Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 913 · 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) reading the message (b) putting the iron away (c) cutting the lemon (d) ironing the paper
2. 2.🧺 Which of these is needed for the secret lemon message? (a) a battery cell (b) a magnet (c) a small bowl (d) a mirror
3. 3.🍋 What colour does the lemon writing turn when an adult warms it? (a) blue (b) green (c) white (d) brown
4. 4.🍋 Secret message: who does this step — writing the message? (a) an adult does it (b) a child can do it
5. 5.🧺 Do we need a magnet for the secret lemon message? (a) not needed (b) needed
6. 6.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) wash your hands (b) skip washing (c) rub your eyes (d) lick your fingers
7. 7.🧺 Which of these is needed for the secret lemon message? (a) white paper (b) a magnet (c) a balloon (d) turmeric powder
8. 8.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) white paper (b) an adult with an iron (c) a magnet (d) a cotton bud
9. 9.🔮 Can the brown writing go back to being invisible? (a) yes, if shaken (b) yes, in the dark (c) no, it stays brown (d) yes, if cooled
10. 10.🧺 Which of these is not needed for the secret lemon message? (a) white paper (b) lemon juice (c) a cotton bud (d) a battery cell
11. 11.⚖️ 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 paper (c) the kind of juice
12. 12.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is what we measure? (a) the ironing time (b) the iron setting (c) the same paper (d) how dark the writing is
13. 13.🔮 Predict: you write with plain water instead of lemon juice. What appears after ironing? (a) blue words (b) almost nothing (c) a rainbow (d) dark brown words
14. 14.True or false: letting the paper dry is a job for an adult. (a) False (b) True
15. 15.True or false: a balloon is needed for the secret lemon message. (a) False (b) True
16. 16.🔍 Which is the odd one out? (a) cutting the lemon (b) reading the message (c) ironing the paper (d) putting the iron away
17. 17.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is the one thing we change? (a) the same paper (b) the ironing time (c) the iron setting (d) the kind of juice
18. 18.🧺 Do we need lemon juice for the secret lemon message? (a) not needed (b) needed
19. 19.True or false: lemon juice is needed for the secret lemon message. (a) False (b) True
20. 20.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a cotton bud (b) an adult with an iron (c) lemon juice (d) a battery cell
21. 21.🍋 Which of these steps is a job for an adult? (a) reading the message (b) writing the message (c) letting the paper dry (d) plugging in the iron
22. 22.🛟 Who should use the hot iron in the secret message experiment? (a) whoever is fastest (b) the youngest child (c) any child (d) only an adult
23. 23.🧺 Do we need an adult with an iron for the secret lemon message? (a) not needed (b) needed
24. 24.⚖️ 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
25. 25.🧺 Do we need a cotton bud for the secret lemon message? (a) not needed (b) needed
26. 26.🧺 Which of these is not needed for the secret lemon message? (a) white paper (b) a cotton bud (c) a balloon (d) lemon juice
27. 27.True or false: cutting the lemon is a job for an adult. (a) False (b) True
28. 28.True or false: yeast is not needed for the secret lemon message. (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) white paper (c) turmeric powder (d) lemon juice
30. 30.🧺 Which of these is not needed for the secret lemon message? (a) yeast (b) a cotton bud (c) a small bowl (d) lemon juice
31. 31.🧺 Do we need white paper for the secret lemon message? (a) not needed (b) needed
32. 32.🧺 Which of these is not needed for the secret lemon message? (a) an adult with an iron (b) lemon juice (c) a cotton bud (d) turmeric powder
33. 33.True or false: a balloon is not needed for the secret lemon message. (a) False (b) True
34. 34.True or false: writing the message is a job for an adult. (a) True (b) False
35. 35.🧺 Do we need a small bowl for the secret lemon message? (a) not needed (b) needed
36. 36.🔮 Predict: the adult irons for only one second. What happens? (a) the paper floats (b) writing stays faint (c) writing turns green (d) it gets darker
37. 37.🧺 Which of these is not needed for the secret lemon message? (a) lemon juice (b) a magnet (c) white paper (d) an adult with an iron
38. 38.True or false: ironing the paper is a job a child can do. (a) True (b) False
39. 39.🍋 Which of these steps is a job a child can do? (a) dipping the cotton bud (b) ironing the paper (c) cutting the lemon (d) putting the iron away
40. 40.📘 The browning of lemon juice with heat is a ___ change. (a) musical (b) magnetic (c) chemical (d) physical

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