Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 69 · 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.🔮 Predict: the adult irons for only one second. What happens? (a) writing turns green (b) it gets darker (c) writing stays faint (d) the paper floats
2. 2.🧺 Do we need an adult with an iron for the secret lemon message? (a) needed (b) not needed
3. 3.🔍 Which is the odd one out? (a) cutting the lemon (b) putting the iron away (c) reading the message (d) ironing the paper
4. 4.🍋 Secret message: who does this step — plugging in the iron? (a) a child can do it (b) an adult does it
5. 5.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) an adult with an iron (b) lemon juice (c) white paper (d) a battery cell
6. 6.True or false: dipping the cotton bud is a job a child can do. (a) True (b) False
7. 7.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a small bowl (b) a cotton bud (c) white paper (d) a mirror
8. 8.🧺 Do we need a balloon for the secret lemon message? (a) needed (b) not needed
9. 9.🧺 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
10. 10.🔮 Predict: you write with plain water instead of lemon juice. What appears after ironing? (a) almost nothing (b) dark brown words (c) blue words (d) a rainbow
11. 11.🧺 Which of these is needed for the secret lemon message? (a) a cotton bud (b) a balloon (c) a magnet (d) turmeric powder
12. 12.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is what we measure? (a) the iron setting (b) the same cotton bud (c) how dark the writing is (d) the kind of juice
13. 13.🍋 Secret message: who does this step — letting the paper dry? (a) an adult does it (b) a child can do it
14. 14.🍋 Secret message: who does this step — putting the iron away? (a) an adult does it (b) a child can do it
15. 15.True or false: dipping the cotton bud is a job for an adult. (a) False (b) True
16. 16.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a small bowl (b) an adult with an iron (c) yeast (d) a cotton bud
17. 17.🧺 Do we need a mirror for the secret lemon message? (a) needed (b) not needed
18. 18.🔍 Which is the odd one out? (a) putting the iron away (b) ironing the paper (c) dipping the cotton bud (d) plugging in the iron
19. 19.🍋 Secret message: who does this step — dipping the cotton bud? (a) an adult does it (b) a child can do it
20. 20.True or false: plugging in the iron is a job a child can do. (a) True (b) False
21. 21.🍋 Secret message: who does this step — cutting the lemon? (a) an adult does it (b) a child can do it
22. 22.⚖️ 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
23. 23.🧺 Which of these is needed for the secret lemon message? (a) a balloon (b) white paper (c) a mirror (d) a battery cell
24. 24.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) lick your fingers (b) rub your eyes (c) wash your hands (d) skip washing
25. 25.🍋 Which of these steps is a job for an adult? (a) writing the message (b) cutting the lemon (c) reading the message (d) letting the paper dry
26. 26.True or false: a mirror is not needed for the secret lemon message. (a) False (b) True
27. 27.⚖️ 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 cotton bud
28. 28.🧺 Which of these is not needed for the secret lemon message? (a) a small bowl (b) white paper (c) a cotton bud (d) a magnet
29. 29.True or false: a mirror is needed for the secret lemon message. (a) False (b) True
30. 30.🔍 Which is the odd one out? (a) cutting the lemon (b) plugging in the iron (c) putting the iron away (d) writing the message
31. 31.🛟 Who should use the hot iron in the secret message experiment? (a) the youngest child (b) any child (c) only an adult (d) whoever is fastest
32. 32.🧺 Do we need a small bowl for the secret lemon message? (a) not needed (b) needed
33. 33.🍋 Which of these steps is a job for an adult? (a) writing the message (b) letting the paper dry (c) plugging in the iron (d) dipping the cotton bud
34. 34.🧺 Do we need a battery cell for the secret lemon message? (a) needed (b) not needed
35. 35.True or false: turmeric powder is needed for the secret lemon message. (a) False (b) True
36. 36.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) lemon juice (b) a cotton bud (c) white paper (d) turmeric powder
37. 37.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the kind of juice”? (a) we change it (b) we measure it (c) we keep it the same
38. 38.🧺 Do we need white paper for the secret lemon message? (a) needed (b) not needed
39. 39.🔍 Which is the odd one out? (a) dipping the cotton bud (b) putting the iron away (c) reading the message (d) letting the paper dry
40. 40.🧺 Which of these is needed for the secret lemon message? (a) a magnet (b) a mirror (c) turmeric powder (d) an adult with an iron

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