The Great Expedition Series, Book 15

A Million Whys: The Robot Expedition for Curious Kids

By Crafty Clover. Published by Million Whys Press.

Why Do We Call a Machine a Robot? Why Does a Motor Spin When You Connect a Battery? Why Do Most Small Drones Have Four Rotors? This book answers 150 questions like these, one question per page, each with a short video answer. Six expeditions: Robot Basics, Sensors That Notice, Motors, Joints & Wheels, Helper Robots at Work, Drones, Rovers & Explorers, and Robot Brains & Build-It Ideas.

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All 150 questions

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

Expedition 1: Robot Basics

1. Why Do We Call a Machine a Robot?
2. Why Isn't a Remote-Control Car a Robot?
3. Why Is a Toaster Not a Robot but a Robot Vacuum Is?
4. Where Does the Word Robot Come From?
5. Why Do Many Robots Look Nothing Like People?
6. Why Do Engineers Sometimes Build Robots in Human Shapes?
7. Why Does Every Robot Need a Body, a Brain, and a Power Source?
8. How Does a Robot Get the Energy to Move?
9. What Does a Robot's Brain Actually Do?
10. Why Do Robots Keep Repeating Sense, Think, Act?
11. Why Can a Robot Do the Same Job Thousands of Times Without Getting Tired?
12. Why Are Some Easy Things for People Really Hard for Robots?
13. Why Does a Robot's Weight Matter So Much to Designers?
14. Why Isn't a Laptop a Robot?
15. Why Was the First Factory Robot Just an Arm?
16. Why Aren't Real Robots as Clever as Robots in Movies?
17. Why Do Engineers Draw a Robot Before They Build It?
18. Why Do Engineers Test a Robot Again and Again?
19. Why Do Robots Have Emergency Stop Buttons?
20. Why Are Some Big Robots Kept Behind Safety Fences?
21. Why Can Some Robots Work Safely Next to People?
22. What Does It Mean When a Robot Is Autonomous?
23. Why Do Some Robots Need a Person to Steer Them From Far Away?
24. Why Do Engineers Send Robots to Places That Are Too Hot, Too Deep, or Too Far for People?
25. How Small Can a Robot Get, and How Big?

Expedition 2: Sensors That Notice

26. What Is a Sensor, and Why Do Robots Need Them?
27. How Does a Bump Sensor Tell a Robot It Has Hit a Wall?
28. How Does a Robot’s Ultrasonic Sensor Find How Far Away a Wall Is?
29. How Does a Robot Use a Laser Beam to Map the Space Around It?
30. Why Can a Robot Follow a Black Line on the Floor?
31. How Does a Robot Know Which Way Is Up?
32. How Does a Robot Know How Far It Has Driven?
33. Why Do Some Robots Have Touch-Sensitive Skin?
34. How Can a Robot Use a Camera to Find a Ball?
35. Why Do Robots Sometimes Get Confused by Bright Sunlight?
36. Why Do Robots Use Many Sensors Instead of Just One?
37. How Does a Robot Sense Heat?
38. Why Can a Robot Turn Toward a Clap?
39. Why Does a Robot with a Light Sensor Follow a Flashlight?
40. Why Do Robots Use GPS Outdoors but Not Inside?
41. Why Doesn't a Robot Vacuum Fall Down the Stairs?
42. Why Do Robot Sensors Sometimes Get Things Wrong?
43. Why Do Automatic Doors Open as You Walk Up?
44. How Does a Robot Arm Know When It Has Reached the End of Its Swing?
45. How Can a Magnet Tell a Robot Where Its Parts Are?
46. How Does a Robot Hand Know How Hard to Squeeze?
47. How Does a Light Curtain Stop a Factory Robot When Someone Gets Close?
48. How Can a Robot Sort Red Blocks From Blue Ones?
49. Why Do Some Robots Carry Gas Sensors?
50. How Does a Robot Find Its Charging Station?

Expedition 3: Motors, Joints & Wheels

51. Why Does a Motor Spin When You Connect a Battery?
52. Why Do Robot Motors Have Tiny Gearboxes?
53. What Is a Servo Motor?
54. Why Can a Stepper Motor Move in Tiny, Exact Steps?
55. Why Do Robots Use Wheels More Often than Legs?
56. Why Do Many Walking Robots Have Four Legs?
57. Why Is Balancing on Two Legs Such a Challenge for a Robot?
58. How Does a Robot Turn by Spinning Its Wheels at Different Speeds?
59. Why Do Some Robots Have Tank Treads?
60. Why Do Some Robots Roll on Balls or Special Sideways Wheels?
61. Why Do Robot Arms Have Joints Like a Shoulder and an Elbow?
62. Why Does a Robot Arm Need About Six Joints to Reach Anywhere?
63. How Does a Robot Gripper Pick Up Things?
64. Why Do Some Robot Hands Use Suction Cups?
65. Why Are Some Robots Soft and Squishy?
66. Why Does a Long Robot Arm Lift Less than a Short One?
67. Why Do Robots Use Belts and Pulleys?
68. Why Do Robot Motors Get Warm?
69. How Does a Robot Arm Know Exactly Where Its Hand Is?
70. Why Does a Robot Sometimes Overshoot Its Stop and Wobble Back?
71. How Can a Robot Jump or Hop?
72. Why Do Some Robots Wriggle Like Snakes?
73. How Can a Robot Balance on Just Two Wheels?
74. Why Do Some Strong Robots Push with Air or Liquid?
75. Why Do Robot Builders Choose Lightweight Materials?

Expedition 4: Helper Robots at Work

76. How Does a Robot Vacuum Map a Room?
77. Why Do Robot Vacuums Get Stuck on Socks and Cords?
78. Why Does a Robot Lawn Mower Stay Inside the Yard?
79. How Do Pool-Cleaning Robots Clean Underwater?
80. How Do Window-Cleaning Robots Stick to Glass?
81. Why Do Warehouses Use Flat Robots That Carry Shelves?
82. How Do Factory Robots Paint Cars So Evenly?
83. How Can a Robot Pick a Strawberry Without Squishing It?
84. Why Do Farm Robots Drive Along the Crop Rows?
85. How Do Robots Sort Recycling?
86. What Is Canadarm2, and What Does It Do?
87. How Do Small Robots Crawl Through Pipes to Find Leaks?
88. Why Do Robots Climb Wind Turbines and Tall Towers?
89. Why Do Delivery Robots Roll Along Sidewalks?
90. How Can Small Robots Help Search a Collapsed Building?
91. How Do Robots Scrub the Bottoms of Big Ships?
92. How Can a Robot Build a Brick Wall?
93. Why Do Robots in Science Labs Move Tiny Drops of Liquid?
94. Why Do Greenhouse Robots Check Plants One by One?
95. Why Can Some Robots Work in Total Darkness?
96. How Do Warehouse Robots Avoid Bumping Into Each Other?
97. How Do Robots Pack Cookies Without Breaking Them?
98. Why Do Robots Clean Solar Panels?
99. How Do Robots Sort Parcels So Fast?
100. Why Can't One Robot Cook, Clean, and Fold Laundry Yet?

Expedition 5: Drones, Rovers & Explorers

101. Why Do Most Small Drones Have Four Rotors?
102. How Does a Drone Stay Level in the Air?
103. Why Do Two of a Drone's Propellers Spin One Way and Two the Other?
104. Why Does a Drone Tilt to Fly Forward?
105. Why Can't Most Drones Fly for Very Long?
106. Why Do Some Drones Have Little Cages Around the Propellers?
107. Why Must Drones Stay Away From Airports and Crowds?
108. How Can a Drone Help a Farmer Check a Big Field?
109. How Do Drones Make Maps and 3D Models?
110. Why Can Drone Light Shows Paint Pictures in the Night Sky?
111. How Do Delivery Drones Carry Packages?
112. How Do Scientists Use Drones to Study Tall Trees and Forest Canopies?
113. Why Can a Drone Hover but an Airplane Can't?
114. Why Is a Rover Not Just a Small Car?
115. How Does a Rover Keep Its Wheels on the Ground Over Bumpy Rocks?
116. Why Does a Rover Only Drive a Little Bit at a Time?
117. Why Do Rovers Carry Rock-Zapping Lasers and Drills?
118. How Do Rovers Get Power on Other Worlds?
119. Why Do Rovers Have Cameras on Tall Masts?
120. Why Do We Send Rovers to the Moon?
121. How Do Underwater Robots Take Pictures in the Dark Deep?
122. Why Do Some Underwater Robots Glide by Changing Their Weight?
123. How Do Robots Explore Caves That Are Too Narrow for People?
124. Why Do Engineers Copy Animals When They Build Robots?
125. Why Do Swarms of Tiny Robots Work Together Like Ants?

Expedition 6: Robot Brains & Build-It Ideas

126. How Does a Robot Decide What to Do Next?
127. Why Must Instructions for a Robot Be So Exact?
128. Why Do Robot Instructions Use If-Then Rules?
129. Why Does a Robot Check, Act, and Check Again?
130. Why Can a Robot Get Out of a Maze by Always Turning Left?
131. Why Do Robots Need Maps or Landmarks?
132. Why Do Robots Take Tiny Measurements Many Times a Second?
133. Why Can a Robot Fail Even When It Follows Every Step Perfectly?
134. How Does a Robot Know When Its Job Is Finished?
135. What Does a Robot Do When Something Blocks Its Path?
136. Why Do Some Robots Remember Where They Have Been?
137. How Can a Robot Arm Learn by Trying Again and Again?
138. Why Do Builders Test Robot Ideas with Cardboard First?
139. What Happens at a Kids' Robot-Building Contest?
140. How Can a Game of Robot Says with a Friend Show How a Robot Reads Steps?
141. How Can You Build a Cardboard Robot Arm That Really Grips?
142. Why Do Robot Builders Wear Safety Glasses?
143. Why Do Robot Batteries Need Extra Care?
144. How Do the Parts of a Robot Send Messages to Each Other?
145. Why Are the Best Robots Often the Simplest?
146. Why Do Some Robots Wait for a Signal Before They Start?
147. Why Do Engineers Try to Build Robots From Parts That Can Be Reused or Recycled?
148. How Do You Keep a Robot Working for Years?
149. Why Do Inventors Start with a Problem Before They Design a Robot?
150. What Could Robots Help Scientists Explore Next?