Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 989 · 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) yes, if shaken (b) yes, if cooled (c) yes, in the dark (d) no, it stays brown
2. 2.🧺 Do we need a balloon for the secret lemon message? (a) not needed (b) needed
3. 3.True or false: turmeric powder is needed for the secret lemon message. (a) True (b) False
4. 4.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is what we measure? (a) the ironing time (b) the same paper (c) the kind of juice (d) how dark the writing is
5. 5.🧺 Do we need a mirror for the secret lemon message? (a) needed (b) not needed
6. 6.🔍 Which is the odd one out? (a) reading the message (b) dipping the cotton bud (c) plugging in the iron (d) letting the paper dry
7. 7.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the ironing time is kept the same. (a) True (b) False
8. 8.🛟 Who should use the hot iron in the secret message experiment? (a) the youngest child (b) any child (c) only an adult (d) whoever is fastest
9. 9.🧺 Do we need a small bowl for the secret lemon message? (a) not needed (b) needed
10. 10.True or false: a magnet is needed for the secret lemon message. (a) True (b) False
11. 11.True or false: putting the iron away is a job a child can do. (a) True (b) False
12. 12.True or false: white paper is needed for the secret lemon message. (a) False (b) True
13. 13.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) white paper (b) a cotton bud (c) turmeric powder (d) a small bowl
14. 14.⚖️ 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 change it (c) we measure it
15. 15.🔮 Predict: the adult irons for only one second. What happens? (a) writing turns green (b) it gets darker (c) the paper floats (d) writing stays faint
16. 16.🧺 Do we need yeast for the secret lemon message? (a) not needed (b) needed
17. 17.🧺 Which of these is not needed for the secret lemon message? (a) lemon juice (b) a cotton bud (c) an adult with an iron (d) yeast
18. 18.🔍 Which is the odd one out? (a) cutting the lemon (b) writing the message (c) putting the iron away (d) ironing the paper
19. 19.🧺 Which of these is needed for the secret lemon message? (a) a balloon (b) white paper (c) turmeric powder (d) yeast
20. 20.🧺 Do we need turmeric powder for the secret lemon message? (a) needed (b) not needed
21. 21.🍋 Secret message: who does this step — dipping the cotton bud? (a) an adult does it (b) a child can do it
22. 22.🍋 Which of these steps is a job a child can do? (a) cutting the lemon (b) plugging in the iron (c) ironing the paper (d) reading the message
23. 23.🍋 Secret message: who does this step — reading the message? (a) a child can do it (b) an adult does it
24. 24.🍋 Which of these steps is a job for an adult? (a) letting the paper dry (b) writing the message (c) dipping the cotton bud (d) ironing the paper
25. 25.🧺 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) lemon juice (d) white paper
26. 26.True or false: ironing the paper is a job a child can do. (a) False (b) True
27. 27.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the same paper”? (a) we keep it the same (b) we change it (c) we measure it
28. 28.🧺 Which of these is not needed for the secret lemon message? (a) white paper (b) a small bowl (c) a magnet (d) lemon juice
29. 29.True or false: cutting the lemon is a job a child can do. (a) False (b) True
30. 30.🍋 Secret message: who does this step — putting the iron away? (a) an adult does it (b) a child can do it
31. 31.🍋 Which of these steps is a job a child can do? (a) plugging in the iron (b) writing the message (c) putting the iron away (d) cutting the lemon
32. 32.🍋 What colour does the lemon writing turn when an adult warms it? (a) brown (b) white (c) blue (d) green
33. 33.🔍 Which is the odd one out? (a) plugging in the iron (b) ironing the paper (c) reading the message (d) cutting the lemon
34. 34.⚖️ 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 paper (c) the ironing time (d) the same cotton bud
35. 35.🧺 Do we need a battery cell for the secret lemon message? (a) needed (b) not needed
36. 36.True or false: yeast is not needed for the secret lemon message. (a) True (b) False
37. 37.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the kind of juice”? (a) we change it (b) we measure it (c) we keep it the same
38. 38.🔍 Which is the odd one out? (a) putting the iron away (b) plugging in the iron (c) letting the paper dry (d) ironing the paper
39. 39.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the same cotton bud”? (a) we change it (b) we measure it (c) we keep it the same
40. 40.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) an adult with an iron (b) white paper (c) a cotton bud (d) a magnet

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