Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 979 · 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.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) skip washing (b) lick your fingers (c) rub your eyes (d) wash your hands
2. 2.True or false: dipping the cotton bud is a job for an adult. (a) False (b) True
3. 3.🍋 What colour does the lemon writing turn when an adult warms it? (a) green (b) blue (c) brown (d) white
4. 4.🧺 Do we need an adult with an iron for the secret lemon message? (a) not needed (b) needed
5. 5.🍋 Secret message: who does this step — reading the message? (a) an adult does it (b) a child can do it
6. 6.🧺 Which of these is needed for the secret lemon message? (a) a balloon (b) lemon juice (c) turmeric powder (d) a battery cell
7. 7.🧺 Do we need a mirror for the secret lemon message? (a) not needed (b) needed
8. 8.True or false: plugging in the iron is a job a child can do. (a) True (b) False
9. 9.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a small bowl (b) white paper (c) a magnet (d) an adult with an iron
10. 10.🍋 Which of these steps is a job a child can do? (a) plugging in the iron (b) putting the iron away (c) writing the message (d) cutting the lemon
11. 11.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “how dark the writing is”? (a) we measure it (b) we change it (c) we keep it the same
12. 12.⚖️ 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 iron setting (d) how dark the writing is
13. 13.True or false: ironing the paper is a job for an adult. (a) True (b) False
14. 14.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) white paper (b) a battery cell (c) a small bowl (d) lemon juice
15. 15.🧺 Do we need turmeric powder for the secret lemon message? (a) not needed (b) needed
16. 16.🛟 Who should use the hot iron in the secret message experiment? (a) whoever is fastest (b) the youngest child (c) only an adult (d) any child
17. 17.🧺 Do we need a magnet for the secret lemon message? (a) not needed (b) needed
18. 18.🧺 Which of these is not needed for the secret lemon message? (a) white paper (b) a cotton bud (c) a battery cell (d) a small bowl
19. 19.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a balloon (b) lemon juice (c) a cotton bud (d) an adult with an iron
20. 20.🍋 Which of these steps is a job for an adult? (a) dipping the cotton bud (b) letting the paper dry (c) reading the message (d) ironing the paper
21. 21.🧺 Do we need white paper for the secret lemon message? (a) needed (b) not needed
22. 22.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is kept the same? (a) how dark the writing is (b) the same cotton bud (c) the kind of juice
23. 23.🔮 Predict: the adult irons for only one second. What happens? (a) writing turns green (b) it gets darker (c) writing stays faint (d) the paper floats
24. 24.True or false: a balloon is needed for the secret lemon message. (a) True (b) False
25. 25.🔍 Which is the odd one out? (a) dipping the cotton bud (b) writing the message (c) cutting the lemon (d) letting the paper dry
26. 26.🧺 Do we need a balloon for the secret lemon message? (a) not needed (b) needed
27. 27.True or false: yeast is not needed for the secret lemon message. (a) False (b) True
28. 28.🔍 Which is the odd one out? (a) putting the iron away (b) cutting the lemon (c) plugging in the iron (d) writing the message
29. 29.True or false: a mirror is needed for the secret lemon message. (a) True (b) False
30. 30.⚖️ 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
31. 31.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the kind of juice is what we measure. (a) False (b) True
32. 32.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the iron setting is kept the same. (a) True (b) False
33. 33.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) lemon juice (b) white paper (c) turmeric powder (d) a cotton bud
34. 34.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the same cotton bud”? (a) we change it (b) we measure it (c) we keep it the same
35. 35.🧺 Which of these is needed for the secret lemon message? (a) a mirror (b) white paper (c) a balloon (d) a magnet
36. 36.🔍 Which is the odd one out? (a) dipping the cotton bud (b) ironing the paper (c) putting the iron away (d) plugging in the iron
37. 37.🧺 Which of these is not needed for the secret lemon message? (a) yeast (b) an adult with an iron (c) white paper (d) a small bowl
38. 38.🧺 Which of these is needed for the secret lemon message? (a) yeast (b) turmeric powder (c) a balloon (d) a small bowl
39. 39.🧺 Which of these is not needed for the secret lemon message? (a) white paper (b) a balloon (c) a cotton bud (d) a small bowl
40. 40.🧺 Do we need a battery cell for the secret lemon message? (a) not needed (b) needed

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