Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 267 · 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 — plugging in the iron? (a) an adult does it (b) a child can do it
2. 2.🧺 Do we need a magnet for the secret lemon message? (a) needed (b) not needed
3. 3.🧺 Which of these is not needed for the secret lemon message? (a) a cotton bud (b) lemon juice (c) white paper (d) a balloon
4. 4.🧺 Do we need a balloon for the secret lemon message? (a) needed (b) not needed
5. 5.🛟 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
6. 6.⚖️ 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
7. 7.🔍 Which is the odd one out? (a) reading the message (b) writing the message (c) cutting the lemon (d) dipping the cotton bud
8. 8.🔮 Can the brown writing go back to being invisible? (a) yes, if shaken (b) no, it stays brown (c) yes, in the dark (d) yes, if cooled
9. 9.🍋 Secret message: who does this step — cutting the lemon? (a) an adult does it (b) a child can do it
10. 10.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) skip washing (b) wash your hands (c) lick your fingers (d) rub your eyes
11. 11.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) lemon juice (b) yeast (c) white paper (d) an adult with an iron
12. 12.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is kept the same? (a) the same paper (b) how dark the writing is (c) the kind of juice
13. 13.🔮 Predict: you write with plain water instead of lemon juice. What appears after ironing? (a) dark brown words (b) a rainbow (c) almost nothing (d) blue words
14. 14.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the same cotton bud is the one thing we change. (a) True (b) False
15. 15.🍋 What colour does the lemon writing turn when an adult warms it? (a) white (b) blue (c) green (d) brown
16. 16.⚖️ 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 iron setting
17. 17.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) lemon juice (b) a mirror (c) a cotton bud (d) a small bowl
18. 18.🍋 Secret message: who does this step — ironing the paper? (a) a child can do it (b) an adult does it
19. 19.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) an adult with an iron (b) a small bowl (c) a cotton bud (d) a magnet
20. 20.🍋 Secret message: who does this step — writing the message? (a) a child can do it (b) an adult does it
21. 21.🛟 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
22. 22.True or false: reading the message is a job a child can do. (a) True (b) False
23. 23.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is what we measure? (a) how dark the writing is (b) the kind of juice (c) the same cotton bud (d) the ironing time
24. 24.🧺 Do we need white paper for the secret lemon message? (a) needed (b) not needed
25. 25.⚖️ 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
26. 26.True or false: an adult with an iron is needed for the secret lemon message. (a) True (b) False
27. 27.🧺 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) a cotton bud
28. 28.True or false: dipping the cotton bud is a job for an adult. (a) True (b) False
29. 29.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is the one thing we change? (a) how dark the writing is (b) the iron setting (c) the ironing time (d) the kind of juice
30. 30.🧺 Do we need lemon juice for the secret lemon message? (a) needed (b) not needed
31. 31.🧺 Which of these is not needed for the secret lemon message? (a) lemon juice (b) white paper (c) turmeric powder (d) a small bowl
32. 32.True or false: cutting the lemon is a job a child can do. (a) False (b) True
33. 33.True or false: a magnet is not needed for the secret lemon message. (a) False (b) True
34. 34.🔍 Which is the odd one out? (a) letting the paper dry (b) dipping the cotton bud (c) putting the iron away (d) reading the message
35. 35.True or false: ironing the paper is a job a child can do. (a) False (b) True
36. 36.🔍 Which is the odd one out? (a) putting the iron away (b) plugging in the iron (c) dipping the cotton bud (d) ironing the paper
37. 37.True or false: cutting the lemon is a job for an adult. (a) False (b) True
38. 38.True or false: letting the paper dry is a job for an adult. (a) False (b) True
39. 39.🍋 Which of these steps is a job a child can do? (a) letting the paper dry (b) cutting the lemon (c) putting the iron away (d) plugging in the iron
40. 40.🍋 Secret message: who does this step — putting the iron away? (a) an adult does it (b) a child can do it

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