Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 177 · 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 is needed for the secret lemon message? (a) white paper (b) turmeric powder (c) a balloon (d) a magnet
2. 2.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “how dark the writing is”? (a) we keep it the same (b) we measure it (c) we change it
3. 3.🔍 Which is the odd one out? (a) reading the message (b) plugging in the iron (c) dipping the cotton bud (d) writing the message
4. 4.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the ironing time is what we measure. (a) False (b) True
5. 5.True or false: ironing the paper is a job a child can do. (a) False (b) True
6. 6.🛟 Why must children keep their fingers away from the iron? (a) it is sticky (b) it can burn skin (c) it is cold (d) it is magnetic
7. 7.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) an adult with an iron (b) a cotton bud (c) turmeric powder (d) lemon juice
8. 8.🔍 Which is the odd one out? (a) plugging in the iron (b) dipping the cotton bud (c) ironing the paper (d) cutting the lemon
9. 9.🍋 Secret message: who does this step — writing the message? (a) an adult does it (b) a child can do it
10. 10.🛟 Who should use the hot iron in the secret message experiment? (a) the youngest child (b) any child (c) only an adult (d) whoever is fastest
11. 11.🧺 Do we need a balloon for the secret lemon message? (a) needed (b) not needed
12. 12.🍋 What colour does the lemon writing turn when an adult warms it? (a) white (b) green (c) brown (d) blue
13. 13.🍋 Which of these steps is a job for an adult? (a) ironing the paper (b) letting the paper dry (c) reading the message (d) writing the message
14. 14.True or false: lemon juice is needed for the secret lemon message. (a) True (b) False
15. 15.True or false: reading the message is a job a child can do. (a) False (b) True
16. 16.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is kept the same? (a) the ironing time (b) the kind of juice (c) how dark the writing is
17. 17.True or false: putting the iron away is a job a child can do. (a) False (b) True
18. 18.🔮 Predict: you write with plain water instead of lemon juice. What appears after ironing? (a) dark brown words (b) blue words (c) almost nothing (d) a rainbow
19. 19.True or false: a magnet is not needed for the secret lemon message. (a) True (b) False
20. 20.🍋 Which of these steps is a job a child can do? (a) putting the iron away (b) ironing the paper (c) writing the message (d) cutting the lemon
21. 21.⚖️ 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
22. 22.🔮 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
23. 23.🍋 Which of these steps is a job a child can do? (a) ironing the paper (b) reading the message (c) plugging in the iron (d) putting the iron away
24. 24.True or false: a mirror is not needed for the secret lemon message. (a) False (b) True
25. 25.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a small bowl (b) a balloon (c) white paper (d) an adult with an iron
26. 26.🧺 Do we need turmeric powder for the secret lemon message? (a) needed (b) not needed
27. 27.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is the one thing we change? (a) the ironing time (b) how dark the writing is (c) the kind of juice (d) the same cotton bud
28. 28.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) rub your eyes (b) lick your fingers (c) skip washing (d) wash your hands
29. 29.🍋 Secret message: who does this step — reading the message? (a) an adult does it (b) a child can do it
30. 30.True or false: yeast is needed for the secret lemon message. (a) False (b) True
31. 31.🍋 Why does the lemon writing turn brown with heat? (a) heat adds colour (b) the iron is brown (c) the juice scorches first (d) paper turns lemony
32. 32.🍋 Which of these steps is a job for an adult? (a) letting the paper dry (b) cutting the lemon (c) reading the message (d) dipping the cotton bud
33. 33.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) an adult with an iron (b) a magnet (c) a cotton bud (d) lemon juice
34. 34.🧺 Do we need a magnet for the secret lemon message? (a) needed (b) not needed
35. 35.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the iron setting”? (a) we measure it (b) we keep it the same (c) we change it
36. 36.🍋 Secret message: who does this step — putting the iron away? (a) a child can do it (b) an adult does it
37. 37.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a cotton bud (b) lemon juice (c) a small bowl (d) a mirror
38. 38.🧺 Do we need an adult with an iron for the secret lemon message? (a) needed (b) not needed
39. 39.True or false: a cotton bud is not needed for the secret lemon message. (a) False (b) True
40. 40.🍋 Secret message: who does this step — cutting the lemon? (a) an adult does it (b) a child can do it

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