Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 657 · 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 an adult with an iron for the secret lemon message? (a) not needed (b) needed
2. 2.True or false: a mirror is needed for the secret lemon message. (a) False (b) True
3. 3.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is kept the same? (a) the same paper (b) the kind of juice (c) how dark the writing is
4. 4.True or false: reading the message is a job for an adult. (a) True (b) False
5. 5.True or false: an adult with an iron is needed for the secret lemon message. (a) False (b) True
6. 6.⚖️ 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
7. 7.🍋 Which of these steps is a job for an adult? (a) writing the message (b) reading the message (c) dipping the cotton bud (d) plugging in the iron
8. 8.⚖️ 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
9. 9.True or false: cutting the lemon is a job a child can do. (a) False (b) True
10. 10.True or false: a small bowl is needed for the secret lemon message. (a) True (b) False
11. 11.🧺 Which of these is needed for the secret lemon message? (a) a magnet (b) lemon juice (c) a balloon (d) a battery cell
12. 12.🧺 Which of these is needed for the secret lemon message? (a) turmeric powder (b) a mirror (c) a balloon (d) a small bowl
13. 13.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a small bowl (b) a cotton bud (c) a mirror (d) white paper
14. 14.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: how dark the writing is is the one thing we change. (a) True (b) False
15. 15.True or false: dipping the cotton bud is a job a child can do. (a) True (b) False
16. 16.🔍 Which is the odd one out? (a) putting the iron away (b) cutting the lemon (c) plugging in the iron (d) dipping the cotton bud
17. 17.📘 The browning of lemon juice with heat is a ___ change. (a) magnetic (b) chemical (c) physical (d) musical
18. 18.🧺 Which of these is not needed for the secret lemon message? (a) an adult with an iron (b) lemon juice (c) turmeric powder (d) a small bowl
19. 19.🛟 Why must children keep their fingers away from the iron? (a) it is cold (b) it can burn skin (c) it is sticky (d) it is magnetic
20. 20.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the iron setting is kept the same. (a) False (b) True
21. 21.True or false: a battery cell is not needed for the secret lemon message. (a) True (b) False
22. 22.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) rub your eyes (b) wash your hands (c) lick your fingers (d) skip washing
23. 23.🧺 Do we need a battery cell for the secret lemon message? (a) needed (b) not needed
24. 24.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a cotton bud (b) a battery cell (c) white paper (d) an adult with an iron
25. 25.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the same paper is the one thing we change. (a) False (b) True
26. 26.🧺 Which of these is not needed for the secret lemon message? (a) a cotton bud (b) lemon juice (c) a small bowl (d) a magnet
27. 27.⚖️ 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
28. 28.🍋 Secret message: who does this step — cutting the lemon? (a) an adult does it (b) a child can do it
29. 29.🍋 Which of these steps is a job for an adult? (a) letting the paper dry (b) writing the message (c) putting the iron away (d) reading the message
30. 30.🛟 Who should use the hot iron in the secret message experiment? (a) any child (b) only an adult (c) whoever is fastest (d) the youngest child
31. 31.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) turmeric powder (b) lemon juice (c) a cotton bud (d) a small bowl
32. 32.True or false: cutting the lemon is a job for an adult. (a) True (b) False
33. 33.🔮 Predict: you write with plain water instead of lemon juice. What appears after ironing? (a) blue words (b) a rainbow (c) dark brown words (d) almost nothing
34. 34.⚖️ 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
35. 35.🔍 Which is the odd one out? (a) reading the message (b) plugging in the iron (c) cutting the lemon (d) putting the iron away
36. 36.True or false: a magnet is needed for the secret lemon message. (a) True (b) False
37. 37.🍋 Which of these steps is a job a child can do? (a) writing the message (b) plugging in the iron (c) ironing the paper (d) putting the iron away
38. 38.🍋 Why can’t you see the lemon writing once it dries? (a) dry juice is see-through (b) it turned into air (c) the paper ate it (d) the ink is magnetic
39. 39.🔍 Which is the odd one out? (a) reading the message (b) writing the message (c) letting the paper dry (d) putting the iron away
40. 40.🧺 Do we need lemon juice for the secret lemon message? (a) not needed (b) needed

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