Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 309 · 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.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) turmeric powder (b) white paper (c) an adult with an iron (d) a small bowl
2. 2.🛟 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
3. 3.True or false: a cotton bud is needed for the secret lemon message. (a) True (b) False
4. 4.🔍 Which is the odd one out? (a) writing the message (b) ironing the paper (c) dipping the cotton bud (d) reading the message
5. 5.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) white paper (b) a balloon (c) a small bowl (d) an adult with an iron
6. 6.True or false: putting the iron away is a job for an adult. (a) True (b) False
7. 7.True or false: a mirror is needed for the secret lemon message. (a) False (b) True
8. 8.🍋 Why does the lemon writing turn brown with heat? (a) paper turns lemony (b) heat adds colour (c) the juice scorches first (d) the iron is brown
9. 9.True or false: plugging in the iron is a job a child can do. (a) False (b) True
10. 10.True or false: letting the paper dry is a job for an adult. (a) True (b) False
11. 11.True or false: white paper is needed for the secret lemon message. (a) False (b) True
12. 12.🍋 Why can’t you see the lemon writing once it dries? (a) the paper ate it (b) the ink is magnetic (c) it turned into air (d) dry juice is see-through
13. 13.🔮 Predict: you write with plain water instead of lemon juice. What appears after ironing? (a) dark brown words (b) blue words (c) almost nothing (d) a rainbow
14. 14.🧺 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) a magnet
15. 15.🧺 Which of these is needed for the secret lemon message? (a) a battery cell (b) a balloon (c) a magnet (d) white paper
16. 16.🍋 Secret message: who does this step — cutting the lemon? (a) an adult does it (b) a child can do it
17. 17.⚖️ 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 keep it the same (c) we measure it
18. 18.🔍 Which is the odd one out? (a) cutting the lemon (b) plugging in the iron (c) ironing the paper (d) letting the paper dry
19. 19.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is kept the same? (a) the same cotton bud (b) how dark the writing is (c) the kind of juice
20. 20.🧺 Which of these is needed for the secret lemon message? (a) a battery cell (b) a magnet (c) yeast (d) an adult with an iron
21. 21.⚖️ 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 kind of juice (c) the same paper (d) the same cotton bud
22. 22.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a cotton bud (b) a small bowl (c) lemon juice (d) a mirror
23. 23.🧺 Which of these is needed for the secret lemon message? (a) a battery cell (b) a balloon (c) a small bowl (d) turmeric powder
24. 24.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: how dark the writing is is what we measure. (a) False (b) True
25. 25.🛟 Who should use the hot iron in the secret message experiment? (a) only an adult (b) any child (c) the youngest child (d) whoever is fastest
26. 26.🍋 Which of these steps is a job for an adult? (a) letting the paper dry (b) dipping the cotton bud (c) writing the message (d) ironing the paper
27. 27.True or false: dipping the cotton bud is a job for an adult. (a) False (b) True
28. 28.🍋 Secret message: who does this step — plugging in the iron? (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) an adult with an iron (b) lemon juice (c) a battery cell (d) a cotton bud
30. 30.⚖️ 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
31. 31.⚖️ 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) False (b) True
32. 32.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the iron setting is kept the same. (a) False (b) True
33. 33.⚖️ 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 kind of juice (c) the same paper
34. 34.📘 The browning of lemon juice with heat is a ___ change. (a) magnetic (b) physical (c) musical (d) chemical
35. 35.True or false: a cotton bud is not needed for the secret lemon message. (a) True (b) False
36. 36.🍋 Which of these steps is a job a child can do? (a) cutting the lemon (b) letting the paper dry (c) putting the iron away (d) ironing the paper
37. 37.🧺 Do we need turmeric powder for the secret lemon message? (a) not needed (b) needed
38. 38.🧺 Do we need a magnet for the secret lemon message? (a) needed (b) not needed
39. 39.🍋 Which of these steps is a job for an adult? (a) writing the message (b) letting the paper dry (c) dipping the cotton bud (d) plugging in the iron
40. 40.🧺 Do we need lemon juice for the secret lemon message? (a) needed (b) not needed

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