Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 453 · 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 steps is a job for an adult? (a) letting the paper dry (b) plugging in the iron (c) writing the message (d) dipping the cotton bud
2. 2.🧺 Do we need turmeric powder for the secret lemon message? (a) not needed (b) needed
3. 3.🔮 Can the brown writing go back to being invisible? (a) yes, if cooled (b) yes, if shaken (c) no, it stays brown (d) yes, in the dark
4. 4.⚖️ 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
5. 5.🍋 What colour does the lemon writing turn when an adult warms it? (a) brown (b) blue (c) green (d) white
6. 6.🧺 Do we need a balloon for the secret lemon message? (a) needed (b) not needed
7. 7.🧺 Do we need yeast for the secret lemon message? (a) needed (b) not needed
8. 8.⚖️ 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 cotton bud (c) the kind of juice
9. 9.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the kind of juice”? (a) we change it (b) we keep it the same (c) we measure it
10. 10.True or false: a small bowl is needed for the secret lemon message. (a) True (b) False
11. 11.True or false: yeast is not needed for the secret lemon message. (a) True (b) False
12. 12.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a magnet (b) a cotton bud (c) white paper (d) lemon juice
13. 13.🔍 Which is the odd one out? (a) reading the message (b) writing the message (c) dipping the cotton bud (d) plugging in the iron
14. 14.🧺 Which of these is needed for the secret lemon message? (a) a magnet (b) a small bowl (c) a mirror (d) yeast
15. 15.🍋 Which of these steps is a job a child can do? (a) putting the iron away (b) cutting the lemon (c) reading the message (d) ironing the paper
16. 16.🛟 Lemon juice stings cuts and eyes. What should you do after the experiment? (a) skip washing (b) lick your fingers (c) wash your hands (d) rub your eyes
17. 17.🛟 Who should use the hot iron in the secret message experiment? (a) whoever is fastest (b) any child (c) only an adult (d) the youngest child
18. 18.True or false: plugging in the iron is a job a child can do. (a) True (b) False
19. 19.🧺 Do we need an adult with an iron for the secret lemon message? (a) not needed (b) needed
20. 20.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the iron setting”? (a) we keep it the same (b) we measure it (c) we change it
21. 21.⚖️ 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
22. 22.🍋 Secret message: who does this step — plugging in the iron? (a) an adult does it (b) a child can do it
23. 23.🍋 Secret message: who does this step — dipping the cotton bud? (a) a child can do it (b) an adult does it
24. 24.🛟 Why must children keep their fingers away from the iron? (a) it is cold (b) it is sticky (c) it can burn skin (d) it is magnetic
25. 25.🧺 Do we need white paper for the secret lemon message? (a) not needed (b) needed
26. 26.True or false: writing the message is a job for an adult. (a) True (b) False
27. 27.🧺 Do we need a small bowl for the secret lemon message? (a) not needed (b) needed
28. 28.⚖️ 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
29. 29.🧺 Which of these is not needed for the secret lemon message? (a) a small bowl (b) white paper (c) a cotton bud (d) a mirror
30. 30.🍋 Secret message: who does this step — reading the message? (a) an adult does it (b) a child can do it
31. 31.🔮 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
32. 32.🧺 Which of these is needed for the secret lemon message? (a) a balloon (b) lemon juice (c) a mirror (d) yeast
33. 33.🔍 Which is the odd one out? (a) ironing the paper (b) letting the paper dry (c) cutting the lemon (d) putting the iron away
34. 34.True or false: a balloon is not needed for the secret lemon message. (a) True (b) False
35. 35.🧺 Which of these is needed for the secret lemon message? (a) yeast (b) a magnet (c) a mirror (d) a cotton bud
36. 36.🍋 Secret message: who does this step — ironing the paper? (a) a child can do it (b) an adult does it
37. 37.🍋 Secret message: who does this step — writing the message? (a) an adult does it (b) a child can do it
38. 38.🍋 Which of these steps is a job a child can do? (a) cutting the lemon (b) plugging in the iron (c) ironing the paper (d) letting the paper dry
39. 39.True or false: white paper is needed for the secret lemon message. (a) True (b) False
40. 40.True or false: letting the paper dry is a job a child can do. (a) False (b) True

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