Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 430 · 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 for an adult? (a) putting the iron away (b) letting the paper dry (c) dipping the cotton bud (d) reading the message
2. 2.🧺 Do we need lemon juice for the secret lemon message? (a) needed (b) not needed
3. 3.True or false: dipping the cotton bud is a job for an adult. (a) False (b) True
4. 4.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a small bowl (b) turmeric powder (c) lemon juice (d) an adult with an iron
5. 5.True or false: plugging in the iron is a job a child can do. (a) False (b) True
6. 6.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) lick your fingers (b) rub your eyes (c) skip washing (d) wash your hands
7. 7.True or false: ironing the paper is a job a child can do. (a) True (b) False
8. 8.True or false: a small bowl is not needed for the secret lemon message. (a) True (b) False
9. 9.🧺 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
10. 10.True or false: letting the paper dry is a job for an adult. (a) False (b) True
11. 11.🍋 Why can’t you see the lemon writing once it dries? (a) the ink is magnetic (b) dry juice is see-through (c) the paper ate it (d) it turned into air
12. 12.🔍 Which is the odd one out? (a) putting the iron away (b) ironing the paper (c) letting the paper dry (d) plugging in the iron
13. 13.True or false: an adult with an iron is needed for the secret lemon message. (a) True (b) False
14. 14.⚖️ 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
15. 15.🧺 Do we need white paper for the secret lemon message? (a) needed (b) not needed
16. 16.🧺 Do we need a cotton bud for the secret lemon message? (a) needed (b) not needed
17. 17.🔍 Which is the odd one out? (a) cutting the lemon (b) writing the message (c) dipping the cotton bud (d) reading the message
18. 18.True or false: white paper is not needed for the secret lemon message. (a) True (b) False
19. 19.⚖️ 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 measure it (c) we change it
20. 20.🛟 Who should use the hot iron in the secret message experiment? (a) any child (b) the youngest child (c) only an adult (d) whoever is fastest
21. 21.🧺 Do we need yeast for the secret lemon message? (a) not needed (b) needed
22. 22.⚖️ 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 ironing time (c) how dark the writing is
23. 23.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) white paper (b) a cotton bud (c) an adult with an iron (d) a mirror
24. 24.True or false: cutting the lemon is a job a child can do. (a) False (b) True
25. 25.True or false: putting the iron away is a job a child can do. (a) False (b) True
26. 26.True or false: a mirror is needed for the secret lemon message. (a) False (b) True
27. 27.🍋 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) plugging in the iron
28. 28.📘 The browning of lemon juice with heat is a ___ change. (a) physical (b) musical (c) magnetic (d) chemical
29. 29.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the kind of juice is what we measure. (a) False (b) True
30. 30.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a battery cell (b) white paper (c) an adult with an iron (d) lemon juice
31. 31.True or false: a battery cell is needed for the secret lemon message. (a) False (b) True
32. 32.True or false: plugging in the iron is a job for an adult. (a) False (b) True
33. 33.🍋 Which of these steps is a job a child can do? (a) ironing the paper (b) writing the message (c) plugging in the iron (d) cutting the lemon
34. 34.🔍 Which is the odd one out? (a) reading the message (b) writing the message (c) ironing the paper (d) dipping the cotton bud
35. 35.🧺 Do we need an adult with an iron for the secret lemon message? (a) not needed (b) needed
36. 36.🍋 Secret message: who does this step — ironing the paper? (a) an adult does it (b) a child can do it
37. 37.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a balloon (b) a small bowl (c) a cotton bud (d) lemon juice
38. 38.🧺 Do we need a balloon for the secret lemon message? (a) not needed (b) needed
39. 39.🍋 Which of these steps is a job for an adult? (a) dipping the cotton bud (b) reading the message (c) ironing the paper (d) letting the paper dry
40. 40.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) lemon juice (b) a small bowl (c) a magnet (d) white paper

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