Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 656 · 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.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a cotton bud (b) a battery cell (c) white paper (d) an adult with an iron
2. 2.🍋 Secret message: who does this step — letting the paper dry? (a) an adult does it (b) a child can do it
3. 3.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) turmeric powder (b) an adult with an iron (c) a cotton bud (d) lemon juice
4. 4.🧺 Do we need a small bowl for the secret lemon message? (a) not needed (b) needed
5. 5.🍋 Which of these steps is a job a child can do? (a) putting the iron away (b) plugging in the iron (c) ironing the paper (d) letting the paper dry
6. 6.True or false: putting the iron away is a job for an adult. (a) False (b) True
7. 7.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is the one thing we change? (a) the same paper (b) the iron setting (c) the same cotton bud (d) the kind of juice
8. 8.🍋 Secret message: who does this step — reading the message? (a) a child can do it (b) an adult does it
9. 9.⚖️ 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 change it (c) we keep it the same
10. 10.🔮 Predict: you write with plain water instead of lemon juice. What appears after ironing? (a) blue words (b) almost nothing (c) dark brown words (d) a rainbow
11. 11.🔍 Which is the odd one out? (a) plugging in the iron (b) ironing the paper (c) dipping the cotton bud (d) putting the iron away
12. 12.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a cotton bud (b) a mirror (c) lemon juice (d) a small bowl
13. 13.🍋 Which of these steps is a job for an adult? (a) dipping the cotton bud (b) letting the paper dry (c) writing the message (d) ironing the paper
14. 14.🧺 Do we need a magnet for the secret lemon message? (a) needed (b) not needed
15. 15.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the kind of juice is kept the same. (a) True (b) False
16. 16.🔮 Predict: the adult irons for only one second. What happens? (a) writing turns green (b) the paper floats (c) writing stays faint (d) it gets darker
17. 17.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a cotton bud (b) yeast (c) an adult with an iron (d) a small bowl
18. 18.🍋 Which of these steps is a job a child can do? (a) cutting the lemon (b) plugging in the iron (c) dipping the cotton bud (d) ironing the paper
19. 19.🧺 Do we need white paper for the secret lemon message? (a) not needed (b) needed
20. 20.True or false: lemon juice is needed for the secret lemon message. (a) True (b) False
21. 21.🧺 Which of these is needed for the secret lemon message? (a) a mirror (b) a magnet (c) an adult with an iron (d) yeast
22. 22.🍋 Secret message: who does this step — dipping the cotton bud? (a) an adult does it (b) a child can do it
23. 23.🧺 Do we need an adult with an iron for the secret lemon message? (a) needed (b) not needed
24. 24.🧺 Which of these is needed for the secret lemon message? (a) a magnet (b) a balloon (c) a small bowl (d) a mirror
25. 25.🛟 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
26. 26.📘 The browning of lemon juice with heat is a ___ change. (a) physical (b) musical (c) chemical (d) magnetic
27. 27.🍋 Which of these steps is a job for an adult? (a) plugging in the iron (b) dipping the cotton bud (c) writing the message (d) reading the message
28. 28.True or false: plugging in the iron is a job for an adult. (a) True (b) False
29. 29.🛟 Why must children keep their fingers away from the iron? (a) it is sticky (b) it is magnetic (c) it is cold (d) it can burn skin
30. 30.True or false: an adult with an iron is needed for the secret lemon message. (a) True (b) False
31. 31.⚖️ 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
32. 32.True or false: writing the message is a job for an adult. (a) False (b) True
33. 33.True or false: a battery cell is not needed for the secret lemon message. (a) True (b) False
34. 34.True or false: white paper is needed for the secret lemon message. (a) False (b) True
35. 35.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is kept the same? (a) the kind of juice (b) the same cotton bud (c) how dark the writing is
36. 36.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the iron setting is kept the same. (a) False (b) True
37. 37.🧺 Which of these is not needed for the secret lemon message? (a) a small bowl (b) a cotton bud (c) turmeric powder (d) lemon juice
38. 38.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “how dark the writing is”? (a) we keep it the same (b) we change it (c) we measure it
39. 39.🧺 Which of these is needed for the secret lemon message? (a) yeast (b) a cotton bud (c) a balloon (d) turmeric powder
40. 40.🧺 Do we need turmeric powder for the secret lemon message? (a) not needed (b) needed

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