Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 171 · 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.🧺 Do we need white paper for the secret lemon message? (a) not needed (b) needed
2. 2.🍋 Which of these steps is a job a child can do? (a) cutting the lemon (b) ironing the paper (c) letting the paper dry (d) putting the iron away
3. 3.🔍 Which is the odd one out? (a) cutting the lemon (b) dipping the cotton bud (c) reading the message (d) writing the message
4. 4.🧺 Do we need yeast for the secret lemon message? (a) needed (b) not needed
5. 5.True or false: white paper is needed for the secret lemon message. (a) False (b) True
6. 6.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is the one thing we change? (a) the iron setting (b) the kind of juice (c) the same paper (d) the same cotton bud
7. 7.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) white paper (b) a cotton bud (c) a mirror (d) a small bowl
8. 8.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) white paper (b) a magnet (c) lemon juice (d) a small bowl
9. 9.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) white paper (b) turmeric powder (c) a small bowl (d) lemon juice
10. 10.🛟 Who should use the hot iron in the secret message experiment? (a) any child (b) whoever is fastest (c) only an adult (d) the youngest child
11. 11.🍋 Secret message: who does this step — letting the paper dry? (a) a child can do it (b) an adult does it
12. 12.True or false: a magnet is needed for the secret lemon message. (a) False (b) True
13. 13.🍋 Why can’t you see the lemon writing once it dries? (a) it turned into air (b) the ink is magnetic (c) the paper ate it (d) dry juice is see-through
14. 14.⚖️ 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) how dark the writing is (c) the same cotton bud
15. 15.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the iron setting”? (a) we change it (b) we keep it the same (c) we measure it
16. 16.🧺 Do we need turmeric powder for the secret lemon message? (a) needed (b) not needed
17. 17.🍋 Which of these steps is a job for an adult? (a) dipping the cotton bud (b) letting the paper dry (c) writing the message (d) cutting the lemon
18. 18.True or false: yeast is not needed for the secret lemon message. (a) False (b) True
19. 19.🧺 Which of these is not needed for the secret lemon message? (a) turmeric powder (b) a cotton bud (c) an adult with an iron (d) lemon juice
20. 20.🍋 Secret message: who does this step — ironing the paper? (a) a child can do it (b) an adult does it
21. 21.True or false: reading the message is a job for an adult. (a) False (b) True
22. 22.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is kept the same? (a) the same paper (b) how dark the writing is (c) the kind of juice
23. 23.⚖️ 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
24. 24.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) skip washing (b) wash your hands (c) lick your fingers (d) rub your eyes
25. 25.True or false: a cotton bud is needed for the secret lemon message. (a) False (b) True
26. 26.🧺 Do we need a magnet for the secret lemon message? (a) not needed (b) needed
27. 27.📘 The browning of lemon juice with heat is a ___ change. (a) musical (b) magnetic (c) physical (d) chemical
28. 28.🍋 Which of these steps is a job for an adult? (a) ironing the paper (b) writing the message (c) reading the message (d) letting the paper dry
29. 29.🍋 Which of these steps is a job for an adult? (a) dipping the cotton bud (b) plugging in the iron (c) letting the paper dry (d) writing the message
30. 30.🍋 Secret message: who does this step — plugging in the iron? (a) a child can do it (b) an adult does it
31. 31.True or false: writing the message is a job a child can do. (a) False (b) True
32. 32.True or false: white paper is not needed for the secret lemon message. (a) True (b) False
33. 33.🔍 Which is the odd one out? (a) letting the paper dry (b) writing the message (c) ironing the paper (d) reading the message
34. 34.🔍 Which is the odd one out? (a) dipping the cotton bud (b) writing the message (c) plugging in the iron (d) letting the paper dry
35. 35.🛟 Why must children keep their fingers away from the iron? (a) it is magnetic (b) it can burn skin (c) it is sticky (d) it is cold
36. 36.True or false: plugging in the iron is a job for an adult. (a) False (b) True
37. 37.🍋 Which of these steps is a job a child can do? (a) putting the iron away (b) cutting the lemon (c) reading the message (d) plugging in the iron
38. 38.🔍 Which is the odd one out? (a) cutting the lemon (b) reading the message (c) ironing the paper (d) plugging in the iron
39. 39.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the same paper is kept the same. (a) True (b) False
40. 40.🍋 Secret message: who does this step — reading the message? (a) a child can do it (b) an adult does it

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