Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 838 · 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.True or false: turmeric powder is not needed for the secret lemon message. (a) False (b) True
2. 2.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is kept the same? (a) how dark the writing is (b) the kind of juice (c) the ironing time
3. 3.⚖️ 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) how dark the writing is (d) the kind of juice
4. 4.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a small bowl (b) white paper (c) lemon juice (d) a magnet
5. 5.⚖️ 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) True (b) False
6. 6.🧺 Do we need a magnet for the secret lemon message? (a) needed (b) not needed
7. 7.🔍 Which is the odd one out? (a) letting the paper dry (b) cutting the lemon (c) ironing the paper (d) plugging in the iron
8. 8.🧺 Which of these is needed for the secret lemon message? (a) a cotton bud (b) a magnet (c) yeast (d) turmeric powder
9. 9.🛟 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
10. 10.🧺 Do we need yeast for the secret lemon message? (a) not needed (b) needed
11. 11.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a small bowl (b) lemon juice (c) white paper (d) a battery cell
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.🧺 Which of these is not needed for the secret lemon message? (a) white paper (b) lemon juice (c) a small bowl (d) a balloon
14. 14.True or false: lemon juice is not needed for the secret lemon message. (a) True (b) False
15. 15.🔮 Predict: you write with plain water instead of lemon juice. What appears after ironing? (a) dark brown words (b) a rainbow (c) almost nothing (d) blue words
16. 16.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the iron setting is what we measure. (a) True (b) False
17. 17.🍋 Secret message: who does this step — letting the paper dry? (a) an adult does it (b) a child can do it
18. 18.⚖️ 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
19. 19.🔍 Which is the odd one out? (a) putting the iron away (b) plugging in the iron (c) dipping the cotton bud (d) ironing the paper
20. 20.🍋 Secret message: who does this step — cutting the lemon? (a) an adult does it (b) a child can do it
21. 21.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) an adult with an iron (b) a balloon (c) lemon juice (d) a small bowl
22. 22.🧺 Which of these is not needed for the secret lemon message? (a) a cotton bud (b) an adult with an iron (c) turmeric powder (d) a small bowl
23. 23.🍋 Which of these steps is a job a child can do? (a) putting the iron away (b) writing the message (c) plugging in the iron (d) ironing the paper
24. 24.⚖️ 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 change it (c) we measure it
25. 25.🍋 Secret message: who does this step — putting the iron away? (a) an adult does it (b) a child can do it
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 ironing time (d) the kind of juice
27. 27.🧺 Do we need a cotton bud for the secret lemon message? (a) not needed (b) needed
28. 28.True or false: white paper is needed for the secret lemon message. (a) False (b) True
29. 29.True or false: dipping the cotton bud is a job a child can do. (a) False (b) True
30. 30.🍋 Which of these steps is a job a child can do? (a) cutting the lemon (b) plugging in the iron (c) ironing the paper (d) dipping the cotton bud
31. 31.🧺 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) turmeric powder (d) a cotton bud
32. 32.🍋 Which of these steps is a job a child can do? (a) cutting the lemon (b) putting the iron away (c) ironing the paper (d) letting the paper dry
33. 33.🍋 Why can’t you see the lemon writing once it dries? (a) dry juice is see-through (b) it turned into air (c) the ink is magnetic (d) the paper ate it
34. 34.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a small bowl (b) yeast (c) a cotton bud (d) lemon juice
35. 35.🍋 Which of these steps is a job for an adult? (a) letting the paper dry (b) writing the message (c) ironing the paper (d) reading the message
36. 36.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the ironing time”? (a) we change it (b) we measure it (c) we keep it the same
37. 37.⚖️ 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
38. 38.🛟 Who should use the hot iron in the secret message experiment? (a) the youngest child (b) any child (c) only an adult (d) whoever is fastest
39. 39.🧺 Which of these is not needed for the secret lemon message? (a) a small bowl (b) white paper (c) a battery cell (d) a cotton bud
40. 40.📘 The browning of lemon juice with heat is a ___ change. (a) chemical (b) magnetic (c) musical (d) physical

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