Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 828 · 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 not needed for the secret lemon message? (a) lemon juice (b) an adult with an iron (c) a mirror (d) a cotton bud
2. 2.True or false: a small bowl is not needed for the secret lemon message. (a) False (b) True
3. 3.True or false: ironing the paper is a job a child can do. (a) True (b) False
4. 4.True or false: a cotton bud is not needed for the secret lemon message. (a) True (b) False
5. 5.🛟 Why must children keep their fingers away from the iron? (a) it is cold (b) it is magnetic (c) it is sticky (d) it can burn skin
6. 6.True or false: writing the message is a job for an adult. (a) False (b) True
7. 7.🔮 Predict: the adult irons for only one second. What happens? (a) writing stays faint (b) it gets darker (c) writing turns green (d) the paper floats
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.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) lemon juice (b) a small bowl (c) a cotton bud (d) a balloon
10. 10.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the iron setting is kept the same. (a) False (b) True
11. 11.🔍 Which is the odd one out? (a) writing the message (b) reading the message (c) letting the paper dry (d) putting the iron away
12. 12.🍋 Secret message: who does this step — plugging in the iron? (a) an adult does it (b) a child can do it
13. 13.🧺 Do we need yeast for the secret lemon message? (a) needed (b) not needed
14. 14.🔍 Which is the odd one out? (a) cutting the lemon (b) putting the iron away (c) writing the message (d) ironing the paper
15. 15.📘 The browning of lemon juice with heat is a ___ change. (a) physical (b) musical (c) chemical (d) magnetic
16. 16.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) an adult with an iron (b) white paper (c) a small bowl (d) yeast
17. 17.⚖️ 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 ironing time
18. 18.True or false: plugging in the iron is a job for an adult. (a) True (b) False
19. 19.🧺 Do we need turmeric powder for the secret lemon message? (a) not needed (b) needed
20. 20.🔍 Which is the odd one out? (a) putting the iron away (b) plugging in the iron (c) dipping the cotton bud (d) cutting the lemon
21. 21.🍋 Which of these steps is a job a child can do? (a) ironing the paper (b) putting the iron away (c) letting the paper dry (d) plugging in the iron
22. 22.🧺 Which of these is not needed for the secret lemon message? (a) an adult with an iron (b) turmeric powder (c) a cotton bud (d) white paper
23. 23.🧺 Do we need a balloon for the secret lemon message? (a) needed (b) not needed
24. 24.🧺 Do we need an adult with an iron for the secret lemon message? (a) not needed (b) needed
25. 25.🧺 Do we need a mirror for the secret lemon message? (a) not needed (b) needed
26. 26.True or false: putting the iron away is a job for an adult. (a) True (b) False
27. 27.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is kept the same? (a) the same paper (b) the kind of juice (c) how dark the writing is
28. 28.🧺 Do we need a cotton bud for the secret lemon message? (a) not needed (b) needed
29. 29.True or false: plugging in the iron is a job a child can do. (a) True (b) False
30. 30.🔍 Which is the odd one out? (a) plugging in the iron (b) letting the paper dry (c) putting the iron away (d) cutting the lemon
31. 31.⚖️ 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 kind of juice (c) the same paper (d) the ironing time
32. 32.🍋 Secret message: who does this step — ironing the paper? (a) a child can do it (b) an adult does it
33. 33.🍋 Secret message: who does this step — cutting the lemon? (a) an adult does it (b) a child can do it
34. 34.🧺 Which of these is needed for the secret lemon message? (a) a magnet (b) turmeric powder (c) a balloon (d) an adult with an iron
35. 35.🧺 Which of these is not needed for the secret lemon message? (a) a cotton bud (b) white paper (c) a balloon (d) a small bowl
36. 36.🧺 Which of these is needed for the secret lemon message? (a) a balloon (b) a cotton bud (c) turmeric powder (d) yeast
37. 37.🍋 Why can’t you see the lemon writing once it dries? (a) the paper ate it (b) it turned into air (c) dry juice is see-through (d) the ink is magnetic
38. 38.⚖️ 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
39. 39.🧺 Do we need lemon juice for the secret lemon message? (a) needed (b) not needed
40. 40.🛟 Who should use the hot iron in the secret message experiment? (a) any child (b) the youngest child (c) only an adult (d) whoever is fastest

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