Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 268 · 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.🍋 Secret message: who does this step — dipping the cotton bud? (a) an adult does it (b) a child can do it
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) a cotton bud (b) a magnet (c) lemon juice (d) white paper
4. 4.🛟 Why must children keep their fingers away from the iron? (a) it is sticky (b) it is cold (c) it can burn skin (d) it is magnetic
5. 5.🧺 Do we need a battery cell for the secret lemon message? (a) not needed (b) needed
6. 6.🔍 Which is the odd one out? (a) dipping the cotton bud (b) writing the message (c) letting the paper dry (d) putting the iron away
7. 7.True or false: cutting the lemon is a job for an adult. (a) True (b) False
8. 8.🔍 Which is the odd one out? (a) letting the paper dry (b) plugging in the iron (c) writing the message (d) reading the message
9. 9.True or false: ironing the paper is a job for an adult. (a) True (b) False
10. 10.🍋 Which of these steps is a job for an adult? (a) dipping the cotton bud (b) putting the iron away (c) reading the message (d) writing the message
11. 11.🧺 Do we need a magnet for the secret lemon message? (a) needed (b) not needed
12. 12.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: how dark the writing is is the one thing we change. (a) True (b) False
13. 13.🛟 Who should use the hot iron in the secret message experiment? (a) any child (b) whoever is fastest (c) only an adult (d) the youngest child
14. 14.🍋 Which of these steps is a job a child can do? (a) cutting the lemon (b) ironing the paper (c) putting the iron away (d) reading the message
15. 15.🍋 Why can’t you see the lemon writing once it dries? (a) it turned into air (b) the ink is magnetic (c) dry juice is see-through (d) the paper ate it
16. 16.True or false: a cotton bud is not needed for the secret lemon message. (a) True (b) False
17. 17.🧺 Which of these is needed for the secret lemon message? (a) a balloon (b) a small bowl (c) turmeric powder (d) a battery cell
18. 18.🧺 Do we need an adult with an iron for the secret lemon message? (a) not needed (b) needed
19. 19.⚖️ 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) how dark the writing is (c) the same cotton bud
20. 20.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the same cotton bud is what we measure. (a) False (b) True
21. 21.🔮 Predict: the adult irons for only one second. What happens? (a) writing turns green (b) writing stays faint (c) it gets darker (d) the paper floats
22. 22.🍋 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
23. 23.🧺 Do we need a mirror for the secret lemon message? (a) needed (b) not needed
24. 24.True or false: dipping the cotton bud is a job for an adult. (a) False (b) True
25. 25.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) white paper (b) a cotton bud (c) yeast (d) an adult with an iron
26. 26.🧺 Which of these is not needed for the secret lemon message? (a) white paper (b) a small bowl (c) an adult with an iron (d) a mirror
27. 27.🍋 What colour does the lemon writing turn when an adult warms it? (a) green (b) brown (c) blue (d) white
28. 28.🧺 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) an adult with an iron
29. 29.⚖️ 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 change it (c) we measure it
30. 30.🧺 Which of these is needed for the secret lemon message? (a) a mirror (b) lemon juice (c) a magnet (d) turmeric powder
31. 31.True or false: lemon juice is needed for the secret lemon message. (a) False (b) True
32. 32.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the same cotton bud is kept the same. (a) False (b) True
33. 33.🧺 Which of these is not needed for the secret lemon message? (a) a magnet (b) white paper (c) lemon juice (d) an adult with an iron
34. 34.🔍 Which is the odd one out? (a) putting the iron away (b) ironing the paper (c) reading the message (d) cutting the lemon
35. 35.⚖️ 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 same paper (c) the same cotton bud (d) how dark the writing is
36. 36.True or false: an adult with an iron is not needed for the secret lemon message. (a) True (b) False
37. 37.⚖️ 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 iron setting
38. 38.⚖️ 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 kind of juice (c) the iron setting (d) the ironing time
39. 39.🍋 Which of these steps is a job for an adult? (a) dipping the cotton bud (b) reading the message (c) writing the message (d) ironing the paper
40. 40.⚖️ 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 measure it (c) we change it

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