Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 102 · 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.True or false: cutting the lemon is a job a child can do. (a) True (b) False
2. 2.🧺 Which of these is needed for the secret lemon message? (a) yeast (b) turmeric powder (c) a battery cell (d) white paper
3. 3.🍋 Why can’t you see the lemon writing once it dries? (a) it turned into air (b) the ink is magnetic (c) dry juice is see-through (d) the paper ate it
4. 4.🍋 Which of these steps is a job a child can do? (a) putting the iron away (b) ironing the paper (c) dipping the cotton bud (d) cutting the lemon
5. 5.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the iron setting is kept the same. (a) False (b) True
6. 6.🍋 Secret message: who does this step — letting the paper dry? (a) a child can do it (b) an adult does it
7. 7.🍋 What colour does the lemon writing turn when an adult warms it? (a) blue (b) brown (c) green (d) white
8. 8.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) white paper (b) yeast (c) a small bowl (d) lemon juice
9. 9.🔮 Can the brown writing go back to being invisible? (a) yes, if cooled (b) yes, in the dark (c) yes, if shaken (d) no, it stays brown
10. 10.🍋 Secret message: who does this step — writing the message? (a) a child can do it (b) an adult does it
11. 11.🔮 Predict: the adult irons for only one second. What happens? (a) the paper floats (b) writing turns green (c) it gets darker (d) writing stays faint
12. 12.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is kept the same? (a) the ironing time (b) how dark the writing is (c) the kind of juice
13. 13.🛟 Who should use the hot iron in the secret message experiment? (a) only an adult (b) whoever is fastest (c) the youngest child (d) any child
14. 14.🧺 Which of these is needed for the secret lemon message? (a) lemon juice (b) turmeric powder (c) a magnet (d) a balloon
15. 15.🛟 Why must children keep their fingers away from the iron? (a) it can burn skin (b) it is sticky (c) it is magnetic (d) it is cold
16. 16.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the same paper”? (a) we change it (b) we measure it (c) we keep it the same
17. 17.🧺 Do we need turmeric powder for the secret lemon message? (a) not needed (b) needed
18. 18.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the same paper is kept the same. (a) True (b) False
19. 19.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the ironing time”? (a) we measure it (b) we change it (c) we keep it the same
20. 20.🧺 Do we need a balloon for the secret lemon message? (a) needed (b) not needed
21. 21.🔍 Which is the odd one out? (a) plugging in the iron (b) writing the message (c) dipping the cotton bud (d) letting the paper dry
22. 22.🍋 Secret message: who does this step — reading the message? (a) an adult does it (b) a child can do it
23. 23.⚖️ 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
24. 24.🍋 Which of these steps is a job for an adult? (a) reading the message (b) dipping the cotton bud (c) plugging in the iron (d) writing the message
25. 25.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) lemon juice (b) a cotton bud (c) a magnet (d) an adult with an iron
26. 26.🔍 Which is the odd one out? (a) cutting the lemon (b) plugging in the iron (c) ironing the paper (d) reading the message
27. 27.🧺 Do we need a mirror for the secret lemon message? (a) not needed (b) needed
28. 28.True or false: letting the paper dry is a job a child can do. (a) False (b) True
29. 29.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) an adult with an iron (b) a battery cell (c) a cotton bud (d) a small bowl
30. 30.True or false: turmeric powder is not needed for the secret lemon message. (a) True (b) False
31. 31.🍋 Secret message: who does this step — cutting the lemon? (a) an adult does it (b) a child can do it
32. 32.⚖️ 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 same paper (c) how dark the writing is (d) the kind of juice
33. 33.True or false: putting the iron away is a job for an adult. (a) False (b) True
34. 34.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) skip washing (b) rub your eyes (c) wash your hands (d) lick your fingers
35. 35.🧺 Which of these is not needed for the secret lemon message? (a) an adult with an iron (b) a cotton bud (c) a magnet (d) lemon juice
36. 36.True or false: an adult with an iron is needed for the secret lemon message. (a) False (b) True
37. 37.⚖️ 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
38. 38.🧺 Do we need yeast for the secret lemon message? (a) needed (b) not needed
39. 39.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is the one thing we change? (a) the iron setting (b) the same cotton bud (c) the same paper (d) the kind of juice
40. 40.🍋 Secret message: who does this step — plugging in the iron? (a) an adult does it (b) a child can do it

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