Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 752 · 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 a child can do? (a) putting the iron away (b) reading the message (c) plugging in the iron (d) ironing the paper
2. 2.🍋 Which of these steps is a job a child can do? (a) plugging in the iron (b) cutting the lemon (c) ironing the paper (d) dipping the cotton bud
3. 3.🍋 Secret message: who does this step — dipping the cotton bud? (a) an adult does it (b) a child can do it
4. 4.True or false: writing the message is a job a child can do. (a) True (b) False
5. 5.True or false: a battery cell is not needed for the secret lemon message. (a) True (b) False
6. 6.🍋 Which of these steps is a job for an adult? (a) reading the message (b) dipping the cotton bud (c) plugging in the iron (d) letting the paper dry
7. 7.🍋 Secret message: who does this step — putting the iron away? (a) a child can do it (b) an adult does it
8. 8.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the ironing time”? (a) we change it (b) we measure it (c) we keep it the same
9. 9.🍋 Why can’t you see the lemon writing once it dries? (a) dry juice is see-through (b) it turned into air (c) the ink is magnetic (d) the paper ate it
10. 10.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) skip washing (b) lick your fingers (c) rub your eyes (d) wash your hands
11. 11.⚖️ 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 iron setting (c) the same cotton bud (d) the kind of juice
12. 12.🍋 Secret message: who does this step — cutting the lemon? (a) a child can do it (b) an adult does it
13. 13.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the same paper”? (a) we change it (b) we measure it (c) we keep it the same
14. 14.True or false: an adult with an iron is not needed for the secret lemon message. (a) True (b) False
15. 15.🔮 Can the brown writing go back to being invisible? (a) yes, if shaken (b) yes, in the dark (c) no, it stays brown (d) yes, if cooled
16. 16.⚖️ 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) False (b) True
17. 17.🍋 Which of these steps is a job for an adult? (a) dipping the cotton bud (b) reading the message (c) writing the message (d) putting the iron away
18. 18.🍋 Secret message: who does this step — plugging in the iron? (a) a child can do it (b) an adult does it
19. 19.🧺 Which of these is needed for the secret lemon message? (a) turmeric powder (b) a balloon (c) lemon juice (d) a magnet
20. 20.True or false: dipping the cotton bud is a job for an adult. (a) False (b) True
21. 21.🧺 Do we need lemon juice for the secret lemon message? (a) needed (b) not needed
22. 22.🍋 Secret message: who does this step — ironing the paper? (a) an adult does it (b) a child can do it
23. 23.True or false: ironing the paper is a job a child can do. (a) True (b) False
24. 24.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) lemon juice (b) yeast (c) a small bowl (d) white paper
25. 25.🧺 Do we need a balloon for the secret lemon message? (a) not needed (b) needed
26. 26.🧺 Which of these is needed for the secret lemon message? (a) yeast (b) a balloon (c) an adult with an iron (d) a mirror
27. 27.True or false: reading the message is a job a child can do. (a) False (b) True
28. 28.🧺 Which of these is needed for the secret lemon message? (a) a mirror (b) a balloon (c) white paper (d) turmeric powder
29. 29.🛟 Why must children keep their fingers away from the iron? (a) it can burn skin (b) it is cold (c) it is sticky (d) it is magnetic
30. 30.🔮 Predict: you write with plain water instead of lemon juice. What appears after ironing? (a) dark brown words (b) almost nothing (c) blue words (d) a rainbow
31. 31.🧺 Do we need a mirror for the secret lemon message? (a) not needed (b) needed
32. 32.⚖️ 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
33. 33.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a battery cell (b) a cotton bud (c) lemon juice (d) an adult with an iron
34. 34.⚖️ 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
35. 35.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) an adult with an iron (b) a balloon (c) lemon juice (d) a cotton bud
36. 36.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is what we measure? (a) how dark the writing is (b) the iron setting (c) the ironing time (d) the kind of juice
37. 37.True or false: letting the paper dry is a job a child can do. (a) False (b) True
38. 38.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the iron setting is kept the same. (a) True (b) False
39. 39.⚖️ 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 keep it the same (c) we change it
40. 40.🧺 Which of these is not needed for the secret lemon message? (a) white paper (b) lemon juice (c) a cotton bud (d) a balloon

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