Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 607 · 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: reading the message is a job a child can do. (a) True (b) False
2. 2.True or false: a cotton bud is needed for the secret lemon message. (a) True (b) False
3. 3.🧺 Which of these is not needed for the secret lemon message? (a) an adult with an iron (b) a battery cell (c) lemon juice (d) white paper
4. 4.🛟 Why must children keep their fingers away from the iron? (a) it is cold (b) it can burn skin (c) it is sticky (d) it is magnetic
5. 5.🧺 Do we need a small bowl for the secret lemon message? (a) not needed (b) needed
6. 6.🧺 Do we need an adult with an iron for the secret lemon message? (a) needed (b) not needed
7. 7.🔍 Which is the odd one out? (a) ironing the paper (b) cutting the lemon (c) writing the message (d) plugging in the iron
8. 8.🛟 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
9. 9.⚖️ 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
10. 10.🍋 Secret message: who does this step — dipping the cotton bud? (a) an adult does it (b) a child can do it
11. 11.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the kind of juice is kept the same. (a) False (b) True
12. 12.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) an adult with an iron (b) white paper (c) a battery cell (d) a cotton bud
13. 13.⚖️ 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
14. 14.True or false: a magnet is needed for the secret lemon message. (a) True (b) False
15. 15.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is what we measure? (a) the same cotton bud (b) the ironing time (c) the same paper (d) how dark the writing is
16. 16.🍋 Which of these steps is a job a child can do? (a) plugging in the iron (b) putting the iron away (c) cutting the lemon (d) reading the message
17. 17.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a small bowl (b) white paper (c) a magnet (d) lemon juice
18. 18.🔍 Which is the odd one out? (a) ironing the paper (b) writing the message (c) reading the message (d) dipping the cotton bud
19. 19.🍋 Which of these steps is a job for an adult? (a) writing the message (b) dipping the cotton bud (c) cutting the lemon (d) reading the message
20. 20.🍋 Secret message: who does this step — putting the iron away? (a) a child can do it (b) an adult does it
21. 21.True or false: letting the paper dry is a job for an adult. (a) True (b) False
22. 22.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is the one thing we change? (a) the kind of juice (b) the iron setting (c) the ironing time (d) the same cotton bud
23. 23.🧺 Do we need a magnet for the secret lemon message? (a) needed (b) not needed
24. 24.🛟 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
25. 25.🍋 Secret message: who does this step — writing the message? (a) a child can do it (b) an adult does it
26. 26.🔍 Which is the odd one out? (a) ironing the paper (b) cutting the lemon (c) putting the iron away (d) letting the paper dry
27. 27.🔮 Predict: the adult irons for only one second. What happens? (a) writing stays faint (b) writing turns green (c) it gets darker (d) the paper floats
28. 28.🧺 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) turmeric powder
29. 29.True or false: a mirror is needed for the secret lemon message. (a) True (b) False
30. 30.🍋 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) ironing the paper
31. 31.🧺 Do we need a cotton bud for the secret lemon message? (a) not needed (b) needed
32. 32.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “how dark the writing is”? (a) we change it (b) we keep it the same (c) we measure it
33. 33.True or false: an adult with an iron is not needed for the secret lemon message. (a) True (b) False
34. 34.True or false: lemon juice is not needed for the secret lemon message. (a) True (b) False
35. 35.⚖️ 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 paper
36. 36.⚖️ 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 ironing time (c) the kind of juice
37. 37.🧺 Which of these is not needed for the secret lemon message? (a) a balloon (b) white paper (c) a cotton bud (d) lemon juice
38. 38.🔍 Which is the odd one out? (a) plugging in the iron (b) cutting the lemon (c) ironing the paper (d) dipping the cotton bud
39. 39.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a cotton bud (b) an adult with an iron (c) a mirror (d) white paper
40. 40.⚖️ 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 keep it the same (c) we change it

Free science experiments lessons, practice and worksheets at talentjr.in/science-experiments-for-kids