Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 269 · 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 — putting the iron away? (a) an adult does it (b) a child can do it
2. 2.🍋 Why does the lemon writing turn brown with heat? (a) paper turns lemony (b) the iron is brown (c) the juice scorches first (d) heat adds colour
3. 3.⚖️ 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 same paper (c) the same cotton bud (d) the ironing time
4. 4.🍋 Which of these steps is a job for an adult? (a) writing the message (b) cutting the lemon (c) letting the paper dry (d) reading the message
5. 5.🧺 Which of these is not needed for the secret lemon message? (a) a cotton bud (b) lemon juice (c) yeast (d) a small bowl
6. 6.🧺 Which of these is needed for the secret lemon message? (a) yeast (b) a battery cell (c) a small bowl (d) a magnet
7. 7.🧺 Do we need an adult with an iron for the secret lemon message? (a) needed (b) not needed
8. 8.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is what we measure? (a) how dark the writing is (b) the ironing time (c) the iron setting (d) the same paper
9. 9.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a cotton bud (b) lemon juice (c) white paper (d) a magnet
10. 10.⚖️ 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) the same paper (c) how dark the writing is
11. 11.True or false: a magnet is needed for the secret lemon message. (a) True (b) False
12. 12.🔮 Predict: you write with plain water instead of lemon juice. What appears after ironing? (a) dark brown words (b) almost nothing (c) a rainbow (d) blue words
13. 13.True or false: a balloon is needed for the secret lemon message. (a) True (b) False
14. 14.True or false: cutting the lemon is a job a child can do. (a) True (b) False
15. 15.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) an adult with an iron (b) a small bowl (c) lemon juice (d) a balloon
16. 16.⚖️ 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
17. 17.🍋 Secret message: who does this step — ironing the paper? (a) an adult does it (b) a child can do it
18. 18.🛟 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
19. 19.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) lick your fingers (b) wash your hands (c) rub your eyes (d) skip washing
20. 20.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a small bowl (b) a cotton bud (c) white paper (d) turmeric powder
21. 21.🧺 Do we need a balloon for the secret lemon message? (a) needed (b) not needed
22. 22.🍋 Which of these steps is a job for an adult? (a) writing the message (b) ironing the paper (c) letting the paper dry (d) reading the message
23. 23.True or false: a small bowl is not needed for the secret lemon message. (a) False (b) True
24. 24.🍋 Which of these steps is a job for an adult? (a) letting the paper dry (b) writing the message (c) reading the message (d) putting the iron away
25. 25.True or false: a cotton bud is needed for the secret lemon message. (a) False (b) True
26. 26.🧺 Do we need a mirror for the secret lemon message? (a) not needed (b) needed
27. 27.🍋 Which of these steps is a job a child can do? (a) cutting the lemon (b) reading the message (c) ironing the paper (d) plugging in the iron
28. 28.🍋 Secret message: who does this step — dipping the cotton bud? (a) an adult does it (b) a child can do it
29. 29.True or false: ironing the paper is a job a child can do. (a) False (b) True
30. 30.🍋 Secret message: who does this step — plugging in the iron? (a) an adult does it (b) a child can do it
31. 31.🧺 Do we need a battery cell for the secret lemon message? (a) needed (b) not needed
32. 32.True or false: reading the message is a job a child can do. (a) False (b) True
33. 33.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the same paper is the one thing we change. (a) True (b) False
34. 34.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the same cotton bud”? (a) we keep it the same (b) we change it (c) we measure it
35. 35.True or false: turmeric powder is not needed for the secret lemon message. (a) True (b) False
36. 36.True or false: a cotton bud is not needed for the secret lemon message. (a) False (b) True
37. 37.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the ironing time”? (a) we measure it (b) we change it (c) we keep it the same
38. 38.🧺 Do we need a magnet for the secret lemon message? (a) needed (b) not needed
39. 39.True or false: a mirror is not needed for the secret lemon message. (a) True (b) False
40. 40.🧺 Do we need turmeric powder for the secret lemon message? (a) not needed (b) needed

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