Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 187 · 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 of these is needed for the secret lemon message? (a) a battery cell (b) a balloon (c) turmeric powder (d) lemon juice
2. 2.🛟 Who should use the hot iron in the secret message experiment? (a) whoever is fastest (b) any child (c) the youngest child (d) only an adult
3. 3.🍋 Which of these steps is a job for an adult? (a) dipping the cotton bud (b) writing the message (c) reading the message (d) plugging in the iron
4. 4.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) lick your fingers (b) skip washing (c) rub your eyes (d) wash your hands
5. 5.🔍 Which is the odd one out? (a) putting the iron away (b) dipping the cotton bud (c) ironing the paper (d) plugging in the iron
6. 6.🧺 Which of these is needed for the secret lemon message? (a) a mirror (b) white paper (c) turmeric powder (d) yeast
7. 7.True or false: a battery cell is not needed for the secret lemon message. (a) False (b) True
8. 8.True or false: putting the iron away is a job a child can do. (a) True (b) False
9. 9.🍋 Which of these steps is a job for an adult? (a) dipping the cotton bud (b) letting the paper dry (c) ironing the paper (d) reading the message
10. 10.🍋 What colour does the lemon writing turn when an adult warms it? (a) green (b) blue (c) brown (d) white
11. 11.True or false: a cotton bud is needed for the secret lemon message. (a) True (b) False
12. 12.True or false: plugging in the iron is a job a child can do. (a) True (b) False
13. 13.🔮 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
14. 14.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a small bowl (b) an adult with an iron (c) turmeric powder (d) a cotton bud
15. 15.🍋 Secret message: who does this step — plugging in the iron? (a) a child can do it (b) an adult does it
16. 16.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the ironing time”? (a) we measure it (b) we keep it the same (c) we change it
17. 17.🧺 Do we need lemon juice for the secret lemon message? (a) not needed (b) needed
18. 18.🧺 Which of these is not needed for the secret lemon message? (a) turmeric powder (b) a small bowl (c) lemon juice (d) white paper
19. 19.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is what we measure? (a) the same paper (b) the iron setting (c) the same cotton bud (d) how dark the writing is
20. 20.🔮 Predict: the adult irons for only one second. What happens? (a) writing stays faint (b) writing turns green (c) it gets darker (d) the paper floats
21. 21.🔍 Which is the odd one out? (a) plugging in the iron (b) reading the message (c) writing the message (d) dipping the cotton bud
22. 22.🧺 Which of these is not needed for the secret lemon message? (a) an adult with an iron (b) white paper (c) a battery cell (d) a cotton bud
23. 23.⚖️ 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
24. 24.True or false: cutting the lemon is a job a child can do. (a) False (b) True
25. 25.🧺 Do we need turmeric powder for the secret lemon message? (a) not needed (b) needed
26. 26.🛟 Why must children keep their fingers away from the iron? (a) it is sticky (b) it can burn skin (c) it is magnetic (d) it is cold
27. 27.🧺 Do we need a balloon for the secret lemon message? (a) not needed (b) needed
28. 28.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the iron setting”? (a) we change it (b) we measure it (c) we keep it the same
29. 29.True or false: a cotton bud is not needed for the secret lemon message. (a) True (b) False
30. 30.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the iron setting is the one thing we change. (a) True (b) False
31. 31.🧺 Do we need a cotton bud for the secret lemon message? (a) needed (b) not needed
32. 32.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a cotton bud (b) an adult with an iron (c) lemon juice (d) a balloon
33. 33.True or false: cutting the lemon is a job for an adult. (a) True (b) False
34. 34.🍋 Secret message: who does this step — writing the message? (a) a child can do it (b) an adult does it
35. 35.⚖️ 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
36. 36.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the kind of juice is kept the same. (a) True (b) False
37. 37.🔮 Can the brown writing go back to being invisible? (a) yes, if cooled (b) yes, in the dark (c) no, it stays brown (d) yes, if shaken
38. 38.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the iron setting is what we measure. (a) True (b) False
39. 39.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the same cotton bud is kept the same. (a) True (b) False
40. 40.True or false: a battery cell is needed for the secret lemon message. (a) True (b) False

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