Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 333 · 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 is not needed for the secret lemon message? (a) an adult with an iron (b) lemon juice (c) a cotton bud (d) a battery cell
2. 2.🧺 Do we need a battery cell for the secret lemon message? (a) not needed (b) needed
3. 3.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is kept the same? (a) the same cotton bud (b) the kind of juice (c) how dark the writing is
4. 4.True or false: ironing the paper is a job for an adult. (a) True (b) False
5. 5.🍋 Secret message: who does this step — writing the message? (a) an adult does it (b) a child can do it
6. 6.🍋 Secret message: who does this step — ironing the paper? (a) an adult does it (b) a child can do it
7. 7.🍋 Secret message: who does this step — cutting the lemon? (a) an adult does it (b) a child can do it
8. 8.📘 The browning of lemon juice with heat is a ___ change. (a) magnetic (b) musical (c) physical (d) chemical
9. 9.⚖️ 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
10. 10.🧺 Which of these is not needed for the secret lemon message? (a) white paper (b) a cotton bud (c) lemon juice (d) a balloon
11. 11.🧺 Do we need a mirror for the secret lemon message? (a) not needed (b) needed
12. 12.🛟 Who should use the hot iron in the secret message experiment? (a) the youngest child (b) whoever is fastest (c) only an adult (d) any child
13. 13.🧺 Which of these is not needed for the secret lemon message? (a) a small bowl (b) a magnet (c) an adult with an iron (d) lemon juice
14. 14.🧺 Which of these is needed for the secret lemon message? (a) yeast (b) a mirror (c) turmeric powder (d) a cotton bud
15. 15.True or false: letting the paper dry is a job for an adult. (a) True (b) False
16. 16.True or false: a mirror is not needed for the secret lemon message. (a) True (b) False
17. 17.🧺 Which of these is not needed for the secret lemon message? (a) an adult with an iron (b) a small bowl (c) turmeric powder (d) a cotton bud
18. 18.True or false: a small bowl is not needed for the secret lemon message. (a) True (b) False
19. 19.🔍 Which is the odd one out? (a) cutting the lemon (b) ironing the paper (c) plugging in the iron (d) dipping the cotton bud
20. 20.🍋 Which of these steps is a job a child can do? (a) ironing the paper (b) plugging in the iron (c) writing the message (d) cutting the lemon
21. 21.True or false: a battery cell is needed for the secret lemon message. (a) False (b) True
22. 22.True or false: turmeric powder is not needed for the secret lemon message. (a) True (b) False
23. 23.🔍 Which is the odd one out? (a) plugging in the iron (b) cutting the lemon (c) putting the iron away (d) writing the message
24. 24.🍋 Secret message: who does this step — dipping the cotton bud? (a) an adult does it (b) a child can do it
25. 25.🧺 Do we need turmeric powder for the secret lemon message? (a) needed (b) not needed
26. 26.⚖️ 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
27. 27.🍋 Secret message: who does this step — reading the message? (a) a child can do it (b) an adult does it
28. 28.🧺 Do we need white paper for the secret lemon message? (a) not needed (b) needed
29. 29.⚖️ 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 measure it (c) we change it
30. 30.True or false: dipping the cotton bud is a job a child can do. (a) True (b) False
31. 31.⚖️ 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
32. 32.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the ironing time is the one thing we change. (a) True (b) False
33. 33.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is kept the same? (a) the same paper (b) how dark the writing is (c) the kind of juice
34. 34.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is the one thing we change? (a) how dark the writing is (b) the kind of juice (c) the iron setting (d) the same cotton bud
35. 35.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the same paper”? (a) we keep it the same (b) we measure it (c) we change it
36. 36.True or false: plugging in the iron is a job for an adult. (a) False (b) True
37. 37.True or false: yeast is not needed for the secret lemon message. (a) False (b) True
38. 38.🔍 Which is the odd one out? (a) writing the message (b) letting the paper dry (c) reading the message (d) ironing the paper
39. 39.🔍 Which is the odd one out? (a) reading the message (b) dipping the cotton bud (c) putting the iron away (d) writing the message
40. 40.🛟 Why must children keep their fingers away from the iron? (a) it is sticky (b) it can burn skin (c) it is cold (d) it is magnetic

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