Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 487 · 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.🍋 What colour does the lemon writing turn when an adult warms it? (a) blue (b) white (c) green (d) brown
2. 2.🧺 Do we need a magnet for the secret lemon message? (a) not needed (b) needed
3. 3.🛟 Why must children keep their fingers away from the iron? (a) it is magnetic (b) it is sticky (c) it can burn skin (d) it is cold
4. 4.True or false: yeast is needed for the secret lemon message. (a) True (b) False
5. 5.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) lemon juice (b) yeast (c) a cotton bud (d) a small bowl
6. 6.⚖️ 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 same cotton bud (c) how dark the writing is (d) the ironing time
7. 7.🍋 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
8. 8.🛟 Who should use the hot iron in the secret message experiment? (a) any child (b) the youngest child (c) whoever is fastest (d) only an adult
9. 9.True or false: white paper is needed for the secret lemon message. (a) False (b) True
10. 10.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) lick your fingers (b) rub your eyes (c) wash your hands (d) skip washing
11. 11.🍋 Which of these steps is a job for an adult? (a) reading the message (b) letting the paper dry (c) writing the message (d) cutting the lemon
12. 12.True or false: plugging in the iron is a job a child can do. (a) False (b) True
13. 13.🍋 Secret message: who does this step — putting the iron away? (a) a child can do it (b) an adult does it
14. 14.🍋 Which of these steps is a job a child can do? (a) cutting the lemon (b) ironing the paper (c) putting the iron away (d) writing the message
15. 15.True or false: a balloon is not needed for the secret lemon message. (a) False (b) True
16. 16.🔍 Which is the odd one out? (a) ironing the paper (b) cutting the lemon (c) writing the message (d) plugging in the iron
17. 17.🍋 Which of these steps is a job a child can do? (a) putting the iron away (b) ironing the paper (c) letting the paper dry (d) cutting the lemon
18. 18.⚖️ 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
19. 19.🧺 Which of these is needed for the secret lemon message? (a) a magnet (b) lemon juice (c) yeast (d) a balloon
20. 20.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) lemon juice (b) a small bowl (c) an adult with an iron (d) a magnet
21. 21.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is the one thing we change? (a) how dark the writing is (b) the kind of juice (c) the same cotton bud (d) the iron setting
22. 22.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is kept the same? (a) the kind of juice (b) the same paper (c) how dark the writing is
23. 23.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the ironing time is kept the same. (a) False (b) True
24. 24.True or false: letting the paper dry is a job for an adult. (a) False (b) True
25. 25.🧺 Do we need lemon juice for the secret lemon message? (a) not needed (b) needed
26. 26.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the iron setting”? (a) we measure it (b) we keep it the same (c) we change it
27. 27.True or false: white paper is not needed for the secret lemon message. (a) True (b) False
28. 28.🧺 Do we need yeast for the secret lemon message? (a) not needed (b) needed
29. 29.⚖️ 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 keep it the same (c) we measure it
30. 30.True or false: writing the message is a job a child can do. (a) False (b) True
31. 31.🧺 Do we need a mirror for the secret lemon message? (a) needed (b) not needed
32. 32.🍋 Secret message: who does this step — ironing the paper? (a) an adult does it (b) a child can do it
33. 33.⚖️ 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) False (b) True
34. 34.🍋 Which of these steps is a job for an adult? (a) reading the message (b) putting the iron away (c) writing the message (d) letting the paper dry
35. 35.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a battery cell (b) a small bowl (c) white paper (d) an adult with an iron
36. 36.⚖️ 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
37. 37.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the kind of juice is what we measure. (a) True (b) False
38. 38.🍋 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) plugging in the iron
39. 39.🔮 Predict: the adult irons for only one second. What happens? (a) it gets darker (b) the paper floats (c) writing turns green (d) writing stays faint
40. 40.🔍 Which is the odd one out? (a) ironing the paper (b) letting the paper dry (c) writing the message (d) dipping the cotton bud

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