Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 463 · 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.🔮 Can the brown writing go back to being invisible? (a) no, it stays brown (b) yes, if cooled (c) yes, if shaken (d) yes, in the dark
2. 2.🔍 Which is the odd one out? (a) letting the paper dry (b) writing the message (c) dipping the cotton bud (d) plugging in the iron
3. 3.⚖️ 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
4. 4.True or false: lemon juice is needed for the secret lemon message. (a) True (b) False
5. 5.🧺 Which of these is needed for the secret lemon message? (a) a magnet (b) a balloon (c) a small bowl (d) a battery cell
6. 6.⚖️ 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
7. 7.🔮 Predict: you write with plain water instead of lemon juice. What appears after ironing? (a) dark brown words (b) blue words (c) a rainbow (d) almost nothing
8. 8.True or false: a magnet is needed for the secret lemon message. (a) True (b) False
9. 9.⚖️ 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 cotton bud
10. 10.🧺 Do we need a mirror for the secret lemon message? (a) needed (b) not needed
11. 11.🛟 Who should use the hot iron in the secret message experiment? (a) any child (b) only an adult (c) the youngest child (d) whoever is fastest
12. 12.True or false: lemon juice is not needed for the secret lemon message. (a) False (b) True
13. 13.🍋 What colour does the lemon writing turn when an adult warms it? (a) white (b) brown (c) green (d) blue
14. 14.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a battery cell (b) an adult with an iron (c) a cotton bud (d) lemon juice
15. 15.🍋 Which of these steps is a job a child can do? (a) putting the iron away (b) dipping the cotton bud (c) cutting the lemon (d) ironing the paper
16. 16.True or false: a small bowl is not needed for the secret lemon message. (a) True (b) False
17. 17.🧺 Which of these is not needed for the secret lemon message? (a) an adult with an iron (b) lemon juice (c) a cotton bud (d) turmeric powder
18. 18.True or false: a balloon is needed for the secret lemon message. (a) False (b) True
19. 19.🛟 Why must children keep their fingers away from the iron? (a) it is magnetic (b) it is sticky (c) it is cold (d) it can burn skin
20. 20.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) rub your eyes (b) wash your hands (c) skip washing (d) lick your fingers
21. 21.True or false: white paper is needed for the secret lemon message. (a) False (b) True
22. 22.⚖️ 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
23. 23.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the same paper is kept the same. (a) False (b) True
24. 24.True or false: an adult with an iron is not needed for the secret lemon message. (a) False (b) True
25. 25.🍋 Secret message: who does this step — ironing the paper? (a) a child can do it (b) an adult does it
26. 26.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the iron setting is what we measure. (a) False (b) True
27. 27.🧺 Which of these is needed for the secret lemon message? (a) a mirror (b) a cotton bud (c) turmeric powder (d) a magnet
28. 28.🧺 Do we need a magnet for the secret lemon message? (a) not needed (b) needed
29. 29.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) lemon juice (b) a magnet (c) an adult with an iron (d) a cotton bud
30. 30.🔍 Which is the odd one out? (a) putting the iron away (b) cutting the lemon (c) ironing the paper (d) dipping the cotton bud
31. 31.🧺 Which of these is not needed for the secret lemon message? (a) a magnet (b) white paper (c) a cotton bud (d) lemon juice
32. 32.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the kind of juice is what we measure. (a) False (b) True
33. 33.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: how dark the writing is is the one thing we change. (a) False (b) True
34. 34.True or false: an adult with an iron is needed for the secret lemon message. (a) True (b) False
35. 35.🧺 Do we need lemon juice for the secret lemon message? (a) not needed (b) needed
36. 36.🧺 Do we need yeast for the secret lemon message? (a) not needed (b) needed
37. 37.True or false: dipping the cotton bud is a job for an adult. (a) True (b) False
38. 38.🧺 Which of these is not needed for the secret lemon message? (a) lemon juice (b) yeast (c) an adult with an iron (d) a cotton bud
39. 39.🍋 Secret message: who does this step — putting the iron away? (a) an adult does it (b) a child can do it
40. 40.🔍 Which is the odd one out? (a) ironing the paper (b) writing the message (c) reading the message (d) dipping the cotton bud

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