The burglar alarm

Guess the invention: "I was invented by an ancient Indian mathematician. I add value to numbers: 9 becomes 90, then 900." Yes, zero! Imagine the world without inventions: no electricity, no phones, no internet. Inventors need curiosity, creativity and courage to take risks. Unit 3 opens with a story about a boy who has plenty of all three!

The story, by Anita Rau Badami, opens with a roar from the front door: "Who put that water bag here?"

"Your burglar alarm," the narrator hisses to her brother Anand, who is getting ready to vanish. Ma rushes in to see what the racket (loud noise) is about, and finds Papa sopping wet and scowling (frowning angrily). "Where's that boy? I'm sure he rigged this up!" Anand disappears until after dinner, when Papa has cooled down.

The narrator introduces herself: "I am Anita, fourteen. My brother Anand, a year younger, caused all that hoo-ha." It isn't the first time he's annoyed Papa or frightened someone half to death.

"The trouble with him is that he thinks he's a scientist." He loves tinkering (fiddling) with gadgets, tools, dynamos and planks of wood, and he keeps making inventions that never work the way they should.

This one had a reason: there had been a rush of thefts in the colony. As soon as Papa left for the office and Ma for the market, Anand got to work. Anita had to help, though she'd rather finish her novel. "If you get a shelling (a scolding), don't bring me in!"

"Nothing will go wrong this time. See the blueprint!" (Anand loves that word; it makes him feel professional.) "When the door opens, the alarm goes off with a clanging sound, then this water bag falls on the thief's head. Then we call the police. Simple!"

"But how does the alarm know it's a burglar?" "I've thought of that," Anand said grandly. "A thief opens the door stealthily (quietly). So the alarm works only when the door is opened gently." Anita was sceptical (doubtful), and she was right. Who always opens the door gently? Papa!