Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 827 · 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 needed for the secret lemon message? (a) a magnet (b) a mirror (c) yeast (d) lemon juice
2. 2.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a cotton bud (b) white paper (c) yeast (d) a small bowl
3. 3.🧺 Do we need white paper for the secret lemon message? (a) not needed (b) needed
4. 4.🧺 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) a cotton bud (d) turmeric powder
5. 5.🧺 Which of these is not needed for the secret lemon message? (a) turmeric powder (b) a small bowl (c) lemon juice (d) an adult with an iron
6. 6.🍋 Which of these steps is a job a child can do? (a) ironing the paper (b) putting the iron away (c) reading the message (d) plugging in the iron
7. 7.🍋 Which of these steps is a job a child can do? (a) plugging in the iron (b) cutting the lemon (c) dipping the cotton bud (d) ironing the paper
8. 8.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is kept the same? (a) the ironing time (b) how dark the writing is (c) the kind of juice
9. 9.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the kind of juice”? (a) we keep it the same (b) we measure it (c) we change it
10. 10.🧺 Do we need a mirror for the secret lemon message? (a) not needed (b) needed
11. 11.True or false: a balloon is needed for the secret lemon message. (a) True (b) False
12. 12.🔮 Predict: you write with plain water instead of lemon juice. What appears after ironing? (a) almost nothing (b) blue words (c) a rainbow (d) dark brown words
13. 13.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) white paper (b) a cotton bud (c) lemon juice (d) a magnet
14. 14.⚖️ 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 change it (c) we keep it the same
15. 15.🧺 Do we need a small bowl for the secret lemon message? (a) needed (b) not needed
16. 16.⚖️ 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) the same cotton bud (c) how dark the writing is
17. 17.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the same paper is kept the same. (a) False (b) True
18. 18.🍋 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
19. 19.True or false: dipping the cotton bud is a job for an adult. (a) False (b) True
20. 20.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the same cotton bud”? (a) we measure it (b) we change it (c) we keep it the same
21. 21.🧺 Which of these is needed for the secret lemon message? (a) a mirror (b) yeast (c) turmeric powder (d) white paper
22. 22.⚖️ 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
23. 23.🔮 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
24. 24.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is what we measure? (a) the ironing time (b) how dark the writing is (c) the same cotton bud (d) the same paper
25. 25.True or false: a small bowl is needed for the secret lemon message. (a) False (b) True
26. 26.⚖️ 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 keep it the same (c) we change it
27. 27.🧺 Which of these is not needed for the secret lemon message? (a) an adult with an iron (b) white paper (c) a small bowl (d) yeast
28. 28.🍋 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) putting the iron away
29. 29.True or false: an adult with an iron is not needed for the secret lemon message. (a) True (b) False
30. 30.🍋 What colour does the lemon writing turn when an adult warms it? (a) green (b) white (c) blue (d) brown
31. 31.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) rub your eyes (b) wash your hands (c) skip washing (d) lick your fingers
32. 32.🧺 Which of these is not needed for the secret lemon message? (a) a balloon (b) a cotton bud (c) lemon juice (d) a small bowl
33. 33.⚖️ 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) the same paper (c) how dark the writing is
34. 34.🧺 Do we need a battery cell for the secret lemon message? (a) needed (b) not needed
35. 35.🧺 Do we need lemon juice for the secret lemon message? (a) needed (b) not needed
36. 36.🍋 Secret message: who does this step — writing the message? (a) an adult does it (b) a child can do it
37. 37.🍋 Secret message: who does this step — dipping the cotton bud? (a) an adult does it (b) a child can do it
38. 38.🧺 Do we need turmeric powder for the secret lemon message? (a) needed (b) not needed
39. 39.🍋 Which of these steps is a job a child can do? (a) putting the iron away (b) plugging in the iron (c) cutting the lemon (d) letting the paper dry
40. 40.🍋 Secret message: who does this step — letting the paper dry? (a) a child can do it (b) an adult does it

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