Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 178 · 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.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a balloon (b) an adult with an iron (c) a cotton bud (d) lemon juice
2. 2.🧺 Do we need lemon juice for the secret lemon message? (a) not needed (b) needed
3. 3.True or false: a battery cell is not needed for the secret lemon message. (a) False (b) True
4. 4.🛟 Who should use the hot iron in the secret message experiment? (a) only an adult (b) the youngest child (c) whoever is fastest (d) any child
5. 5.🍋 Which of these steps is a job a child can do? (a) putting the iron away (b) dipping the cotton bud (c) cutting the lemon (d) ironing the paper
6. 6.🍋 Which of these steps is a job for an adult? (a) reading the message (b) letting the paper dry (c) plugging in the iron (d) writing the message
7. 7.True or false: lemon juice is needed for the secret lemon message. (a) False (b) True
8. 8.True or false: dipping the cotton bud is a job a child can do. (a) True (b) False
9. 9.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is what we measure? (a) the iron setting (b) the ironing time (c) how dark the writing is (d) the same cotton bud
10. 10.🍋 Which of these steps is a job for an adult? (a) reading the message (b) dipping the cotton bud (c) writing the message (d) cutting the lemon
11. 11.🔮 Predict: the adult irons for only one second. What happens? (a) it gets darker (b) writing stays faint (c) writing turns green (d) the paper floats
12. 12.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) rub your eyes (b) wash your hands (c) skip washing (d) lick your fingers
13. 13.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is the one thing we change? (a) the same cotton bud (b) the iron setting (c) the same paper (d) the kind of juice
14. 14.True or false: cutting the lemon is a job a child can do. (a) False (b) True
15. 15.⚖️ 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
16. 16.🍋 Secret message: who does this step — dipping the cotton bud? (a) an adult does it (b) a child can do it
17. 17.True or false: ironing the paper is a job a child can do. (a) True (b) False
18. 18.🍋 Secret message: who does this step — cutting the lemon? (a) a child can do it (b) an adult does it
19. 19.🍋 Which of these steps is a job for an adult? (a) letting the paper dry (b) reading the message (c) dipping the cotton bud (d) putting the iron away
20. 20.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) white paper (b) a cotton bud (c) a small bowl (d) a battery cell
21. 21.🍋 Why does the lemon writing turn brown with heat? (a) the iron is brown (b) heat adds colour (c) the juice scorches first (d) paper turns lemony
22. 22.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is kept the same? (a) the iron setting (b) the kind of juice (c) how dark the writing is
23. 23.🔍 Which is the odd one out? (a) cutting the lemon (b) putting the iron away (c) ironing the paper (d) letting the paper dry
24. 24.True or false: writing the message is a job for an adult. (a) False (b) True
25. 25.True or false: lemon juice is not needed for the secret lemon message. (a) True (b) False
26. 26.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the kind of juice is kept the same. (a) False (b) True
27. 27.⚖️ 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
28. 28.🧺 Which of these is not needed for the secret lemon message? (a) an adult with an iron (b) lemon juice (c) white paper (d) a balloon
29. 29.🧺 Which of these is needed for the secret lemon message? (a) a balloon (b) a magnet (c) an adult with an iron (d) a battery cell
30. 30.🛟 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
31. 31.⚖️ 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
32. 32.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the same cotton bud”? (a) we keep it the same (b) we measure it (c) we change it
33. 33.🔮 Can the brown writing go back to being invisible? (a) yes, in the dark (b) yes, if cooled (c) yes, if shaken (d) no, it stays brown
34. 34.🧺 Do we need a small bowl for the secret lemon message? (a) needed (b) not needed
35. 35.🧺 Which of these is not needed for the secret lemon message? (a) a small bowl (b) a mirror (c) a cotton bud (d) lemon juice
36. 36.🔍 Which is the odd one out? (a) cutting the lemon (b) putting the iron away (c) writing the message (d) ironing the paper
37. 37.🍋 Which of these steps is a job a child can do? (a) ironing the paper (b) letting the paper dry (c) plugging in the iron (d) cutting the lemon
38. 38.True or false: reading the message is a job a child can do. (a) False (b) True
39. 39.🧺 Which of these is needed for the secret lemon message? (a) a mirror (b) white paper (c) a magnet (d) a balloon
40. 40.True or false: a small bowl is not needed for the secret lemon message. (a) True (b) False

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