Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 262 · 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: letting the paper dry is a job a child can do. (a) True (b) False
2. 2.True or false: a balloon is not needed for the secret lemon message. (a) True (b) False
3. 3.🍋 Which of these steps is a job a child can do? (a) putting the iron away (b) ironing the paper (c) plugging in the iron (d) reading the message
4. 4.🍋 What colour does the lemon writing turn when an adult warms it? (a) green (b) blue (c) white (d) brown
5. 5.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) yeast (b) white paper (c) lemon juice (d) an adult with an iron
6. 6.🍋 Secret message: who does this step — plugging in the iron? (a) an adult does it (b) a child can do it
7. 7.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a small bowl (b) white paper (c) turmeric powder (d) lemon juice
8. 8.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the iron setting is kept the same. (a) True (b) False
9. 9.🧺 Which of these is not needed for the secret lemon message? (a) white paper (b) a balloon (c) a cotton bud (d) an adult with an iron
10. 10.True or false: ironing the paper is a job a child can do. (a) False (b) True
11. 11.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) lemon juice (b) a balloon (c) a small bowl (d) white paper
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.🍋 Which of these steps is a job a child can do? (a) ironing the paper (b) plugging in the iron (c) cutting the lemon (d) letting the paper dry
14. 14.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is what we measure? (a) the same paper (b) the same cotton bud (c) how dark the writing is (d) the ironing time
15. 15.🧺 Do we need yeast for the secret lemon message? (a) not needed (b) needed
16. 16.True or false: a cotton bud is needed for the secret lemon message. (a) False (b) True
17. 17.True or false: white paper is not needed for the secret lemon message. (a) True (b) False
18. 18.⚖️ 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 keep it the same (c) we change it
19. 19.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) white paper (b) lemon juice (c) a small bowl (d) a magnet
20. 20.🧺 Do we need a cotton bud for the secret lemon message? (a) needed (b) not needed
21. 21.🛟 Who should use the hot iron in the secret message experiment? (a) whoever is fastest (b) the youngest child (c) only an adult (d) any child
22. 22.🔍 Which is the odd one out? (a) putting the iron away (b) ironing the paper (c) cutting the lemon (d) reading the message
23. 23.True or false: white paper is needed for the secret lemon message. (a) False (b) True
24. 24.True or false: a small bowl is needed for the secret lemon message. (a) False (b) True
25. 25.True or false: plugging in the iron is a job a child can do. (a) True (b) False
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 change it (c) we keep it the same
27. 27.🔍 Which is the odd one out? (a) writing the message (b) letting the paper dry (c) plugging in the iron (d) reading the message
28. 28.🔍 Which is the odd one out? (a) dipping the cotton bud (b) reading the message (c) cutting the lemon (d) letting the paper dry
29. 29.🧺 Do we need a magnet for the secret lemon message? (a) not needed (b) needed
30. 30.True or false: writing the message is a job a child can do. (a) False (b) True
31. 31.🛟 Why must children keep their fingers away from the iron? (a) it can burn skin (b) it is magnetic (c) it is sticky (d) it is cold
32. 32.True or false: dipping the cotton bud is a job for an adult. (a) False (b) True
33. 33.🍋 Why can’t you see the lemon writing once it dries? (a) the ink is magnetic (b) dry juice is see-through (c) it turned into air (d) the paper ate it
34. 34.🔮 Predict: the adult irons for only one second. What happens? (a) it gets darker (b) writing turns green (c) the paper floats (d) writing stays faint
35. 35.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the kind of juice is the one thing we change. (a) False (b) True
36. 36.⚖️ 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
37. 37.True or false: putting the iron away is a job a child can do. (a) True (b) False
38. 38.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the same cotton bud is the one thing we change. (a) True (b) False
39. 39.🛟 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
40. 40.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the iron setting”? (a) we measure it (b) we change it (c) we keep it the same

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