Tv Floor Stand Why Did Only Have The Floor Stand & Applaud During The State Of The Union?

Why did only have the floor stand & applaud during the State of the Union? - tv floor stand

During the State of the Union, there were times when only half of the land and applauded when Bush made a statement. Other times, the two sides of the House rose and applauded. Is it because half of the Senate and House of Representatives a? Or is it a side of the Republicans and Democrats on one side? I'm curious, why are only 1 / 2 from the soil and to know, appreciate the times ...... This space can be divided in the middle of the screen.