Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 968 · 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: a mirror is not needed for the secret lemon message. (a) False (b) True
2. 2.🔍 Which is the odd one out? (a) reading the message (b) putting the iron away (c) cutting the lemon (d) plugging in the iron
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 same paper (b) the kind of juice (c) the iron setting (d) how dark the writing is
4. 4.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the kind of juice is what we measure. (a) True (b) False
5. 5.True or false: a balloon is needed for the secret lemon message. (a) True (b) False
6. 6.🍋 Secret message: who does this step — dipping the cotton bud? (a) a child can do it (b) an adult does it
7. 7.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a balloon (b) a small bowl (c) white paper (d) a cotton bud
8. 8.🍋 Secret message: who does this step — cutting the lemon? (a) an adult does it (b) a child can do it
9. 9.⚖️ 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 iron setting (c) the same paper (d) how dark the writing is
10. 10.🔍 Which is the odd one out? (a) ironing the paper (b) dipping the cotton bud (c) writing the message (d) reading the message
11. 11.🧺 Do we need a balloon for the secret lemon message? (a) not needed (b) needed
12. 12.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) lick your fingers (b) rub your eyes (c) wash your hands (d) skip washing
13. 13.True or false: a cotton bud is needed for the secret lemon message. (a) True (b) False
14. 14.True or false: reading the message is a job a child can do. (a) True (b) False
15. 15.🍋 What colour does the lemon writing turn when an adult warms it? (a) green (b) blue (c) brown (d) white
16. 16.🛟 Why must children keep their fingers away from the iron? (a) it is sticky (b) it is magnetic (c) it is cold (d) it can burn skin
17. 17.🔍 Which is the odd one out? (a) dipping the cotton bud (b) putting the iron away (c) cutting the lemon (d) plugging in the iron
18. 18.🔮 Can the brown writing go back to being invisible? (a) yes, in the dark (b) no, it stays brown (c) yes, if cooled (d) yes, if shaken
19. 19.🧺 Which of these is needed for the secret lemon message? (a) a magnet (b) white paper (c) turmeric powder (d) a balloon
20. 20.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a cotton bud (b) lemon juice (c) a battery cell (d) a small bowl
21. 21.🧺 Which of these is not needed for the secret lemon message? (a) white paper (b) a small bowl (c) a balloon (d) a cotton bud
22. 22.🍋 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
23. 23.True or false: dipping the cotton bud is a job a child can do. (a) False (b) True
24. 24.🔍 Which is the odd one out? (a) cutting the lemon (b) putting the iron away (c) plugging in the iron (d) writing the message
25. 25.🍋 Why does the lemon writing turn brown with heat? (a) heat adds colour (b) the juice scorches first (c) paper turns lemony (d) the iron is brown
26. 26.🔍 Which is the odd one out? (a) reading the message (b) plugging in the iron (c) writing the message (d) dipping the cotton bud
27. 27.⚖️ 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 cotton bud (c) the kind of juice
28. 28.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) an adult with an iron (b) a cotton bud (c) a mirror (d) lemon juice
29. 29.🧺 Do we need lemon juice for the secret lemon message? (a) not needed (b) needed
30. 30.True or false: putting the iron away is a job a child can do. (a) True (b) False
31. 31.True or false: dipping the cotton bud is a job for an adult. (a) True (b) False
32. 32.⚖️ 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
33. 33.📘 The browning of lemon juice with heat is a ___ change. (a) magnetic (b) physical (c) musical (d) chemical
34. 34.🧺 Which of these is needed for the secret lemon message? (a) yeast (b) an adult with an iron (c) a magnet (d) a battery cell
35. 35.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the kind of juice”? (a) we measure it (b) we change it (c) we keep it the same
36. 36.True or false: yeast is not needed for the secret lemon message. (a) False (b) True
37. 37.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) an adult with an iron (b) a cotton bud (c) a magnet (d) a small bowl
38. 38.🔮 Predict: the adult irons for only one second. What happens? (a) it gets darker (b) writing turns green (c) writing stays faint (d) the paper floats
39. 39.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the iron setting”? (a) we keep it the same (b) we measure it (c) we change it
40. 40.🔮 Predict: you write with plain water instead of lemon juice. What appears after ironing? (a) blue words (b) dark brown words (c) a rainbow (d) almost nothing

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