Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 962 · 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? What do we do with “the same cotton bud”? (a) we keep it the same (b) we change it (c) we measure it
2. 2.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a small bowl (b) a balloon (c) an adult with an iron (d) lemon juice
3. 3.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is kept the same? (a) the iron setting (b) how dark the writing is (c) the kind of juice
4. 4.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) white paper (b) a small bowl (c) an adult with an iron (d) yeast
5. 5.🧺 Do we need lemon juice for the secret lemon message? (a) needed (b) not needed
6. 6.⚖️ 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 ironing time (c) the iron setting (d) the same cotton bud
7. 7.🍋 Which of these steps is a job for an adult? (a) writing the message (b) dipping the cotton bud (c) cutting the lemon (d) reading the message
8. 8.🧺 Do we need a balloon for the secret lemon message? (a) not needed (b) needed
9. 9.🔮 Predict: the adult irons for only one second. What happens? (a) writing stays faint (b) writing turns green (c) the paper floats (d) it gets darker
10. 10.🛟 Who should use the hot iron in the secret message experiment? (a) whoever is fastest (b) any child (c) only an adult (d) the youngest child
11. 11.True or false: white paper is not needed for the secret lemon message. (a) True (b) False
12. 12.🧺 Do we need a cotton bud for the secret lemon message? (a) not needed (b) needed
13. 13.🍋 Secret message: who does this step — writing the message? (a) a child can do it (b) an adult does it
14. 14.True or false: ironing the paper is a job a child can do. (a) False (b) True
15. 15.True or false: writing the message is a job for an adult. (a) True (b) False
16. 16.🔮 Predict: you write with plain water instead of lemon juice. What appears after ironing? (a) blue words (b) dark brown words (c) almost nothing (d) a rainbow
17. 17.🍋 Which of these steps is a job for an adult? (a) ironing the paper (b) dipping the cotton bud (c) reading the message (d) writing the message
18. 18.True or false: a cotton bud is needed for the secret lemon message. (a) True (b) False
19. 19.🧺 Do we need turmeric powder for the secret lemon message? (a) needed (b) not needed
20. 20.🧺 Which of these is not needed for the secret lemon message? (a) lemon juice (b) white paper (c) a cotton bud (d) yeast
21. 21.🔍 Which is the odd one out? (a) dipping the cotton bud (b) ironing the paper (c) writing the message (d) letting the paper dry
22. 22.True or false: a small bowl is needed for the secret lemon message. (a) False (b) True
23. 23.⚖️ 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 keep it the same (c) we measure it
24. 24.🧺 Do we need a mirror for the secret lemon message? (a) needed (b) not needed
25. 25.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the kind of juice is what we measure. (a) True (b) False
26. 26.True or false: plugging in the iron is a job a child can do. (a) False (b) True
27. 27.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a small bowl (b) turmeric powder (c) white paper (d) lemon juice
28. 28.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the kind of juice is the one thing we change. (a) True (b) False
29. 29.🍋 Which of these steps is a job for an adult? (a) letting the paper dry (b) dipping the cotton bud (c) putting the iron away (d) reading the message
30. 30.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) skip washing (b) rub your eyes (c) wash your hands (d) lick your fingers
31. 31.🧺 Do we need a small bowl for the secret lemon message? (a) needed (b) not needed
32. 32.🍋 Secret message: who does this step — plugging in the iron? (a) a child can do it (b) an adult does it
33. 33.🍋 Secret message: who does this step — ironing the paper? (a) an adult does it (b) a child can do it
34. 34.🧺 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 mirror
35. 35.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the iron setting”? (a) we keep it the same (b) we change it (c) we measure it
36. 36.🛟 Why must children keep their fingers away from the iron? (a) it is cold (b) it is sticky (c) it is magnetic (d) it can burn skin
37. 37.True or false: a cotton bud is not needed for the secret lemon message. (a) True (b) False
38. 38.🍋 Which of these steps is a job a child can do? (a) cutting the lemon (b) plugging in the iron (c) writing the message (d) ironing the paper
39. 39.🧺 Which of these is not needed for the secret lemon message? (a) white paper (b) lemon juice (c) a mirror (d) an adult with an iron
40. 40.True or false: an adult with an iron is not needed for the secret lemon message. (a) False (b) True

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