for the secret lemon message. (a) False (b) True
7. 7.🍋 Which of these steps is a job for an adult? (a) writing the message (b) reading the message (c) putting the iron away (d) dipping the cotton bud
8. 8.⚖️ 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
9. 9.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the same cotton bud is the one thing we change. (a) True (b) False
10. 10.⚖️ 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 measure it (c) we keep it the same
11. 11.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) lemon juice (b) a small bowl (c) turmeric powder (d) an adult with an iron
12. 12.🔍 Which is the odd one out? (a) cutting the lemon (b) putting the iron away (c) writing the message (d) ironing the paper
13. 13.🍋 Which of these steps is a job for an adult? (a) dipping the cotton bud (b) writing the message (c) reading the message (d) ironing the paper
14. 14.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a small bowl (b) lemon juice (c) a magnet (d) an adult with an iron
15. 15.🔍 Which is the odd one out? (a) ironing the paper (b) writing the message (c) reading the message (d) letting the paper dry
16. 16.🛟 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
17. 17.🧺 Which of these is needed for the secret lemon message? (a) turmeric powder (b) yeast (c) a magnet (d) an adult with an iron
18. 18.🔮 Can the brown writing go back to being invisible? (a) yes, if shaken (b) no, it stays brown (c) yes, if cooled (d) yes, in the dark
19. 19.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is the one thing we change? (a) the same cotton bud (b) the same paper (c) the iron setting (d) the kind of juice
20. 20.True or false: a magnet is needed for the secret lemon message. (a) True (b) False
21. 21.True or false: a mirror is not needed for the secret lemon message. (a) False (b) True
22. 22.🍋 Secret message: who does this step — plugging in the iron? (a) an adult does it (b) a child can do it
23. 23.🛟 Why must children keep their fingers away from the iron? (a) it is sticky (b) it is magnetic (c) it can burn skin (d) it is cold
24. 24.🧺 Do we need white paper for the secret lemon message? (a) needed (b) not needed
25. 25.🧺 Do we need a balloon for the secret lemon message? (a) needed (b) not needed
26. 26.📘 The browning of lemon juice with heat is a ___ change. (a) musical (b) chemical (c) physical (d) magnetic
27. 27.🔮 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
28. 28.⚖️ 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 change it (c) we measure it
29. 29.🧺 Which of these is needed for the secret lemon message? (a) a balloon (b) yeast (c) a magnet (d) a cotton bud
30. 30.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a small bowl (b) a battery cell (c) lemon juice (d) white paper
31. 31.🧺 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 balloon (d) a small bowl
32. 32.True or false: dipping the cotton bud is a job for an adult. (a) True (b) False
33. 33.🍋 Secret message: who does this step — ironing the paper? (a) an adult does it (b) a child can do it
34. 34.🧺 Which of these is not needed for the secret lemon message? (a) white paper (b) a cotton bud (c) a small bowl (d) a battery cell
35. 35.True or false: an adult with an iron is needed for the secret lemon message. (a) False (b) True
36. 36.True or false: a magnet is not needed for the secret lemon message. (a) False (b) True
37. 37.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the same cotton bud is kept the same. (a) False (b) True
38. 38.True or false: ironing the paper is a job a child can do. (a) True (b) False
39. 39.🧺 Which of these is not needed for the secret lemon message? (a) a balloon (b) white paper (c) a cotton bud (d) lemon juice
40. 40.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) white paper (b) a cotton bud (c) a mirror (d) lemon juice

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