Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 863 · 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: plugging in the iron is a job a child can do. (a) True (b) False
2. 2.🔍 Which is the odd one out? (a) reading the message (b) letting the paper dry (c) putting the iron away (d) dipping the cotton bud
3. 3.⚖️ 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 same paper (c) the kind of juice
4. 4.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the same paper is what we measure. (a) False (b) True
5. 5.🍋 Secret message: who does this step — ironing the paper? (a) a child can do it (b) an adult does it
6. 6.🧺 Which of these is needed for the secret lemon message? (a) an adult with an iron (b) a balloon (c) a magnet (d) a battery cell
7. 7.🛟 Why must children keep their fingers away from the iron? (a) it is magnetic (b) it can burn skin (c) it is cold (d) it is sticky
8. 8.🧺 Which of these is needed for the secret lemon message? (a) yeast (b) a cotton bud (c) a magnet (d) a battery cell
9. 9.True or false: reading the message is a job a child can do. (a) False (b) True
10. 10.⚖️ 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 measure it (c) we change it
11. 11.🧺 Do we need white paper for the secret lemon message? (a) not needed (b) needed
12. 12.🧺 Do we need a small bowl for the secret lemon message? (a) needed (b) not needed
13. 13.⚖️ 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 ironing time (c) the iron setting (d) the kind of juice
14. 14.🧺 Do we need an adult with an iron for the secret lemon message? (a) needed (b) not needed
15. 15.🧺 Which of these is not needed for the secret lemon message? (a) an adult with an iron (b) white paper (c) lemon juice (d) turmeric powder
16. 16.🛟 Who should use the hot iron in the secret message experiment? (a) the youngest child (b) only an adult (c) any child (d) whoever is fastest
17. 17.True or false: turmeric powder is needed for the secret lemon message. (a) True (b) False
18. 18.🧺 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) turmeric powder
19. 19.🧺 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 cotton bud (d) yeast
20. 20.📘 The browning of lemon juice with heat is a ___ change. (a) chemical (b) magnetic (c) physical (d) musical
21. 21.🍋 Why can’t you see the lemon writing once it dries? (a) the paper ate it (b) the ink is magnetic (c) dry juice is see-through (d) it turned into air
22. 22.🍋 Secret message: who does this step — dipping the cotton bud? (a) a child can do it (b) an adult does it
23. 23.🍋 Why does the lemon writing turn brown with heat? (a) heat adds colour (b) the iron is brown (c) the juice scorches first (d) paper turns lemony
24. 24.⚖️ 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
25. 25.🍋 Secret message: who does this step — cutting the lemon? (a) an adult does it (b) a child can do it
26. 26.True or false: yeast is needed for the secret lemon message. (a) False (b) True
27. 27.True or false: yeast is not needed for the secret lemon message. (a) False (b) True
28. 28.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is kept the same? (a) the ironing time (b) how dark the writing is (c) the kind of juice
29. 29.⚖️ 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
30. 30.🍋 Which of these steps is a job for an adult? (a) putting the iron away (b) writing the message (c) dipping the cotton bud (d) reading the message
31. 31.True or false: a mirror is needed for the secret lemon message. (a) False (b) True
32. 32.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a cotton bud (b) a balloon (c) white paper (d) lemon juice
33. 33.True or false: plugging in the iron is a job for an adult. (a) True (b) False
34. 34.🔍 Which is the odd one out? (a) ironing the paper (b) dipping the cotton bud (c) plugging in the iron (d) cutting the lemon
35. 35.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is what we measure? (a) the ironing time (b) the iron setting (c) how dark the writing is (d) the same cotton bud
36. 36.🍋 Which of these steps is a job a child can do? (a) ironing the paper (b) letting the paper dry (c) plugging in the iron (d) putting the iron away
37. 37.🔍 Which is the odd one out? (a) cutting the lemon (b) ironing the paper (c) reading the message (d) plugging in the iron
38. 38.🔮 Predict: the adult irons for only one second. What happens? (a) writing turns green (b) it gets darker (c) the paper floats (d) writing stays faint
39. 39.🍋 Which of these steps is a job a child can do? (a) reading the message (b) ironing the paper (c) cutting the lemon (d) plugging in the iron
40. 40.🔍 Which is the odd one out? (a) cutting the lemon (b) plugging in the iron (c) ironing the paper (d) writing the message

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