Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 380 · 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: lemon juice is not needed for the secret lemon message. (a) True (b) False
2. 2.🔮 Can the brown writing go back to being invisible? (a) yes, in the dark (b) yes, if cooled (c) yes, if shaken (d) no, it stays brown
3. 3.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) wash your hands (b) rub your eyes (c) skip washing (d) lick your fingers
4. 4.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) yeast (b) lemon juice (c) white paper (d) a small bowl
5. 5.⚖️ 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
6. 6.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) an adult with an iron (b) a mirror (c) a small bowl (d) white paper
7. 7.True or false: cutting the lemon is a job a child can do. (a) True (b) False
8. 8.🍋 Which of these steps is a job for an adult? (a) reading the message (b) letting the paper dry (c) plugging in the iron (d) dipping the cotton bud
9. 9.⚖️ 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
10. 10.🧺 Do we need a mirror for the secret lemon message? (a) not needed (b) needed
11. 11.🍋 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
12. 12.True or false: plugging in the iron is a job for an adult. (a) True (b) False
13. 13.True or false: a cotton bud is not needed for the secret lemon message. (a) False (b) True
14. 14.🧺 Which of these is not needed for the secret lemon message? (a) a small bowl (b) a cotton bud (c) a balloon (d) lemon juice
15. 15.🍋 Which of these steps is a job a child can do? (a) plugging in the iron (b) dipping the cotton bud (c) cutting the lemon (d) ironing the paper
16. 16.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is the one thing we change? (a) the same paper (b) the same cotton bud (c) how dark the writing is (d) the kind of juice
17. 17.True or false: writing the message is a job for an adult. (a) True (b) False
18. 18.🔍 Which is the odd one out? (a) ironing the paper (b) plugging in the iron (c) putting the iron away (d) letting the paper dry
19. 19.🛟 Why must children keep their fingers away from the iron? (a) it is sticky (b) it can burn skin (c) it is cold (d) it is magnetic
20. 20.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) lemon juice (b) a cotton bud (c) white paper (d) a battery cell
21. 21.🧺 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) turmeric powder (d) a cotton bud
22. 22.🧺 Which of these is not needed for the secret lemon message? (a) a magnet (b) lemon juice (c) a cotton bud (d) white paper
23. 23.⚖️ 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 kind of juice
24. 24.⚖️ 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
25. 25.True or false: white paper is not needed for the secret lemon message. (a) True (b) False
26. 26.🍋 Which of these steps is a job for an adult? (a) writing the message (b) letting the paper dry (c) putting the iron away (d) dipping the cotton bud
27. 27.🍋 Which of these steps is a job for an adult? (a) dipping the cotton bud (b) ironing the paper (c) letting the paper dry (d) reading the message
28. 28.⚖️ 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
29. 29.⚖️ 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
30. 30.🍋 Which of these steps is a job a child can do? (a) putting the iron away (b) cutting the lemon (c) writing the message (d) plugging in the iron
31. 31.🔍 Which is the odd one out? (a) ironing the paper (b) plugging in the iron (c) cutting the lemon (d) dipping the cotton bud
32. 32.🔍 Which is the odd one out? (a) plugging in the iron (b) writing the message (c) reading the message (d) letting the paper dry
33. 33.🍋 Secret message: who does this step — ironing the paper? (a) an adult does it (b) a child can do it
34. 34.🧺 Do we need a small bowl for the secret lemon message? (a) needed (b) not needed
35. 35.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is kept the same? (a) the same paper (b) how dark the writing is (c) the kind of juice
36. 36.🧺 Do we need turmeric powder for the secret lemon message? (a) needed (b) not needed
37. 37.🍋 Secret message: who does this step — writing the message? (a) a child can do it (b) an adult does it
38. 38.True or false: plugging in the iron is a job a child can do. (a) True (b) False
39. 39.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the ironing time is what we measure. (a) True (b) False
40. 40.⚖️ 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

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