Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 744 · 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 — writing the message? (a) an adult does it (b) a child can do it
2. 2.🛟 Who should use the hot iron in the secret message experiment? (a) only an adult (b) whoever is fastest (c) any child (d) the youngest child
3. 3.🧺 Which of these is needed for the secret lemon message? (a) lemon juice (b) a balloon (c) turmeric powder (d) a magnet
4. 4.🔍 Which is the odd one out? (a) cutting the lemon (b) dipping the cotton bud (c) reading the message (d) writing the message
5. 5.⚖️ 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
6. 6.🍋 Which of these steps is a job a child can do? (a) ironing the paper (b) putting the iron away (c) plugging in the iron (d) writing the message
7. 7.True or false: white paper is needed for the secret lemon message. (a) True (b) False
8. 8.🧺 Do we need a cotton bud for the secret lemon message? (a) needed (b) not needed
9. 9.🧺 Which of these is not needed for the secret lemon message? (a) lemon juice (b) a cotton bud (c) a balloon (d) white paper
10. 10.True or false: a magnet is needed for the secret lemon message. (a) False (b) True
11. 11.🧺 Do we need turmeric powder for the secret lemon message? (a) needed (b) not needed
12. 12.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) an adult with an iron (b) turmeric powder (c) white paper (d) a small bowl
13. 13.True or false: reading the message is a job for an adult. (a) True (b) False
14. 14.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is the one thing we change? (a) the same cotton bud (b) the kind of juice (c) the iron setting (d) the same paper
15. 15.🔍 Which is the odd one out? (a) plugging in the iron (b) dipping the cotton bud (c) putting the iron away (d) cutting the lemon
16. 16.🔍 Which is the odd one out? (a) letting the paper dry (b) writing the message (c) ironing the paper (d) reading the message
17. 17.True or false: letting the paper dry is a job for an adult. (a) True (b) False
18. 18.🍋 Which of these steps is a job a child can do? (a) plugging in the iron (b) cutting the lemon (c) reading the message (d) putting the iron away
19. 19.🍋 Which of these steps is a job for an adult? (a) dipping the cotton bud (b) putting the iron away (c) letting the paper dry (d) writing the message
20. 20.🧺 Which of these is not needed for the secret lemon message? (a) white paper (b) a cotton bud (c) lemon juice (d) a mirror
21. 21.⚖️ 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) True (b) False
22. 22.🍋 Secret message: who does this step — ironing the paper? (a) a child can do it (b) an adult does it
23. 23.⚖️ 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
24. 24.🍋 Secret message: who does this step — dipping the cotton bud? (a) a child can do it (b) an adult does it
25. 25.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) lick your fingers (b) skip washing (c) wash your hands (d) rub your eyes
26. 26.🧺 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 mirror
27. 27.🧺 Which of these is not needed for the secret lemon message? (a) a small bowl (b) turmeric powder (c) lemon juice (d) a cotton bud
28. 28.🍋 Secret message: who does this step — reading the message? (a) a child can do it (b) an adult does it
29. 29.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) white paper (b) a balloon (c) lemon juice (d) an adult with an iron
30. 30.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: how dark the writing is is kept the same. (a) True (b) False
31. 31.🧺 Do we need yeast for the secret lemon message? (a) needed (b) not needed
32. 32.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the iron setting”? (a) we change it (b) we measure it (c) we keep it the same
33. 33.🔮 Predict: the adult irons for only one second. What happens? (a) the paper floats (b) it gets darker (c) writing stays faint (d) writing turns green
34. 34.🧺 Which of these is needed for the secret lemon message? (a) a battery cell (b) a cotton bud (c) a magnet (d) yeast
35. 35.🔮 Can the brown writing go back to being invisible? (a) yes, if shaken (b) yes, if cooled (c) no, it stays brown (d) yes, in the dark
36. 36.🛟 Why must children keep their fingers away from the iron? (a) it is sticky (b) it is cold (c) it is magnetic (d) it can burn skin
37. 37.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) white paper (b) an adult with an iron (c) a cotton bud (d) yeast
38. 38.⚖️ 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
39. 39.🍋 Secret message: who does this step — plugging in the iron? (a) an adult does it (b) a child can do it
40. 40.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the kind of juice is what we measure. (a) False (b) True

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