Strand D2

The Franklin Stove
 
In 1742, Benjamin Franklin designed a wood-burning stove to heat rooms. The front of the stove was open, allowing heat to spread into a room. The back of the stove was closed, but had an air intake that increased air circulation. Fires lit in traditional fireplaces received less oxygen than those lit in Franklin stoves.  
What effect does a lit Franklin stove have on the air molecules in a room?

• decreases their mass
• increases their speed
• decreases their volume
• increases their energy loss

The Rumford fireplace was designed in the 1790’s by Sir Benjamin Thompson.  The fireplace is tall and not very deep.  It was built this was to reflect more heat into a room.   
 
What effect did the Rumford Fireplace have on the air molecules in a room?

• decreases their mass
• increases their speed
• decreases their volume
• increases their energy loss

Mini-split heat exchangers can be used to heat your home.  One part of the mini-split sends warm air into the room.
Where should the warm air enter to best heat the room?

• A - Near the ceiling
• B - Midway up the wall
• C - Near the floor
• D - behind the couch

Mini-split heat exchangers can be used to cool your home.  One part of the mini-split sends cool air into the room.
Where should the cool air enter to best cool the room?

• A - Near the ceiling
• B - Midway up the wall
• C - Near the floor
• D - behind the couch

What color for a roof?

Roofing shingles can be found in a variety of colors.  The color shingle that is chosen for energy efficient homes can change based on where a home is built.
What color roof would an energy efficient home builder likely choose for sunny Florida?

• A black roof as it will absorb the heat from the building.
• A white roof as it will reflect heat away from the building.
• A white roof as it will absorb the heat from the building.
• A black roof as it will reflect heat away from the building.

A Watched Pot

A pot has been heating on a stove.  You grab onto a metal pot handle to move it.  You quickly take your hand away as the handle has become very hot.
How did the handle become hot?

• The stove burner radiated heat to the handle.
• The heat conducted through the pot and to the stove handle.
• Metal is a good insulator and trapped the heat.
• The heat traveled to the handle by convection.

Day at the Beach

You decide to walk along a sandy beach.  You notice the top of the sand is hot.  But the sand underneath is cold. 
 
What is the primary reason the sand underneath is cold?

• The heat rises to the top of the sand by convection.
• Air stops convection by  insulating the top layer of sand.
• Sand is poor at conducting heat to the lower layers.
• The Earth’s spin pulls the heat to the outer layer of sand.