A Million Whys: The Crystal Expedition for Curious Kids

All 150 questions

Tap a question to watch its video and read the answer.

Expedition 1: What a Crystal Is

1. What is a crystal?
2. Why do the atoms in a crystal line up in a pattern?
3. Why do crystals have flat sides and sharp corners?
4. Why does the same crystal always have the same angles?
5. How many different crystal shapes are there?
6. What is symmetry in a crystal?
7. Is glass a crystal?
8. Why do some crystals split along flat lines?
9. What is the difference between a crystal, a mineral, and a rock?
10. How can diamond and pencil graphite both be made of carbon?
11. Why do atoms stack like oranges in a crystal?
12. Are metals made of crystals?
13. Is ice a crystal?
14. Why do some crystals grow as needles and others as cubes?
15. How do scientists look inside a crystal?
16. How did a father and son discover how crystals are built?
17. How small can a crystal be?
18. What is the biggest crystal ever found?
19. Are crystals alive?
20. Is "crystal" glassware real crystal?
21. Do crystals have special powers?
22. What makes some crystals see-through and others milky?
23. What is the smallest repeating piece of a crystal?
24. Why does a salt crystal shatter, but a metal paper clip bends?
25. How can you spot crystals at home?

Expedition 2: How Crystals Grow

26. How does a crystal begin to grow?
27. Why does a tiny seed crystal help a big one grow?
28. Why do slow-growing crystals get bigger than fast-growing ones?
29. What does supersaturated mean?
30. How do crystals appear when salty water dries up?
31. Why do some rocks have a few big crystals sitting in tiny ones?
32. How does a hollow rock fill up with crystals?
33. Why do the crystals in a geode point toward the middle?
34. How can a paper-thin slice of rock show its crystals?
35. How does temperature change which crystals form?
36. Can crystals grow better in space?
37. Do living things make crystals?
38. What is hoarfrost, and why does it make trees look furry white?
39. Why do bismuth crystals look like staircases?
40. How long do crystals take to grow in nature?
41. What makes a growing crystal stop?
42. Why does quartz grow pointy tips?
43. Why do some crystals have stripes or bands?
44. Why do crystals grow in clusters?
45. What is a desert rose?
46. How do scientists grow big, perfect crystals in a lab?
47. Why do crystals grow on a string or twig?
48. Why do taps and glasses get white crusty spots?
49. Can a chipped crystal heal itself?
50. What are the secrets to growing a great crystal?

Expedition 3: Crystals in the Kitchen & Home

51. Why are there so many kinds of sugar if they are all crystals?
52. Why does chocolate have to be tempered to snap?
53. Why does thawed and refrozen ice cream get gritty?
54. Why is fudge smooth but rock candy crunchy?
55. How does maple syrup turn into maple sugar?
56. What are the crunchy bits in aged cheese?
57. Why does salt clump up in the shaker on damp days?
58. Why do some salts look like flakes or pyramids?
59. Why does cold grape juice sometimes have tiny crystals?
60. What is Epsom salt?
61. Is cotton candy made of sugar crystals?
62. What is freezer burn?
63. What is table salt made of, and why does it look like tiny cubes?
64. Why do dried juice spills feel gritty?
65. How does a reusable hand warmer get hot when you click it?
66. Why do white fluffy crystals grow on brick walls?
67. How do factories turn sugar juice into crystals?
68. Why do cooks worry about stray sugar crystals in caramel?
69. Why is butter hard in the fridge but soft on the counter?
70. Why does old hard candy turn cloudy and sticky?
71. Why does old chocolate get a white film?
72. How can you tell salt from sugar without tasting?
73. Why do grains of beach sand flash in the light?
74. What is the crusty white stuff on old batteries?
75. How can you explore crystals safely at your own kitchen table?

Expedition 4: Gems, Minerals & Rock Hounds

76. What makes a mineral a gemstone?
77. What is the Mohs scale?
78. How can you test how hard a mineral is?
79. What is a streak test?
80. How does a mineral's shine help you name it?
81. Why do some rocks feel heavy for their size?
82. Why is a ruby red and a sapphire blue if both are the same mineral?
83. What makes an opal flash rainbow colors?
84. How do gem cutters turn rough stones into gems?
85. What is a lab-grown diamond?
86. What are the crystal patterns inside some meteorites?
87. Why do some minerals glow under a special lamp?
88. How can you tell fool's gold from real gold?
89. What gems and minerals come from Canada?
90. What is a rock hound?
91. What gear does a young rock hound need?
92. Why do rock hounds follow collecting rules?
93. How do you label and keep a rock collection?
94. Where can you see amazing minerals in a museum?
95. How can you tell quartz from calcite?
96. How does a rock tumbler make stones shiny?
97. What everyday things are made from minerals?
98. What is mica, and why does it peel into thin sheets?
99. Do amateur collectors ever discover new minerals?
100. Can a mineral's color fool you?

Expedition 5: Crystals at Work

101. How does a quartz crystal keep a watch on time?
102. What is the piezoelectric effect?
103. How does a click-on barbecue lighter make a spark?
104. How do tiny crystals make buzzers and beeps?
105. Why do computer chips use silicon crystals?
106. How is sand turned into a computer chip?
107. How do liquid crystals make pictures on a screen?
108. How do silicon crystals turn sunshine into electricity?
109. Why does the gap in an LED chip decide its color?
110. What was the first laser made from?
111. Why are watch faces and camera lenses made of sapphire?
112. Why are diamonds on saw blades and drill bits?
113. How did early crystal radios work?
114. Why are jet engine blades grown as one crystal?
115. What is graphene, and why is it special?
116. Why do some crystals flash when invisible rays hit them?
117. Why do glow-in-the-dark stars glow?
118. How does plaster harden?
119. Why does rain slowly eat away a limestone statue?
120. How do blacksmiths change a metal's crystals?
121. How does fluoride toothpaste help teeth?
122. What are zeolites, and what do they do in cat litter?
123. Why do some watches say they have jewels?
124. What is a transistor, and why does a phone need billions?
125. Which gadget at home could not exist without crystals?

Expedition 6: Crystal Labs & Detectives

126. What are the safety rules for growing crystals at home?
127. How can you grow salt crystals in a dish?
128. How can you make rock candy?
129. How can you grow Epsom salt needles overnight?
130. Can you grow crystals on a pipe cleaner shape?
131. How can you make an eggshell geode?
132. Why didn't my crystals grow?
133. How do salt, sugar, and Epsom crystals compare?
134. How can you test what helps crystals grow best?
135. What can a microscope or magnifier show about crystals?
136. How would a detective identify a mystery powder safely?
137. How do mineral detectives use an identification key?
138. How can tiny crystals tell us how old Earth is?
139. How did a scientist use crystals to see the shape of medicines?
140. What can crystals tell us about other planets?
141. Who are the scientists that study crystals?
142. How can you make art with crystals?
143. Are any crystals or minerals unsafe?
144. How do you take care of a crystal collection?
145. What is a quasicrystal?
146. What are scientists still trying to figure out about crystals?
147. How do you make a crystal field guide?
148. How do you keep a crystal journal like a scientist?
149. Could crystals help solve future energy problems?
150. What will you grow and discover next?