Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 577 · 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? Which of these is the one thing we change? (a) the ironing time (b) how dark the writing is (c) the iron setting (d) the kind of juice
2. 2.🍋 Which of these steps is a job a child can do? (a) writing the message (b) ironing the paper (c) cutting the lemon (d) plugging in the iron
3. 3.⚖️ 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
4. 4.🧺 Do we need yeast for the secret lemon message? (a) not needed (b) needed
5. 5.🧺 Which of these is not needed for the secret lemon message? (a) white paper (b) a mirror (c) a cotton bud (d) an adult with an iron
6. 6.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the iron setting is what we measure. (a) False (b) True
7. 7.⚖️ 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 same paper (d) the kind of juice
8. 8.🛟 Who should use the hot iron in the secret message experiment? (a) the youngest child (b) any child (c) only an adult (d) whoever is fastest
9. 9.🍋 Why can’t you see the lemon writing once it dries? (a) it turned into air (b) the ink is magnetic (c) dry juice is see-through (d) the paper ate it
10. 10.🍋 Which of these steps is a job for an adult? (a) writing the message (b) dipping the cotton bud (c) ironing the paper (d) letting the paper dry
11. 11.⚖️ 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
12. 12.True or false: a cotton bud is needed for the secret lemon message. (a) True (b) False
13. 13.🍋 Which of these steps is a job for an adult? (a) letting the paper dry (b) reading the message (c) dipping the cotton bud (d) cutting the lemon
14. 14.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) an adult with an iron (b) white paper (c) turmeric powder (d) a small bowl
15. 15.True or false: dipping the cotton bud is a job a child can do. (a) True (b) False
16. 16.🧺 Which of these is needed for the secret lemon message? (a) turmeric powder (b) a battery cell (c) yeast (d) an adult with an iron
17. 17.🔮 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
18. 18.True or false: letting the paper dry is a job for an adult. (a) False (b) True
19. 19.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: how dark the writing is is kept the same. (a) True (b) False
20. 20.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) an adult with an iron (b) a small bowl (c) a mirror (d) lemon juice
21. 21.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a small bowl (b) a cotton bud (c) white paper (d) a magnet
22. 22.🍋 Secret message: who does this step — plugging in the iron? (a) a child can do it (b) an adult does it
23. 23.🔍 Which is the odd one out? (a) cutting the lemon (b) ironing the paper (c) plugging in the iron (d) reading the message
24. 24.🧺 Which of these is not needed for the secret lemon message? (a) a cotton bud (b) a small bowl (c) an adult with an iron (d) a balloon
25. 25.True or false: ironing the paper is a job for an adult. (a) False (b) True
26. 26.🍋 Secret message: who does this step — ironing the paper? (a) an adult does it (b) a child can do it
27. 27.🧺 Which of these is not needed for the secret lemon message? (a) a cotton bud (b) lemon juice (c) yeast (d) an adult with an iron
28. 28.🧺 Which of these is needed for the secret lemon message? (a) a small bowl (b) a battery cell (c) a magnet (d) yeast
29. 29.True or false: letting the paper dry is a job a child can do. (a) False (b) True
30. 30.🍋 Which of these steps is a job a child can do? (a) putting the iron away (b) dipping the cotton bud (c) cutting the lemon (d) ironing the paper
31. 31.True or false: lemon juice is not needed for the secret lemon message. (a) True (b) False
32. 32.🧺 Which of these is not needed for the secret lemon message? (a) a cotton bud (b) lemon juice (c) a battery cell (d) white paper
33. 33.🍋 Which of these steps is a job for an adult? (a) letting the paper dry (b) plugging in the iron (c) dipping the cotton bud (d) writing the message
34. 34.🧺 Do we need a small bowl for the secret lemon message? (a) needed (b) not needed
35. 35.🔍 Which is the odd one out? (a) reading the message (b) cutting the lemon (c) letting the paper dry (d) writing the message
36. 36.⚖️ 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 measure it (c) we change it
37. 37.🧺 Which of these is needed for the secret lemon message? (a) turmeric powder (b) a balloon (c) a cotton bud (d) a magnet
38. 38.🍋 Which of these steps is a job a child can do? (a) letting the paper dry (b) cutting the lemon (c) ironing the paper (d) putting the iron away
39. 39.🍋 Secret message: who does this step — dipping the cotton bud? (a) a child can do it (b) an adult does it
40. 40.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is kept the same? (a) how dark the writing is (b) the kind of juice (c) the same paper

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