Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 407 · 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.🔍 Which is the odd one out? (a) ironing the paper (b) dipping the cotton bud (c) cutting the lemon (d) plugging in the iron
2. 2.🧺 Do we need turmeric powder for the secret lemon message? (a) needed (b) not needed
3. 3.🍋 Why can’t you see the lemon writing once it dries? (a) dry juice is see-through (b) the ink is magnetic (c) it turned into air (d) the paper ate it
4. 4.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the same paper”? (a) we change it (b) we measure it (c) we keep it the same
5. 5.📘 The browning of lemon juice with heat is a ___ change. (a) magnetic (b) musical (c) physical (d) chemical
6. 6.🧺 Do we need a mirror for the secret lemon message? (a) needed (b) not needed
7. 7.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is what we measure? (a) the kind of juice (b) the ironing time (c) the same paper (d) how dark the writing is
8. 8.🍋 Why does the lemon writing turn brown with heat? (a) the iron is brown (b) heat adds colour (c) the juice scorches first (d) paper turns lemony
9. 9.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) lemon juice (b) turmeric powder (c) a small bowl (d) a cotton bud
10. 10.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the same cotton bud is what we measure. (a) True (b) False
11. 11.⚖️ 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
12. 12.⚖️ 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 ironing time (c) how dark the writing is
13. 13.🍋 What colour does the lemon writing turn when an adult warms it? (a) brown (b) blue (c) green (d) white
14. 14.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) rub your eyes (b) skip washing (c) lick your fingers (d) wash your hands
15. 15.🧺 Do we need a battery cell for the secret lemon message? (a) not needed (b) needed
16. 16.True or false: cutting the lemon is a job for an adult. (a) False (b) True
17. 17.True or false: reading the message is a job a child can do. (a) True (b) False
18. 18.🧺 Which of these is needed for the secret lemon message? (a) turmeric powder (b) a balloon (c) lemon juice (d) yeast
19. 19.🧺 Which of these is needed for the secret lemon message? (a) a balloon (b) an adult with an iron (c) turmeric powder (d) a magnet
20. 20.🍋 Which of these steps is a job for an adult? (a) dipping the cotton bud (b) putting the iron away (c) writing the message (d) letting the paper dry
21. 21.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a mirror (b) an adult with an iron (c) a small bowl (d) white paper
22. 22.🛟 Why must children keep their fingers away from the iron? (a) it is magnetic (b) it can burn skin (c) it is sticky (d) it is cold
23. 23.🧺 Do we need an adult with an iron for the secret lemon message? (a) not needed (b) needed
24. 24.🍋 Which of these steps is a job a child can do? (a) writing the message (b) cutting the lemon (c) plugging in the iron (d) ironing the paper
25. 25.True or false: a magnet is needed for the secret lemon message. (a) True (b) False
26. 26.True or false: a battery cell is not needed for the secret lemon message. (a) False (b) True
27. 27.⚖️ 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) True (b) False
28. 28.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is the one thing we change? (a) the iron setting (b) the kind of juice (c) how dark the writing is (d) the ironing time
29. 29.🔍 Which is the odd one out? (a) letting the paper dry (b) cutting the lemon (c) writing the message (d) reading the message
30. 30.🔮 Predict: you write with plain water instead of lemon juice. What appears after ironing? (a) almost nothing (b) dark brown words (c) blue words (d) a rainbow
31. 31.🧺 Do we need a small bowl for the secret lemon message? (a) needed (b) not needed
32. 32.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the same cotton bud is kept the same. (a) False (b) True
33. 33.🧺 Do we need yeast for the secret lemon message? (a) needed (b) not needed
34. 34.🧺 Do we need a balloon for the secret lemon message? (a) needed (b) not needed
35. 35.🍋 Which of these steps is a job for an adult? (a) dipping the cotton bud (b) plugging in the iron (c) writing the message (d) reading the message
36. 36.True or false: a mirror is 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 change it (b) we measure it (c) we keep it the same
38. 38.🧺 Which of these is not needed for the secret lemon message? (a) a small bowl (b) a cotton bud (c) lemon juice (d) a battery cell
39. 39.True or false: turmeric powder is needed for the secret lemon message. (a) False (b) True
40. 40.True or false: turmeric powder is not needed for the secret lemon message. (a) False (b) True

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