1 self-driving cars of the future It’s 7:30 am A small round car rolls to a stop in front of your home You and your big sister hop into the car You wave to your dad He’s standing in the doorway waving back The car has no driver But it knows where to go You are in a self-driving car Your parents pay for this service A car picks you up every weekday morning It takes you to middle school Then it takes your sister to high school After school it picks you both up and brings you home The car is clean quiet and comfortable There are no controls except an emergency button You can push it in case something goes terribly wrong This will stop the car and call for help But you have never needed to push the button You pass a tree-lined playground Your dad says it used to be a parking lot Now that most people use self-driving car services there are fewer cars and fewer parking lots There is also less pollution Your dad likes that 4
The whole interior of a car could change with self-driving cars With seats facing each other families could talk and interact much more easily When your dad was a kid people drove their own cars most of the time He says it feels strange to ride in cars with no drivers But you’ve been riding in self-driving cars all your life It’s normal for you 5
2 what is steam good for A world of self-driving cars may seem like a wild dream But these cars already exist Engineers are working on making them safe for everyone to use This is just the latest chapter in the story of automobiles That story began more than 300 years ago In the 1600s French scientist Denis Papin experimented with steam He realized he could use steam to move things He put water and a piston in a tube Papin heated the water creating steam The steam moved the piston up and down Other scientists used Papin’s idea to invent the steam engine T The first steam engines were used in coal mines to pump water out of the ground Then in the 1770s British engineers James Watt and Matthew Boulton invented a new kind of steam engine tech tidbit It was called a rotary engine A piston is a cylinder attached to a rod The piston moves up and down This lets the rod turn a machine part
Most trains stopped using steam engines by the 1950s But some steam engines are still used on tourist and heritage lines Rotary engines led to major advancements in transportation These engines could spin wheels and propellers Wheels and propellers could move vehicles People started putting rotary steam engines in trains boats tractors and automobiles 7
