Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 444 · 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.🧺 Do we need lemon juice for the secret lemon message? (a) not needed (b) needed
2. 2.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) white paper (b) lemon juice (c) a balloon (d) a cotton bud
3. 3.🍋 Secret message: who does this step — putting the iron away? (a) a child can do it (b) an adult does it
4. 4.⚖️ 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) how dark the writing is (c) the same paper (d) the ironing time
5. 5.🔮 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
6. 6.🍋 Secret message: who does this step — dipping the cotton bud? (a) an adult does it (b) a child can do it
7. 7.🍋 Which of these steps is a job a child can do? (a) letting the paper dry (b) putting the iron away (c) ironing the paper (d) plugging in the iron
8. 8.🛟 Why must children keep their fingers away from the iron? (a) it is cold (b) it is sticky (c) it can burn skin (d) it is magnetic
9. 9.True or false: a magnet is needed for the secret lemon message. (a) True (b) False
10. 10.🧺 Do we need white paper for the secret lemon message? (a) not needed (b) needed
11. 11.True or false: putting the iron away is a job for an adult. (a) False (b) True
12. 12.🛟 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
13. 13.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a battery cell (b) a small bowl (c) a cotton bud (d) lemon juice
14. 14.🍋 Which of these steps is a job a child can do? (a) putting the iron away (b) plugging in the iron (c) ironing the paper (d) writing the message
15. 15.⚖️ 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 keep it the same (c) we change it
16. 16.🧺 Which of these is needed for the secret lemon message? (a) turmeric powder (b) lemon juice (c) yeast (d) a balloon
17. 17.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the ironing time is what we measure. (a) True (b) False
18. 18.True or false: a cotton bud is needed for the secret lemon message. (a) True (b) False
19. 19.True or false: dipping the cotton bud is a job a child can do. (a) True (b) False
20. 20.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a cotton bud (b) white paper (c) lemon juice (d) a mirror
21. 21.🔍 Which is the odd one out? (a) dipping the cotton bud (b) reading the message (c) putting the iron away (d) letting the paper dry
22. 22.🧺 Which of these is needed for the secret lemon message? (a) a balloon (b) turmeric powder (c) a battery cell (d) white paper
23. 23.🔮 Can the brown writing go back to being invisible? (a) no, it stays brown (b) yes, in the dark (c) yes, if cooled (d) yes, if shaken
24. 24.🧺 Which of these is needed for the secret lemon message? (a) turmeric powder (b) a mirror (c) a balloon (d) an adult with an iron
25. 25.True or false: turmeric powder is needed for the secret lemon message. (a) False (b) True
26. 26.🍋 Which of these steps is a job for an adult? (a) putting the iron away (b) reading the message (c) writing the message (d) dipping the cotton bud
27. 27.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the ironing time is the one thing we change. (a) False (b) True
28. 28.True or false: plugging in the iron is a job a child can do. (a) True (b) False
29. 29.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: how dark the writing is is kept the same. (a) True (b) False
30. 30.🍋 Which of these steps is a job a child can do? (a) dipping the cotton bud (b) plugging in the iron (c) putting the iron away (d) cutting the lemon
31. 31.🔮 Predict: the adult irons for only one second. What happens? (a) writing turns green (b) the paper floats (c) writing stays faint (d) it gets darker
32. 32.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a magnet (b) a cotton bud (c) white paper (d) an adult with an iron
33. 33.🧺 Do we need a small bowl for the secret lemon message? (a) needed (b) not needed
34. 34.🍋 Why can’t you see the lemon writing once it dries? (a) dry juice is see-through (b) the ink is magnetic (c) the paper ate it (d) it turned into air
35. 35.🧺 Do we need a battery cell for the secret lemon message? (a) not needed (b) needed
36. 36.🍋 Secret message: who does this step — reading the message? (a) a child can do it (b) an adult does it
37. 37.True or false: writing the message is a job a child can do. (a) False (b) True
38. 38.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the same paper”? (a) we measure it (b) we keep it the same (c) we change it
39. 39.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) lick your fingers (b) wash your hands (c) skip washing (d) rub your eyes
40. 40.🍋 Why does the lemon writing turn brown with heat? (a) paper turns lemony (b) the juice scorches first (c) heat adds colour (d) the iron is brown

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