Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 937 · 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 steps is a job a child can do? (a) ironing the paper (b) putting the iron away (c) dipping the cotton bud (d) cutting the lemon
2. 2.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the kind of juice”? (a) we keep it the same (b) we change it (c) we measure it
3. 3.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a magnet (b) a small bowl (c) white paper (d) lemon juice
4. 4.True or false: cutting the lemon is a job a child can do. (a) True (b) False
5. 5.🍋 Secret message: who does this step — writing the message? (a) a child can do it (b) an adult does it
6. 6.🛟 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
7. 7.🧺 Which of these is needed for the secret lemon message? (a) turmeric powder (b) a mirror (c) a cotton bud (d) a magnet
8. 8.🔍 Which is the odd one out? (a) cutting the lemon (b) putting the iron away (c) ironing the paper (d) dipping the cotton bud
9. 9.True or false: a magnet is needed for the secret lemon message. (a) False (b) True
10. 10.True or false: yeast is not needed for the secret lemon message. (a) True (b) False
11. 11.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) skip washing (b) rub your eyes (c) wash your hands (d) lick your fingers
12. 12.True or false: lemon juice is needed for the secret lemon message. (a) True (b) False
13. 13.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “how dark the writing is”? (a) we change it (b) we measure it (c) we keep it the same
14. 14.True or false: a small bowl is not needed for the secret lemon message. (a) True (b) False
15. 15.🍋 Which of these steps is a job a child can do? (a) cutting the lemon (b) plugging in the iron (c) ironing the paper (d) writing the message
16. 16.🧺 Which of these is not needed for the secret lemon message? (a) a cotton bud (b) a mirror (c) a small bowl (d) lemon juice
17. 17.⚖️ 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
18. 18.🛟 Who should use the hot iron in the secret message experiment? (a) the youngest child (b) whoever is fastest (c) only an adult (d) any child
19. 19.⚖️ 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) the same cotton bud (c) the same paper (d) how dark the writing is
20. 20.🍋 Which of these steps is a job for an adult? (a) dipping the cotton bud (b) plugging in the iron (c) writing the message (d) reading the message
21. 21.🍋 Secret message: who does this step — plugging in the iron? (a) a child can do it (b) an adult does it
22. 22.📘 The browning of lemon juice with heat is a ___ change. (a) musical (b) physical (c) chemical (d) magnetic
23. 23.🧺 Do we need a cotton bud for the secret lemon message? (a) not needed (b) needed
24. 24.🧺 Do we need white paper for the secret lemon message? (a) not needed (b) needed
25. 25.🍋 Secret message: who does this step — putting the iron away? (a) a child can do it (b) an adult does it
26. 26.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a cotton bud (b) a mirror (c) an adult with an iron (d) lemon juice
27. 27.🧺 Do we need an adult with an iron for the secret lemon message? (a) needed (b) not needed
28. 28.⚖️ 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
29. 29.🧺 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 balloon (d) white paper
30. 30.🍋 Which of these steps is a job a child can do? (a) ironing the paper (b) putting the iron away (c) plugging in the iron (d) letting the paper dry
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.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the same paper”? (a) we keep it the same (b) we change it (c) we measure it
33. 33.True or false: a balloon is needed for the secret lemon message. (a) True (b) False
34. 34.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) an adult with an iron (b) white paper (c) lemon juice (d) yeast
35. 35.🍋 Secret message: who does this step — dipping the cotton bud? (a) an adult does it (b) a child can do it
36. 36.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is kept the same? (a) the iron setting (b) how dark the writing is (c) the kind of juice
37. 37.🧺 Which of these is not needed for the secret lemon message? (a) an adult with an iron (b) a magnet (c) a cotton bud (d) lemon juice
38. 38.🍋 Why can’t you see the lemon writing once it dries? (a) the ink is magnetic (b) it turned into air (c) dry juice is see-through (d) the paper ate it
39. 39.True or false: turmeric powder is not needed for the secret lemon message. (a) False (b) True
40. 40.⚖️ 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 ironing time (c) how dark the writing is

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