Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 619 · 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 steps is a job for an adult? (a) putting the iron away (b) reading the message (c) letting the paper dry (d) dipping the cotton bud
2. 2.🔮 Predict: the adult irons for only one second. What happens? (a) writing turns green (b) the paper floats (c) it gets darker (d) writing stays faint
3. 3.🍋 Secret message: who does this step — plugging in the iron? (a) an adult does it (b) a child can do it
4. 4.🍋 Which of these steps is a job a child can do? (a) reading the message (b) ironing the paper (c) putting the iron away (d) cutting the lemon
5. 5.🔍 Which is the odd one out? (a) putting the iron away (b) plugging in the iron (c) ironing the paper (d) letting the paper dry
6. 6.🛟 Who should use the hot iron in the secret message experiment? (a) whoever is fastest (b) only an adult (c) the youngest child (d) any child
7. 7.🍋 Which of these steps is a job a child can do? (a) ironing the paper (b) putting the iron away (c) dipping the cotton bud (d) plugging in the iron
8. 8.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) skip washing (b) lick your fingers (c) wash your hands (d) rub your eyes
9. 9.True or false: a balloon is needed for the secret lemon message. (a) True (b) False
10. 10.True or false: a cotton bud is not needed for the secret lemon message. (a) True (b) False
11. 11.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the same paper”? (a) we measure it (b) we change it (c) we keep it the same
12. 12.🧺 Do we need white paper for the secret lemon message? (a) needed (b) not needed
13. 13.🧺 Do we need a magnet for the secret lemon message? (a) not needed (b) needed
14. 14.🔮 Predict: you write with plain water instead of lemon juice. What appears after ironing? (a) blue words (b) dark brown words (c) almost nothing (d) a rainbow
15. 15.True or false: plugging in the iron is a job for an adult. (a) False (b) True
16. 16.True or false: plugging in the iron is a job a child can do. (a) True (b) False
17. 17.🧺 Which of these is not needed for the secret lemon message? (a) a cotton bud (b) a battery cell (c) a small bowl (d) lemon juice
18. 18.🧺 Do we need turmeric powder for the secret lemon message? (a) needed (b) not needed
19. 19.⚖️ 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
20. 20.⚖️ 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 same paper (c) the iron setting (d) the kind of juice
21. 21.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) lemon juice (b) turmeric powder (c) an adult with an iron (d) a cotton bud
22. 22.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “how dark the writing is”? (a) we measure it (b) we keep it the same (c) we change it
23. 23.🍋 Which of these steps is a job a child can do? (a) ironing the paper (b) plugging in the iron (c) letting the paper dry (d) cutting the lemon
24. 24.⚖️ 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 keep it the same (c) we measure it
25. 25.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the ironing time”? (a) we keep it the same (b) we change it (c) we measure it
26. 26.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a cotton bud (b) lemon juice (c) a mirror (d) a small bowl
27. 27.🧺 Which of these is not needed for the secret lemon message? (a) lemon juice (b) a balloon (c) a small bowl (d) white paper
28. 28.🧺 Which of these is needed for the secret lemon message? (a) a battery cell (b) a magnet (c) turmeric powder (d) an adult with an iron
29. 29.🔍 Which is the odd one out? (a) reading the message (b) ironing the paper (c) letting the paper dry (d) writing the message
30. 30.⚖️ 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
31. 31.🧺 Which of these is not needed for the secret lemon message? (a) a small bowl (b) yeast (c) white paper (d) lemon juice
32. 32.🧺 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) white paper (d) a magnet
33. 33.🍋 What colour does the lemon writing turn when an adult warms it? (a) blue (b) green (c) white (d) brown
34. 34.True or false: yeast is not needed for the secret lemon message. (a) True (b) False
35. 35.🍋 Secret message: who does this step — ironing the paper? (a) a child can do it (b) an adult does it
36. 36.🧺 Do we need lemon juice for the secret lemon message? (a) needed (b) not needed
37. 37.🍋 Why can’t you see the lemon writing once it dries? (a) it turned into air (b) the paper ate it (c) dry juice is see-through (d) the ink is magnetic
38. 38.🛟 Why must children keep their fingers away from the iron? (a) it is sticky (b) it is magnetic (c) it is cold (d) it can burn skin
39. 39.True or false: yeast is needed for the secret lemon message. (a) False (b) True
40. 40.🍋 Which of these steps is a job for an adult? (a) letting the paper dry (b) dipping the cotton bud (c) reading the message (d) plugging in the iron

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