The Great Expedition Series, Book 3

A Million Whys: The Built Expedition for Curious Kids

By Crafty Clover. Published by Million Whys Press.

Why planes fly, why bridges stand, why lights turn on, and why a zipper zips. 150 questions about machines and things people build.

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All 150 questions

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

Questions 1 to 25

1. Why Do Bikes Stay Up When You Ride?
2. Why Do Airplanes Stay in the Sky?
3. Why Do Boats Float?
4. Why Do Wheels Beat Dragging?
5. Why Do Paper Airplanes Fly?
6. Why Do Trains Need Tracks?
7. Why Do Helicopters Hover?
8. Why Do Cars Need Brakes?
9. Why Is a Ship Pointed in Front?
10. Why Do Hot Air Balloons Go Up?
11. Why Do Tires Have Treads?
12. Why Do Planes Have Flaps?
13. Why Do Submarines Sink and Rise?
14. Why Do Bikes Have Gears?
15. Why Do Rockets Need Fire?
16. Why Do Cars Have Seatbelts?
17. Why Do Airplanes Have Propellers?
18. Why Do Sailboats Need Wind?
19. Why Do Skateboards Roll?
20. Why Do Parachutes Work?
21. Why Do Trucks Have So Many Wheels?
22. Why Do Gliders Fly with No Engine?
23. Why Do Cars Have Headlights?
24. Why Do Tunnels Go Through Mountains?
25. Why Do Boats Have Rudders?

Questions 26 to 50

26. Why Do Lights Turn on with a Switch?
27. Why Do Batteries Die?
28. Why Is Fire Hot?
29. Why Do Magnets Stick?
30. Why Do Solar Panels Work?
31. Why Do We See Lightning Before Thunder?
32. Why Does Static Make Hair Stick Up?
33. Why Do Phones Need Charging?
34. Why Do Light Bulbs Get Warm?
35. Why Does Ice Melt?
36. Why Do Fans Cool Us?
37. Why Is a Toaster Hot?
38. Why Does a Kettle Whistle?
39. Why Do Fireworks Have Colors?
40. Why Does a Compass Point North?
41. Why Does a Microwave Heat Food?
42. Why Do LED Lights Use Less Power?
43. Why Does Rubbing Hands Make Heat?
44. Why Does Steam Rise?
45. Why Do Plugs Have Three Prongs?
46. Why Do Power Lines Hum?
47. Why Does a Fridge Stay Cold?
48. Why Do Shadows Happen?
49. Why Is the Sun So Bright?
50. Why Does a Candle Melt?

Questions 51 to 75

51. Why Do Buildings Have Foundations?
52. Why Do Bridges Have Arches?
53. Why Do Skyscrapers Sway?
54. Why Is Concrete So Strong?
55. Why Do Houses Have Sloped Roofs?
56. Why Do Windows Have Glass?
57. Why Do Doors Have Hinges?
58. Why Do Stairs Have Railings?
59. Why Do Chimneys Go Up?
60. Why Do Buildings Have Elevators?
61. Why Do Suspension Bridges Use Cables?
62. Why Do Tunnels Have Lining?
63. Why Do Walls Use Bricks?
64. Why Do Roofs Have Gutters?
65. Why Do Buildings Have Insulation?
66. Why Can Cranes Lift So Much?
67. Why Do Dams Hold Back Water?
68. Why Do Lighthouses Flash?
69. Why Do Stadiums Have Huge Roofs?
70. Why Do Towers Stay Standing?
71. Why Do Floors Have Beams?
72. Why Do Cities Have Sewers?
73. Why Do Sidewalks Crack?
74. Why Do Pyramids Last So Long?
75. Why Do Buildings Need Doors That Open?

Questions 76 to 100

76. Why Do Phones Ring?
77. Why Does Email Arrive So Fast?
78. Why Do Radios Play Music From Far Away?
79. Why Do Cameras Take Pictures?
80. Why Do Clocks Keep Time?
81. Why Do Computers Need Programs?
82. Why Does Wi-Fi Have No Wires?
83. Why Do Barcodes Beep at the Store?
84. Why Do TVs Show Moving Pictures?
85. Why Do Speakers Make Sound?
86. Why Do Keyboards Have Letters?
87. Why Do Printers Put Ink on Paper?
88. Why Do Satellites Help Phones?
89. Why Does GPS Know Where You Are?
90. Why Do Traffic Lights Change?
91. Why Do Doorbells Ring?
92. Why Did Morse Code Use Dots and Dashes?
93. Why Do QR Codes Hold So Much?
94. Why Do Microphones Pick Up Voices?
95. Why Do Headphones Work?
96. Why Do Video Calls Show Faces Far Away?
97. Why Do Robots Follow Instructions?
98. Why Do Remote Controls Work?
99. Why Do Smoke Alarms Beep?
100. Why Do Passwords Exist?

Questions 101 to 125

101. Why Does a Ball Bounce?
102. Why Can You Ride a Bike Without Falling?
103. Why Do Swim Goggles Keep Water Out?
104. Why Does a Bat Have a Sweet Spot?
105. Why Is a Soccer Ball Made of Panels?
106. Why Does a Whistle Get So Loud?
107. Why Do Drums Boom?
108. Why Does Tightening a Guitar String Raise the Pitch?
109. Why Does an Echo Come Back?
110. Why Do Ice Skates Glide?
111. Why Does a Frisbee Fly?
112. Why Does a Swing Go Higher If You Pump?
113. Why Do Helmets Have Foam?
114. Why Does a Yo-Yo Come Back?
115. Why Do Bubbles Shimmer Then Pop?
116. Why Does a Kite Need Wind?
117. Why Do Sneakers Grip the Ground?
118. Why Does a Jump Rope Need a Rhythm?
119. Why Do Bowling Balls Have Finger Holes?
120. Why Does a Basketball Have Black Lines?
121. Why Do Referees Use Whistles?
122. Why Does a Trombone Note Drop When the Slide Moves Out?
123. Why Do Marching Bands Stay in Step?
124. Why Does a Playground Slide Feel Fast?
125. Why Do Team Jerseys Have Numbers?

Questions 126 to 150

126. Why Does a Hammer Have a Heavy Head?
127. Why Is a Screwdriver Shaped Like That?
128. Why Do Scissors Have Two Blades?
129. Why Does Glue Stick?
130. Why Does Tape Have Two Sides That Feel Different?
131. Why Do Nails Have Points and Screws Have Threads?
132. Why Does Sandpaper Scratch?
133. Why Does a Measuring Tape Roll Back Up?
134. Why Do Magnets Pick Up Only Some Metals?
135. Why Does a Level Have a Bubble?
136. Why Do Factories Use Conveyor Belts?
137. Why Do Bakers Weigh Instead of Just Scoop?
138. Why Does a Sewing Machine Make a Lockstitch?
139. Why Do 3D Printers Print in Layers?
140. Why Do Welders Wear a Dark Mask?
141. Why Does a Potter's Wheel Spin?
142. Why Do Carpenters Use Squares?
143. Why Does Paint Dry?
144. Why Do Zippers Zip?
145. Why Does a Vacuum Cleaner Suck?
146. Why Do Firefighters Use Axes and Hoses?
147. Why Do Doctors Wear Gloves?
148. Why Does a Cash Register Beep?
149. Why Do Libraries Use the Same Number Codes?
150. Why Do Makers Prototype First?