Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 959 · 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.True or false: plugging in the iron is a job for an adult. (a) True (b) False
2. 2.⚖️ 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
3. 3.🍋 Which of these steps is a job for an adult? (a) ironing the paper (b) reading the message (c) letting the paper dry (d) dipping the cotton bud
4. 4.True or false: a small bowl is needed for the secret lemon message. (a) False (b) True
5. 5.True or false: a magnet is needed for the secret lemon message. (a) False (b) True
6. 6.🔍 Which is the odd one out? (a) letting the paper dry (b) reading the message (c) dipping the cotton bud (d) putting the iron away
7. 7.🔍 Which is the odd one out? (a) putting the iron away (b) plugging in the iron (c) cutting the lemon (d) letting the paper dry
8. 8.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a cotton bud (b) white paper (c) a magnet (d) lemon juice
9. 9.🧺 Which of these is needed for the secret lemon message? (a) a mirror (b) yeast (c) turmeric powder (d) white paper
10. 10.🍋 Secret message: who does this step — writing the message? (a) an adult does it (b) a child can do it
11. 11.🧺 Do we need a mirror for the secret lemon message? (a) needed (b) not needed
12. 12.🧺 Do we need a magnet for the secret lemon message? (a) not needed (b) needed
13. 13.🍋 Which of these steps is a job for an adult? (a) writing the message (b) letting the paper dry (c) dipping the cotton bud (d) cutting the lemon
14. 14.🔍 Which is the odd one out? (a) dipping the cotton bud (b) ironing the paper (c) letting the paper dry (d) writing the message
15. 15.🍋 Which of these steps is a job a child can do? (a) cutting the lemon (b) ironing the paper (c) letting the paper dry (d) plugging in the iron
16. 16.🍋 What colour does the lemon writing turn when an adult warms it? (a) green (b) white (c) blue (d) brown
17. 17.True or false: a cotton bud is needed for the secret lemon message. (a) True (b) False
18. 18.🔮 Can the brown writing go back to being invisible? (a) no, it stays brown (b) yes, in the dark (c) yes, if shaken (d) yes, if cooled
19. 19.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the same paper is what we measure. (a) False (b) True
20. 20.🔍 Which is the odd one out? (a) writing the message (b) ironing the paper (c) plugging in the iron (d) cutting the lemon
21. 21.🛟 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
22. 22.🍋 Which of these steps is a job for an adult? (a) writing the message (b) plugging in the iron (c) letting the paper dry (d) dipping the cotton bud
23. 23.🛟 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
24. 24.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the ironing time”? (a) we change it (b) we measure it (c) we keep it the same
25. 25.🍋 Which of these steps is a job a child can do? (a) reading the message (b) plugging in the iron (c) ironing the paper (d) putting the iron away
26. 26.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a small bowl (b) white paper (c) a battery cell (d) an adult with an iron
27. 27.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the same cotton bud”? (a) we measure it (b) we keep it the same (c) we change it
28. 28.🧺 Which of these is not needed for the secret lemon message? (a) white paper (b) turmeric powder (c) lemon juice (d) a small bowl
29. 29.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the same cotton bud is what we measure. (a) False (b) True
30. 30.🧺 Do we need a cotton bud for the secret lemon message? (a) needed (b) not needed
31. 31.⚖️ 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
32. 32.⚖️ 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
33. 33.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is what we measure? (a) the same cotton bud (b) how dark the writing is (c) the kind of juice (d) the ironing time
34. 34.🍋 Why can’t you see the lemon writing once it dries? (a) the paper ate it (b) dry juice is see-through (c) it turned into air (d) the ink is magnetic
35. 35.🧺 Which of these is needed for the secret lemon message? (a) a small bowl (b) a magnet (c) a balloon (d) a battery cell
36. 36.🍋 Why does the lemon writing turn brown with heat? (a) the juice scorches first (b) paper turns lemony (c) heat adds colour (d) the iron is brown
37. 37.🧺 Which of these is needed for the secret lemon message? (a) a mirror (b) a cotton bud (c) a magnet (d) yeast
38. 38.🧺 Do we need yeast for the secret lemon message? (a) not needed (b) needed
39. 39.⚖️ 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
40. 40.🍋 Secret message: who does this step — plugging in the iron? (a) an adult does it (b) a child can do it

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