Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 679 · 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 mirror (b) lemon juice (c) a small bowl (d) white paper
2. 2.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is what we measure? (a) the ironing time (b) the kind of juice (c) the same cotton bud (d) how dark the writing is
3. 3.🧺 Which of these is needed for the secret lemon message? (a) a mirror (b) turmeric powder (c) lemon juice (d) a balloon
4. 4.🛟 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
5. 5.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a small bowl (b) a magnet (c) an adult with an iron (d) lemon juice
6. 6.True or false: a mirror is needed for the secret lemon message. (a) True (b) False
7. 7.🧺 Do we need turmeric powder for the secret lemon message? (a) needed (b) not needed
8. 8.🍋 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) writing the message
9. 9.🛟 Why must children keep their fingers away from the iron? (a) it is magnetic (b) it is cold (c) it is sticky (d) it can burn skin
10. 10.🍋 Which of these steps is a job for an adult? (a) ironing the paper (b) reading the message (c) writing the message (d) dipping the cotton bud
11. 11.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) white paper (b) a cotton bud (c) a balloon (d) lemon juice
12. 12.🍋 Which of these steps is a job for an adult? (a) dipping the cotton bud (b) reading the message (c) writing the message (d) cutting the lemon
13. 13.🍋 Which of these steps is a job a child can do? (a) putting the iron away (b) letting the paper dry (c) plugging in the iron (d) cutting the lemon
14. 14.True or false: a magnet is not needed for the secret lemon message. (a) False (b) True
15. 15.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the same paper”? (a) we measure it (b) we keep it the same (c) we change it
16. 16.🍋 Secret message: who does this step — cutting the lemon? (a) an adult does it (b) a child can do it
17. 17.True or false: writing the message is a job a child can do. (a) False (b) True
18. 18.🍋 Secret message: who does this step — plugging in the iron? (a) an adult does it (b) a child can do it
19. 19.⚖️ 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 iron setting (c) how dark the writing is
20. 20.📘 The browning of lemon juice with heat is a ___ change. (a) musical (b) chemical (c) magnetic (d) physical
21. 21.True or false: a small bowl is needed for the secret lemon message. (a) False (b) True
22. 22.🍋 Why can’t you see the lemon writing once it dries? (a) the paper ate it (b) it turned into air (c) dry juice is see-through (d) the ink is magnetic
23. 23.True or false: dipping the cotton bud is a job for an adult. (a) False (b) True
24. 24.True or false: cutting the lemon is a job for an adult. (a) False (b) True
25. 25.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the ironing time is what we measure. (a) False (b) True
26. 26.🧺 Which of these is needed for the secret lemon message? (a) yeast (b) a battery cell (c) a mirror (d) white paper
27. 27.🧺 Which of these is needed for the secret lemon message? (a) a magnet (b) an adult with an iron (c) a balloon (d) turmeric powder
28. 28.🧺 Which of these is not needed for the secret lemon message? (a) a cotton bud (b) a small bowl (c) a battery cell (d) white paper
29. 29.⚖️ 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
30. 30.🍋 Why does the lemon writing turn brown with heat? (a) heat adds colour (b) the iron is brown (c) paper turns lemony (d) the juice scorches first
31. 31.True or false: a balloon is needed for the secret lemon message. (a) True (b) False
32. 32.🍋 Secret message: who does this step — writing the message? (a) an adult does it (b) a child can do it
33. 33.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) turmeric powder (b) white paper (c) a small bowl (d) lemon juice
34. 34.True or false: a small bowl is not needed for the secret lemon message. (a) True (b) False
35. 35.🍋 Secret message: who does this step — letting the paper dry? (a) a child can do it (b) an adult does it
36. 36.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) white paper (b) a battery cell (c) a cotton bud (d) lemon juice
37. 37.True or false: cutting the lemon is a job a child can do. (a) False (b) True
38. 38.True or false: yeast is needed for the secret lemon message. (a) False (b) True
39. 39.🧺 Do we need a balloon for the secret lemon message? (a) needed (b) not needed
40. 40.🍋 Secret message: who does this step — ironing the paper? (a) an adult does it (b) a child can do it

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