Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 942 · 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.🍋 Secret message: who does this step — ironing the paper? (a) a child can do it (b) an adult does it
2. 2.True or false: yeast is needed for the secret lemon message. (a) False (b) True
3. 3.⚖️ 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
4. 4.🍋 Which of these steps is a job for an adult? (a) dipping the cotton bud (b) letting the paper dry (c) cutting the lemon (d) reading the message
5. 5.🍋 Secret message: who does this step — reading the message? (a) an adult does it (b) a child can do it
6. 6.🍋 Which of these steps is a job for an adult? (a) writing the message (b) ironing the paper (c) letting the paper dry (d) reading the message
7. 7.⚖️ 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 ironing time (c) the iron setting (d) the kind of juice
8. 8.🧺 Do we need a magnet 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) yeast (b) an adult with an iron (c) a small bowl (d) a cotton bud
10. 10.⚖️ 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) False (b) True
11. 11.🔍 Which is the odd one out? (a) writing the message (b) putting the iron away (c) ironing the paper (d) plugging in the iron
12. 12.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the ironing time”? (a) we change it (b) we keep it the same (c) we measure it
13. 13.🍋 Secret message: who does this step — dipping the cotton bud? (a) an adult does it (b) a child can do it
14. 14.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) skip washing (b) wash your hands (c) rub your eyes (d) lick your fingers
15. 15.🔍 Which is the odd one out? (a) reading the message (b) putting the iron away (c) letting the paper dry (d) writing the message
16. 16.🍋 Which of these steps is a job a child can do? (a) cutting the lemon (b) putting the iron away (c) letting the paper dry (d) ironing the paper
17. 17.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) turmeric powder (b) a small bowl (c) white paper (d) lemon juice
18. 18.🧺 Which of these is needed for the secret lemon message? (a) a mirror (b) white paper (c) a magnet (d) a balloon
19. 19.🧺 Which of these is needed for the secret lemon message? (a) an adult with an iron (b) a balloon (c) yeast (d) a battery cell
20. 20.🧺 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) a mirror (d) a cotton bud
21. 21.🍋 Why can’t you see the lemon writing once it dries? (a) the paper ate it (b) the ink is magnetic (c) dry juice is see-through (d) it turned into air
22. 22.🧺 Which of these is not needed for the secret lemon message? (a) a small bowl (b) lemon juice (c) white paper (d) a magnet
23. 23.True or false: yeast is not needed for the secret lemon message. (a) True (b) False
24. 24.True or false: plugging in the iron is a job for an adult. (a) True (b) False
25. 25.True or false: reading the message is a job a child can do. (a) False (b) True
26. 26.🔮 Predict: the adult irons for only one second. What happens? (a) it gets darker (b) the paper floats (c) writing stays faint (d) writing turns green
27. 27.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a battery cell (b) a small bowl (c) white paper (d) lemon juice
28. 28.⚖️ 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) True (b) False
29. 29.🍋 Which of these steps is a job a child can do? (a) writing the message (b) cutting the lemon (c) plugging in the iron (d) putting the iron away
30. 30.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) lemon juice (b) a cotton bud (c) a balloon (d) an adult with an iron
31. 31.⚖️ 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) False (b) True
32. 32.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the iron setting is what we measure. (a) True (b) False
33. 33.📘 The browning of lemon juice with heat is a ___ change. (a) musical (b) chemical (c) magnetic (d) physical
34. 34.True or false: ironing the paper is a job for an adult. (a) True (b) False
35. 35.🍋 Which of these steps is a job for an adult? (a) dipping the cotton bud (b) reading the message (c) putting the iron away (d) letting the paper dry
36. 36.True or false: a small bowl is needed for the secret lemon message. (a) False (b) True
37. 37.True or false: a magnet is needed for the secret lemon message. (a) True (b) False
38. 38.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the same cotton bud”? (a) we measure it (b) we keep it the same (c) we change it
39. 39.🧺 Which of these is not needed for the secret lemon message? (a) a small bowl (b) a balloon (c) white paper (d) lemon juice
40. 40.🧺 Do we need white paper for the secret lemon message? (a) needed (b) not needed

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