Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 859 · 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 is needed for the secret lemon message? (a) a mirror (b) yeast (c) a battery cell (d) an adult with an iron
2. 2.True or false: turmeric powder is not needed for the secret lemon message. (a) False (b) True
3. 3.🔍 Which is the odd one out? (a) writing the message (b) reading the message (c) ironing the paper (d) letting the paper dry
4. 4.🔍 Which is the odd one out? (a) plugging in the iron (b) cutting the lemon (c) writing the message (d) ironing the paper
5. 5.🧺 Which of these is not needed for the secret lemon message? (a) a small bowl (b) a cotton bud (c) yeast (d) lemon juice
6. 6.⚖️ 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
7. 7.🧺 Do we need a battery cell for the secret lemon message? (a) needed (b) not needed
8. 8.🧺 Which of these is not needed for the secret lemon message? (a) a cotton bud (b) a mirror (c) white paper (d) an adult with an iron
9. 9.🔍 Which is the odd one out? (a) cutting the lemon (b) reading the message (c) ironing the paper (d) plugging in the iron
10. 10.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the same paper is kept the same. (a) False (b) True
11. 11.🍋 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
12. 12.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a magnet (b) a cotton bud (c) an adult with an iron (d) lemon juice
13. 13.True or false: writing the message is a job for an adult. (a) False (b) True
14. 14.🍋 Which of these steps is a job for an adult? (a) writing the message (b) dipping the cotton bud (c) putting the iron away (d) letting the paper dry
15. 15.🍋 Which of these steps is a job a child can do? (a) ironing the paper (b) putting the iron away (c) dipping the cotton bud (d) cutting the lemon
16. 16.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the ironing time is the one thing we change. (a) True (b) False
17. 17.🛟 Who should use the hot iron in the secret message experiment? (a) only an adult (b) whoever is fastest (c) the youngest child (d) any child
18. 18.🍋 Secret message: who does this step — letting the paper dry? (a) a child can do it (b) an adult does it
19. 19.True or false: reading the message is a job a child can do. (a) True (b) False
20. 20.🍋 Secret message: who does this step — writing the message? (a) an adult does it (b) a child can do it
21. 21.🛟 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
22. 22.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) lemon juice (b) a cotton bud (c) an adult with an iron (d) a battery cell
23. 23.True or false: a mirror is not needed for the secret lemon message. (a) True (b) False
24. 24.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the iron setting”? (a) we measure it (b) we keep it the same (c) we change it
25. 25.⚖️ 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
26. 26.🍋 What colour does the lemon writing turn when an adult warms it? (a) green (b) brown (c) blue (d) white
27. 27.🧺 Which of these is not needed for the secret lemon message? (a) lemon juice (b) a cotton bud (c) turmeric powder (d) a small bowl
28. 28.🧺 Which of these is needed for the secret lemon message? (a) a small bowl (b) turmeric powder (c) yeast (d) a battery cell
29. 29.⚖️ 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
30. 30.🧺 Which of these is needed for the secret lemon message? (a) yeast (b) lemon juice (c) turmeric powder (d) a balloon
31. 31.🍋 Which of these steps is a job a child can do? (a) reading the message (b) cutting the lemon (c) ironing the paper (d) plugging in the iron
32. 32.📘 The browning of lemon juice with heat is a ___ change. (a) physical (b) magnetic (c) musical (d) chemical
33. 33.🔮 Predict: you write with plain water instead of lemon juice. What appears after ironing? (a) a rainbow (b) almost nothing (c) dark brown words (d) blue words
34. 34.🧺 Which of these is needed for the secret lemon message? (a) a balloon (b) a mirror (c) yeast (d) white paper
35. 35.🔍 Which is the odd one out? (a) putting the iron away (b) letting the paper dry (c) reading the message (d) writing the message
36. 36.🍋 Secret message: who does this step — ironing the paper? (a) an adult does it (b) a child can do it
37. 37.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) lemon juice (b) a small bowl (c) white paper (d) yeast
38. 38.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the ironing time is kept the same. (a) True (b) False
39. 39.🍋 Why can’t you see the lemon writing once it dries? (a) the paper ate it (b) it turned into air (c) the ink is magnetic (d) dry juice is see-through
40. 40.🧺 Do we need a small bowl for the secret lemon message? (a) needed (b) not needed

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