Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 703 · 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.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a cotton bud (b) a small bowl (c) a battery cell (d) white paper
2. 2.🍋 What colour does the lemon writing turn when an adult warms it? (a) green (b) blue (c) white (d) brown
3. 3.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) an adult with an iron (b) a magnet (c) a cotton bud (d) lemon juice
4. 4.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) an adult with an iron (b) a small bowl (c) white paper (d) yeast
5. 5.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) lemon juice (b) an adult with an iron (c) a small bowl (d) a balloon
6. 6.True or false: a battery cell is not needed for the secret lemon message. (a) False (b) True
7. 7.🛟 Who should use the hot iron in the secret message experiment? (a) the youngest child (b) whoever is fastest (c) only an adult (d) any child
8. 8.🧺 Which of these is needed for the secret lemon message? (a) a balloon (b) a magnet (c) an adult with an iron (d) a battery cell
9. 9.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) wash your hands (b) lick your fingers (c) rub your eyes (d) skip washing
10. 10.🍋 Which of these steps is a job for an adult? (a) reading the message (b) cutting the lemon (c) letting the paper dry (d) dipping the cotton bud
11. 11.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is the one thing we change? (a) the same paper (b) how dark the writing is (c) the iron setting (d) the kind of juice
12. 12.⚖️ 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 keep it the same (c) we measure it
13. 13.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the same paper”? (a) we change it (b) we keep it the same (c) we measure it
14. 14.⚖️ 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
15. 15.True or false: reading the message is a job for an adult. (a) False (b) True
16. 16.True or false: turmeric powder is needed for the secret lemon message. (a) True (b) False
17. 17.🔮 Predict: you write with plain water instead of lemon juice. What appears after ironing? (a) a rainbow (b) blue words (c) almost nothing (d) dark brown words
18. 18.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is what we measure? (a) the kind of juice (b) the iron setting (c) the same paper (d) how dark the writing is
19. 19.⚖️ 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
20. 20.🧺 Do we need a magnet for the secret lemon message? (a) needed (b) not needed
21. 21.🍋 Secret message: who does this step — putting the iron away? (a) an adult does it (b) a child can do it
22. 22.🔍 Which is the odd one out? (a) ironing the paper (b) plugging in the iron (c) reading the message (d) cutting the lemon
23. 23.🍋 Which of these steps is a job for an adult? (a) writing the message (b) plugging in the iron (c) reading the message (d) dipping the cotton bud
24. 24.🍋 Secret message: who does this step — ironing the paper? (a) a child can do it (b) an adult does it
25. 25.🍋 Why can’t you see the lemon writing once it dries? (a) the ink is magnetic (b) the paper ate it (c) dry juice is see-through (d) it turned into air
26. 26.🛟 Why must children keep their fingers away from the iron? (a) it can burn skin (b) it is magnetic (c) it is sticky (d) it is cold
27. 27.🔍 Which is the odd one out? (a) putting the iron away (b) letting the paper dry (c) reading the message (d) dipping the cotton bud
28. 28.🍋 Secret message: who does this step — writing the message? (a) an adult does it (b) a child can do it
29. 29.🧺 Which of these is needed for the secret lemon message? (a) turmeric powder (b) a mirror (c) white paper (d) a balloon
30. 30.🍋 Secret message: who does this step — cutting the lemon? (a) a child can do it (b) an adult does it
31. 31.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a cotton bud (b) white paper (c) a small bowl (d) a mirror
32. 32.🍋 Which of these steps is a job a child can do? (a) ironing the paper (b) cutting the lemon (c) writing the message (d) putting the iron away
33. 33.🧺 Do we need turmeric powder for the secret lemon message? (a) needed (b) not needed
34. 34.⚖️ 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
35. 35.True or false: dipping the cotton bud is a job a child can do. (a) False (b) True
36. 36.🧺 Which of these is not needed for the secret lemon message? (a) a small bowl (b) an adult with an iron (c) yeast (d) white paper
37. 37.🧺 Do we need an adult with an iron for the secret lemon message? (a) not needed (b) needed
38. 38.🍋 Which of these steps is a job a child can do? (a) cutting the lemon (b) ironing the paper (c) dipping the cotton bud (d) plugging in the iron
39. 39.True or false: turmeric powder is not needed for the secret lemon message. (a) True (b) False
40. 40.🔍 Which is the odd one out? (a) dipping the cotton bud (b) letting the paper dry (c) cutting the lemon (d) writing the message

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