Can anyone define thermostat and list electrical appliances that have a thermostat?

A thermostat is a switch that operates itself when the temperature
goes above or below a temperature that the user can set.

-- Before you go to bed, you set the thermostat for 65° .
If the temperature in the house goes below 65° during the night,
the thermostat turns on the furnace, and keeps it running until
the house warms up to 65°.  Then it shuts the furnace off.

-- After breakfast, you set the thermostat for 75°.
If the temperature in the house goes above 75°, during the day, 
the thermostat turns on the air conditioner, and keeps it running until
the house cools down to 75°.  Then it shuts the air conditioner off.  

-- On Sunday morning, you put the slow cooker on the kitchen counter,
and you throw in a big roast, a sliced onion, some baby carrots, some
sliced potatoes, some vegetable stock, salt, pepper, garlic, chili powder,
and tomato paste.  Then you put the cover on, turn the power on, and
set the slow cooker to "LOW".  The heater in the slow cooker turns on.
  Whenever the temperature in the crock gets higher than 160°, the
thermostat in the slow cooker turns off the heater, and keeps it off
until the crock cools down to 160°.  Then the thermostat turns the
heater on again.
  By dinner time, you have a hot, juicy, scrumptious pot roast, ready
to eat.  It's not too hot, not too cold, not too tough, not dried out, and
it melts in your mouth.
You're still thinking about it when you go to bed, and your mom gives you
a slice to take to school for your lunch on Monday.