Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 255 · 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.True or false: ironing the paper is a job a child can do. (a) False (b) True
2. 2.🍋 Which of these steps is a job a child can do? (a) ironing the paper (b) letting the paper dry (c) cutting the lemon (d) plugging in the iron
3. 3.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) lemon juice (b) a small bowl (c) an adult with an iron (d) a magnet
4. 4.True or false: plugging in the iron is a job a child can do. (a) False (b) True
5. 5.⚖️ 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 same cotton bud (c) the kind of juice (d) the same paper
6. 6.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the kind of juice is the one thing we change. (a) False (b) True
7. 7.🧺 Do we need an adult with an iron for the secret lemon message? (a) not needed (b) needed
8. 8.⚖️ 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
9. 9.🍋 Which of these steps is a job for an adult? (a) reading the message (b) letting the paper dry (c) writing the message (d) cutting the lemon
10. 10.🧺 Which of these is not needed for the secret lemon message? (a) an adult with an iron (b) white paper (c) a cotton bud (d) turmeric powder
11. 11.True or false: lemon juice is not needed for the secret lemon message. (a) False (b) True
12. 12.True or false: a battery cell is not needed for the secret lemon message. (a) True (b) False
13. 13.🧺 Do we need white paper for the secret lemon message? (a) not needed (b) needed
14. 14.🔮 Can the brown writing go back to being invisible? (a) yes, if cooled (b) yes, in the dark (c) no, it stays brown (d) yes, if shaken
15. 15.True or false: a cotton bud is needed for the secret lemon message. (a) True (b) False
16. 16.True or false: cutting the lemon is a job a child can do. (a) False (b) True
17. 17.True or false: writing the message is a job a child can do. (a) False (b) True
18. 18.True or false: an adult with an iron is not needed for the secret lemon message. (a) True (b) False
19. 19.True or false: letting the paper dry is a job for an adult. (a) False (b) True
20. 20.🍋 Secret message: who does this step — dipping the cotton bud? (a) an adult does it (b) a child can do it
21. 21.🍋 Why can’t you see the lemon writing once it dries? (a) the paper ate it (b) dry juice is see-through (c) it turned into air (d) the ink is magnetic
22. 22.🍋 Which of these steps is a job a child can do? (a) writing the message (b) cutting the lemon (c) ironing the paper (d) plugging in the iron
23. 23.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a small bowl (b) a cotton bud (c) a battery cell (d) lemon juice
24. 24.🍋 Which of these steps is a job a child can do? (a) ironing the paper (b) cutting the lemon (c) putting the iron away (d) dipping the cotton bud
25. 25.🔍 Which is the odd one out? (a) plugging in the iron (b) ironing the paper (c) cutting the lemon (d) writing the message
26. 26.True or false: reading the message is a job for an adult. (a) False (b) True
27. 27.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) lemon juice (b) white paper (c) a small bowl (d) a balloon
28. 28.🛟 Why must children keep their fingers away from the iron? (a) it is sticky (b) it is magnetic (c) it can burn skin (d) it is cold
29. 29.🛟 Who should use the hot iron in the secret message experiment? (a) whoever is fastest (b) only an adult (c) the youngest child (d) any child
30. 30.🍋 Which of these steps is a job for an adult? (a) ironing the paper (b) dipping the cotton bud (c) reading the message (d) letting the paper dry
31. 31.⚖️ 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 change it (c) we measure it
32. 32.True or false: a small bowl is not needed for the secret lemon message. (a) True (b) False
33. 33.🔍 Which is the odd one out? (a) dipping the cotton bud (b) putting the iron away (c) ironing the paper (d) cutting the lemon
34. 34.🧺 Which of these is needed for the secret lemon message? (a) yeast (b) lemon juice (c) a balloon (d) a magnet
35. 35.True or false: a mirror is not needed for the secret lemon message. (a) True (b) False
36. 36.🍋 Secret message: who does this step — putting the iron away? (a) a child can do it (b) an adult does it
37. 37.🧺 Do we need yeast for the secret lemon message? (a) needed (b) not needed
38. 38.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: how dark the writing is is the one thing we change. (a) False (b) True
39. 39.⚖️ 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
40. 40.🍋 Secret message: who does this step — plugging in the iron? (a) a child can do it (b) an adult does it

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