Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 276 · 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) dipping the cotton bud (d) writing the message
2. 2.🔮 Predict: the adult irons for only one second. What happens? (a) writing turns green (b) it gets darker (c) the paper floats (d) writing stays faint
3. 3.🧺 Which of these is needed for the secret lemon message? (a) turmeric powder (b) a battery cell (c) a balloon (d) an adult with an iron
4. 4.🍋 Secret message: who does this step — ironing the paper? (a) a child can do it (b) an adult does it
5. 5.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) skip washing (b) lick your fingers (c) rub your eyes (d) wash your hands
6. 6.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) white paper (b) a battery cell (c) an adult with an iron (d) lemon juice
7. 7.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) lemon juice (b) a cotton bud (c) a mirror (d) a small bowl
8. 8.🍋 What colour does the lemon writing turn when an adult warms it? (a) blue (b) green (c) white (d) brown
9. 9.🧺 Do we need a small bowl for the secret lemon message? (a) needed (b) not needed
10. 10.True or false: writing the message is a job for an adult. (a) True (b) False
11. 11.🧺 Which of these is not needed for the secret lemon message? (a) yeast (b) lemon juice (c) white paper (d) a cotton bud
12. 12.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the ironing time is the one thing we change. (a) True (b) False
13. 13.🔍 Which is the odd one out? (a) putting the iron away (b) cutting the lemon (c) dipping the cotton bud (d) ironing the paper
14. 14.True or false: turmeric powder is not needed for the secret lemon message. (a) False (b) True
15. 15.⚖️ 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
16. 16.🍋 Why does the lemon writing turn brown with heat? (a) the juice scorches first (b) heat adds colour (c) the iron is brown (d) paper turns lemony
17. 17.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) an adult with an iron (b) yeast (c) a small bowl (d) white paper
18. 18.🍋 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) cutting the lemon
19. 19.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a balloon (b) an adult with an iron (c) white paper (d) a cotton bud
20. 20.🧺 Do we need turmeric powder for the secret lemon message? (a) needed (b) not needed
21. 21.🔍 Which is the odd one out? (a) ironing the paper (b) putting the iron away (c) letting the paper dry (d) plugging in the iron
22. 22.🧺 Which of these is needed for the secret lemon message? (a) a balloon (b) a magnet (c) a cotton bud (d) turmeric powder
23. 23.⚖️ 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
24. 24.True or false: letting the paper dry is a job for an adult. (a) True (b) False
25. 25.🔍 Which is the odd one out? (a) letting the paper dry (b) dipping the cotton bud (c) ironing the paper (d) reading the message
26. 26.⚖️ 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
27. 27.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the kind of juice is what we measure. (a) True (b) False
28. 28.🍋 Secret message: who does this step — plugging in the iron? (a) a child can do it (b) an adult does it
29. 29.🛟 Who should use the hot iron in the secret message experiment? (a) whoever is fastest (b) any child (c) the youngest child (d) only an adult
30. 30.True or false: an adult with an iron is not needed for the secret lemon message. (a) True (b) False
31. 31.⚖️ 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
32. 32.⚖️ 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
33. 33.True or false: writing the message is a job a child can do. (a) True (b) False
34. 34.🧺 Do we need a cotton bud for the secret lemon message? (a) not needed (b) needed
35. 35.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the same paper is the one thing we change. (a) True (b) False
36. 36.True or false: plugging in the iron is a job a child can do. (a) True (b) False
37. 37.🛟 Why must children keep their fingers away from the iron? (a) it is magnetic (b) it is sticky (c) it can burn skin (d) it is cold
38. 38.⚖️ 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
39. 39.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a cotton bud (b) turmeric powder (c) lemon juice (d) white paper
40. 40.⚖️ 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 same paper (c) how dark the writing is (d) the iron setting

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