Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 482 · 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 needed for the secret lemon message? (a) a magnet (b) white paper (c) a battery cell (d) yeast
2. 2.🛟 Why must children keep their fingers away from the iron? (a) it can burn skin (b) it is sticky (c) it is cold (d) it is magnetic
3. 3.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a balloon (b) a small bowl (c) an adult with an iron (d) white paper
4. 4.🧺 Which of these is not needed for the secret lemon message? (a) a mirror (b) white paper (c) a cotton bud (d) a small bowl
5. 5.True or false: ironing the paper is a job a child can do. (a) False (b) True
6. 6.🔍 Which is the odd one out? (a) writing the message (b) ironing the paper (c) cutting the lemon (d) putting the iron away
7. 7.🛟 Who should use the hot iron in the secret message experiment? (a) only an adult (b) whoever is fastest (c) any child (d) the youngest child
8. 8.🍋 Which of these steps is a job for an adult? (a) dipping the cotton bud (b) letting the paper dry (c) reading the message (d) ironing the paper
9. 9.True or false: reading the message is a job a child can do. (a) False (b) True
10. 10.True or false: white paper is needed for the secret lemon message. (a) False (b) True
11. 11.True or false: a battery cell is needed for the secret lemon message. (a) True (b) False
12. 12.True or false: white paper is not needed for the secret lemon message. (a) False (b) True
13. 13.🧺 Do we need a small bowl for the secret lemon message? (a) needed (b) not needed
14. 14.🧺 Which of these is needed for the secret lemon message? (a) a battery cell (b) an adult with an iron (c) turmeric powder (d) a magnet
15. 15.🍋 Secret message: who does this step — dipping the cotton bud? (a) a child can do it (b) an adult does it
16. 16.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the same paper is what we measure. (a) False (b) True
17. 17.🧺 Do we need white paper for the secret lemon message? (a) not needed (b) needed
18. 18.True or false: putting the iron away is a job for an adult. (a) True (b) False
19. 19.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the ironing time”? (a) we measure it (b) we keep it the same (c) we change it
20. 20.🔍 Which is the odd one out? (a) dipping the cotton bud (b) letting the paper dry (c) cutting the lemon (d) reading the message
21. 21.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the iron setting”? (a) we measure it (b) we change it (c) we keep it the same
22. 22.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the same cotton bud”? (a) we change it (b) we measure it (c) we keep it the same
23. 23.⚖️ 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
24. 24.🔮 Can the brown writing go back to being invisible? (a) yes, in the dark (b) no, it stays brown (c) yes, if shaken (d) yes, if cooled
25. 25.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the same paper is kept the same. (a) False (b) True
26. 26.🍋 Secret message: who does this step — writing the message? (a) an adult does it (b) a child can do it
27. 27.⚖️ 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 same paper (c) how dark the writing is
28. 28.🍋 Secret message: who does this step — ironing the paper? (a) a child can do it (b) an adult does it
29. 29.⚖️ 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) False (b) True
30. 30.🧺 Do we need a battery cell for the secret lemon message? (a) not needed (b) needed
31. 31.🔮 Predict: the adult irons for only one second. What happens? (a) writing turns green (b) writing stays faint (c) it gets darker (d) the paper floats
32. 32.🍋 Which of these steps is a job for an adult? (a) letting the paper dry (b) reading the message (c) plugging in the iron (d) dipping the cotton bud
33. 33.🔍 Which is the odd one out? (a) cutting the lemon (b) plugging in the iron (c) dipping the cotton bud (d) ironing the paper
34. 34.🧺 Which of these is not needed for the secret lemon message? (a) yeast (b) lemon juice (c) a small bowl (d) white paper
35. 35.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: how dark the writing is is what we measure. (a) True (b) False
36. 36.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a mirror (b) an adult with an iron (c) white paper (d) a cotton bud
37. 37.🍋 Secret message: who does this step — letting the paper dry? (a) a child can do it (b) an adult does it
38. 38.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the kind of juice is what we measure. (a) True (b) False
39. 39.🍋 Secret message: who does this step — cutting the lemon? (a) a child can do it (b) an adult does it
40. 40.🍋 What colour does the lemon writing turn when an adult warms it? (a) green (b) blue (c) white (d) brown

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