Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 774 · 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.⚖️ 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
2. 2.⚖️ 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
3. 3.🧺 Which of these is needed for the secret lemon message? (a) white paper (b) a magnet (c) a balloon (d) yeast
4. 4.🧺 Do we need yeast for the secret lemon message? (a) not needed (b) needed
5. 5.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the kind of juice is kept the same. (a) False (b) True
6. 6.🧺 Which of these is not needed for the secret lemon message? (a) a balloon (b) white paper (c) lemon juice (d) a cotton bud
7. 7.🔮 Predict: the adult irons for only one second. What happens? (a) writing stays faint (b) the paper floats (c) writing turns green (d) it gets darker
8. 8.⚖️ 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 cotton bud (c) how dark the writing is (d) the iron setting
9. 9.🧺 Do we need a battery cell for the secret lemon message? (a) not needed (b) needed
10. 10.🧺 Which of these is not needed for the secret lemon message? (a) an adult with an iron (b) a small bowl (c) white paper (d) turmeric powder
11. 11.True or false: letting the paper dry is a job for an adult. (a) False (b) True
12. 12.🧺 Do we need a cotton bud for the secret lemon message? (a) needed (b) not needed
13. 13.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) lick your fingers (b) skip washing (c) wash your hands (d) rub your eyes
14. 14.🍋 What colour does the lemon writing turn when an adult warms it? (a) blue (b) green (c) brown (d) white
15. 15.🍋 Secret message: who does this step — reading the message? (a) an adult does it (b) a child can do it
16. 16.🔮 Predict: you write with plain water instead of lemon juice. What appears after ironing? (a) blue words (b) almost nothing (c) a rainbow (d) dark brown words
17. 17.True or false: white paper is not needed for the secret lemon message. (a) False (b) True
18. 18.🍋 Secret message: who does this step — letting the paper dry? (a) an adult does it (b) a child can do it
19. 19.True or false: dipping the cotton bud is a job a child can do. (a) True (b) False
20. 20.🔍 Which is the odd one out? (a) plugging in the iron (b) putting the iron away (c) cutting the lemon (d) dipping the cotton bud
21. 21.🧺 Which of these is needed for the secret lemon message? (a) a small bowl (b) yeast (c) turmeric powder (d) a magnet
22. 22.🔍 Which is the odd one out? (a) dipping the cotton bud (b) ironing the paper (c) writing the message (d) letting the paper dry
23. 23.True or false: writing the message is a job a child can do. (a) True (b) False
24. 24.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “how dark the writing is”? (a) we keep it the same (b) we change it (c) we measure it
25. 25.⚖️ 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) True (b) False
26. 26.🧺 Do we need a mirror for the secret lemon message? (a) not needed (b) needed
27. 27.🍋 Secret message: who does this step — ironing the paper? (a) a child can do it (b) an adult does it
28. 28.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) white paper (b) lemon juice (c) a mirror (d) a small bowl
29. 29.🛟 Who should use the hot iron in the secret message experiment? (a) only an adult (b) whoever is fastest (c) any child (d) the youngest child
30. 30.🍋 Secret message: who does this step — dipping the cotton bud? (a) an adult does it (b) a child can do it
31. 31.🍋 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) reading the message
32. 32.🍋 Which of these steps is a job a child can do? (a) ironing the paper (b) writing the message (c) putting the iron away (d) plugging in the iron
33. 33.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the ironing time is kept the same. (a) False (b) True
34. 34.🧺 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
35. 35.📘 The browning of lemon juice with heat is a ___ change. (a) chemical (b) musical (c) physical (d) magnetic
36. 36.🧺 Which of these is not needed for the secret lemon message? (a) a cotton bud (b) a mirror (c) a small bowl (d) an adult with an iron
37. 37.True or false: a magnet is not needed for the secret lemon message. (a) False (b) True
38. 38.🍋 Which of these steps is a job a child can do? (a) dipping the cotton bud (b) plugging in the iron (c) ironing the paper (d) cutting the lemon
39. 39.🔍 Which is the odd one out? (a) dipping the cotton bud (b) putting the iron away (c) letting the paper dry (d) reading the message
40. 40.True or false: an adult with an iron is needed for the secret lemon message. (a) False (b) True

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