Week 3 Inventions

I learned about four inventions this week: the pencil, the stethoscope, the tunneling shield, and paved roads.

The pencil is one of the most helpful and simplest inventions.  I learned that it is actually graphite, not lead, in the pencils.  The pencil is made by putting graphite in a wooden case.  It is used by rubbing it across a surface.  The pencil has really helped make life easier because without the pencil it would be really hard to sketch.  If one made a mistake in writing it could be erased, unlike ink.

The stethoscope is a long tube that runs up to one’s ears.  Doctors use the stethoscope to listen to their patients heart beat.  A man named Rene Laennec invented the stethoscope.  He was treating a woman but he was too embarrassed to put his ear up to her heart.  Then he remembered seeing kids talking into one end of a tube and putting their ear up to the other and it would amplify the sound.  So he rolled up a piece of paper and put it up to her heart, and he could hear it really well.  Because doctors can hear our hearts better, they can figure out what is wrong faster.  That is why the stethoscope changed history. 

The tunneling shield is a machine that helps dig tunnels underground without the tunnel collapsing.  It works by holding the ground up while the workers build the tunnel, then the tunneling shield moves forward and the workers build some more.  It impacted history because tunnels could be built underground so things like subways could run underground out of the way of cars.

Paved roads are very helpful.  Before roads were made of dirt. In Rome they were made of stone, but it took a lot of work to do that.  So gravel was used, but dust was still kicked up and the roads did not last very long.  Then someone accidently spilled tar on the road and tried to fix it by covering it with gravel. It stuck really well, so they started using that.  It changed life because it is easier to drive on the roads because they are smooth.

So the pencil, the stethoscope, the tunneling shield, and paved roads all have helped make life easier.