Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 398 · 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.🍋 Secret message: who does this step — ironing the paper? (a) a child can do it (b) an adult does it
2. 2.🧺 Do we need yeast for the secret lemon message? (a) needed (b) not needed
3. 3.🍋 Which of these steps is a job for an adult? (a) letting the paper dry (b) putting the iron away (c) reading the message (d) writing the message
4. 4.🧺 Do we need white paper for the secret lemon message? (a) needed (b) not needed
5. 5.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) rub your eyes (b) skip washing (c) lick your fingers (d) wash your hands
6. 6.🧺 Which of these is needed for the secret lemon message? (a) a mirror (b) a magnet (c) lemon juice (d) turmeric powder
7. 7.True or false: white paper is not needed for the secret lemon message. (a) True (b) False
8. 8.🍋 What colour does the lemon writing turn when an adult warms it? (a) green (b) blue (c) white (d) brown
9. 9.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a battery cell (b) an adult with an iron (c) a small bowl (d) lemon juice
10. 10.🔍 Which is the odd one out? (a) cutting the lemon (b) letting the paper dry (c) dipping the cotton bud (d) writing the message
11. 11.🔍 Which is the odd one out? (a) dipping the cotton bud (b) writing the message (c) letting the paper dry (d) ironing the paper
12. 12.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the kind of juice is what we measure. (a) True (b) False
13. 13.True or false: dipping the cotton bud is a job for an adult. (a) False (b) True
14. 14.⚖️ 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) how dark the writing is (c) the same cotton bud
15. 15.🍋 Secret message: who does this step — putting the iron away? (a) an adult does it (b) a child can do it
16. 16.🧺 Which of these is needed for the secret lemon message? (a) turmeric powder (b) a magnet (c) white paper (d) a battery cell
17. 17.🧺 Which of these is not needed for the secret lemon message? (a) a small bowl (b) a battery cell (c) an adult with an iron (d) lemon juice
18. 18.🛟 Why must children keep their fingers away from the iron? (a) it is magnetic (b) it is sticky (c) it can burn skin (d) it is cold
19. 19.True or false: putting the iron away is a job a child can do. (a) True (b) False
20. 20.🍋 Secret message: who does this step — writing the message? (a) an adult does it (b) a child can do it
21. 21.🧺 Do we need a balloon for the secret lemon message? (a) not needed (b) needed
22. 22.True or false: letting the paper dry is a job a child can do. (a) True (b) False
23. 23.True or false: plugging in the iron is a job a child can do. (a) False (b) True
24. 24.🍋 Which of these steps is a job for an adult? (a) reading the message (b) dipping the cotton bud (c) writing the message (d) ironing the paper
25. 25.🍋 Which of these steps is a job a child can do? (a) ironing the paper (b) cutting the lemon (c) writing the message (d) plugging in the iron
26. 26.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is the one thing we change? (a) the kind of juice (b) the same cotton bud (c) the iron setting (d) the same paper
27. 27.True or false: lemon juice is needed for the secret lemon message. (a) True (b) False
28. 28.True or false: white paper is needed for the secret lemon message. (a) False (b) True
29. 29.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the iron setting”? (a) we change it (b) we measure it (c) we keep it the same
30. 30.🔍 Which is the odd one out? (a) putting the iron away (b) plugging in the iron (c) cutting the lemon (d) letting the paper dry
31. 31.⚖️ 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
32. 32.⚖️ 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
33. 33.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: how dark the writing is is what we measure. (a) False (b) True
34. 34.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) lemon juice (b) an adult with an iron (c) a small bowl (d) a balloon
35. 35.True or false: plugging in the iron is a job for an adult. (a) False (b) True
36. 36.🍋 Why does the lemon writing turn brown with heat? (a) paper turns lemony (b) heat adds colour (c) the juice scorches first (d) the iron is brown
37. 37.🍋 Secret message: who does this step — reading the message? (a) an adult does it (b) a child can do it
38. 38.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a magnet (b) a cotton bud (c) lemon juice (d) an adult with an iron
39. 39.True or false: a magnet is needed for the secret lemon message. (a) False (b) True
40. 40.🧺 Do we need an adult with an iron for the secret lemon message? (a) not needed (b) needed

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