Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 929 · 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.⚖️ 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
2. 2.🧺 Do we need a cotton bud for the secret lemon message? (a) needed (b) not needed
3. 3.True or false: dipping the cotton bud is a job a child can do. (a) True (b) False
4. 4.🍋 Secret message: who does this step — ironing the paper? (a) a child can do it (b) an adult does it
5. 5.🍋 Why can’t you see the lemon writing once it dries? (a) the ink is magnetic (b) it turned into air (c) the paper ate it (d) dry juice is see-through
6. 6.True or false: dipping the cotton bud is a job for an adult. (a) False (b) True
7. 7.True or false: lemon juice is not needed for the secret lemon message. (a) True (b) False
8. 8.🛟 Why must children keep their fingers away from the iron? (a) it can burn skin (b) it is sticky (c) it is magnetic (d) it is cold
9. 9.🧺 Which of these is needed for the secret lemon message? (a) white paper (b) a balloon (c) turmeric powder (d) a mirror
10. 10.True or false: white paper is not needed for the secret lemon message. (a) False (b) True
11. 11.🍋 Which of these steps is a job a child can do? (a) cutting the lemon (b) plugging in the iron (c) letting the paper dry (d) putting the iron away
12. 12.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the same paper is what we measure. (a) False (b) True
13. 13.⚖️ 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
14. 14.True or false: a balloon is not needed for the secret lemon message. (a) False (b) True
15. 15.🧺 Which of these is not needed for the secret lemon message? (a) white paper (b) turmeric powder (c) an adult with an iron (d) lemon juice
16. 16.True or false: lemon juice is needed for the secret lemon message. (a) False (b) True
17. 17.🛟 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
18. 18.🧺 Which of these is not needed for the secret lemon message? (a) a small bowl (b) a magnet (c) an adult with an iron (d) lemon juice
19. 19.🧺 Do we need a balloon for the secret lemon message? (a) needed (b) not needed
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 keep it the same (b) we change it (c) we measure it
21. 21.🔍 Which is the odd one out? (a) plugging in the iron (b) cutting the lemon (c) writing the message (d) ironing the paper
22. 22.🧺 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) a cotton bud
23. 23.⚖️ 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) True (b) False
24. 24.🧺 Do we need white paper for the secret lemon message? (a) needed (b) not needed
25. 25.🍋 What colour does the lemon writing turn when an adult warms it? (a) white (b) green (c) brown (d) blue
26. 26.True or false: an adult with an iron is needed for the secret lemon message. (a) False (b) True
27. 27.🧺 Which of these is needed for the secret lemon message? (a) a small bowl (b) a battery cell (c) a balloon (d) turmeric powder
28. 28.🛟 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
29. 29.🔍 Which is the odd one out? (a) putting the iron away (b) dipping the cotton bud (c) plugging in the iron (d) ironing the paper
30. 30.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is what we measure? (a) the same paper (b) how dark the writing is (c) the kind of juice (d) the same cotton bud
31. 31.True or false: letting the paper dry is a job a child can do. (a) True (b) False
32. 32.🔮 Predict: you write with plain water instead of lemon juice. What appears after ironing? (a) blue words (b) dark brown words (c) a rainbow (d) almost nothing
33. 33.🍋 Which of these steps is a job a child can do? (a) ironing the paper (b) plugging in the iron (c) cutting the lemon (d) dipping the cotton bud
34. 34.🧺 Which of these is not needed for the secret lemon message? (a) an adult with an iron (b) lemon juice (c) a small bowl (d) a mirror
35. 35.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) white paper (b) lemon juice (c) an adult with an iron (d) a mirror
36. 36.🧺 Which of these is needed for the secret lemon message? (a) a balloon (b) an adult with an iron (c) a battery cell (d) turmeric powder
37. 37.True or false: plugging in the iron is a job a child can do. (a) False (b) True
38. 38.🍋 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
39. 39.True or false: putting the iron away is a job for an adult. (a) False (b) True
40. 40.🧺 Do we need an adult with an iron for the secret lemon message? (a) not needed (b) needed

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