Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 498 · 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 turmeric powder for the secret lemon message? (a) not needed (b) needed
2. 2.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the same paper”? (a) we keep it the same (b) we change it (c) we measure it
3. 3.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) white paper (b) a magnet (c) a small bowl (d) a cotton bud
4. 4.True or false: a small bowl is needed for the secret lemon message. (a) True (b) False
5. 5.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a small bowl (b) white paper (c) a mirror (d) a cotton bud
6. 6.🍋 Secret message: who does this step — reading the message? (a) a child can do it (b) an adult does it
7. 7.🔮 Can the brown writing go back to being invisible? (a) yes, if cooled (b) yes, if shaken (c) no, it stays brown (d) yes, in the dark
8. 8.🔮 Predict: you write with plain water instead of lemon juice. What appears after ironing? (a) blue words (b) a rainbow (c) almost nothing (d) dark brown words
9. 9.🔍 Which is the odd one out? (a) cutting the lemon (b) plugging in the iron (c) dipping the cotton bud (d) ironing the paper
10. 10.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) lick your fingers (b) rub your eyes (c) wash your hands (d) skip washing
11. 11.True or false: a cotton bud is needed for the secret lemon message. (a) False (b) True
12. 12.🧺 Do we need white paper for the secret lemon message? (a) not needed (b) needed
13. 13.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the iron setting is the one thing we change. (a) False (b) True
14. 14.True or false: a battery cell is not needed for the secret lemon message. (a) True (b) False
15. 15.🍋 Secret message: who does this step — plugging in the iron? (a) an adult does it (b) a child can do it
16. 16.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the iron setting”? (a) we keep it the same (b) we measure it (c) we change it
17. 17.🧺 Which of these is needed for the secret lemon message? (a) a magnet (b) a battery cell (c) turmeric powder (d) lemon juice
18. 18.True or false: a mirror is needed for the secret lemon message. (a) False (b) True
19. 19.🍋 Secret message: who does this step — putting the iron away? (a) a child can do it (b) an adult does it
20. 20.⚖️ 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
21. 21.🧺 Do we need an adult with an iron for the secret lemon message? (a) needed (b) not needed
22. 22.🧺 Do we need lemon juice for the secret lemon message? (a) not needed (b) needed
23. 23.🧺 Which of these is needed for the secret lemon message? (a) a balloon (b) a magnet (c) turmeric powder (d) an adult with an iron
24. 24.🍋 Which of these steps is a job a child can do? (a) cutting the lemon (b) writing the message (c) putting the iron away (d) ironing the paper
25. 25.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is what we measure? (a) the ironing time (b) the iron setting (c) the same paper (d) how dark the writing is
26. 26.⚖️ 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 kind of juice (d) the iron setting
27. 27.🍋 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
28. 28.🍋 Secret message: who does this step — dipping the cotton bud? (a) an adult does it (b) a child can do it
29. 29.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the kind of juice is kept the same. (a) True (b) False
30. 30.🍋 What colour does the lemon writing turn when an adult warms it? (a) brown (b) white (c) blue (d) green
31. 31.True or false: plugging in the iron is a job for an adult. (a) False (b) True
32. 32.🔍 Which is the odd one out? (a) letting the paper dry (b) cutting the lemon (c) dipping the cotton bud (d) writing the message
33. 33.🍋 Why can’t you see the lemon writing once it dries? (a) the paper ate it (b) dry juice is see-through (c) the ink is magnetic (d) it turned into air
34. 34.🍋 Secret message: who does this step — letting the paper dry? (a) an adult does it (b) a child can do it
35. 35.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a cotton bud (b) a battery cell (c) an adult with an iron (d) white paper
36. 36.True or false: putting the iron away is a job a child can do. (a) True (b) False
37. 37.🧺 Do we need a magnet for the secret lemon message? (a) not needed (b) needed
38. 38.True or false: lemon juice is needed for the secret lemon message. (a) True (b) False
39. 39.True or false: a balloon is not needed for the secret lemon message. (a) True (b) False
40. 40.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a cotton bud (b) an adult with an iron (c) lemon juice (d) turmeric powder

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