Density is also an important physical property of matter. The concept of density combines what we know about an objects mass and volume. Density reflects how closely packed the particles of matter are. When particles are packed together more tightly, matter is more dense. Differences in density of matter explain many phenomena. It explains why helium balloons rise. It explains why currents such as the Gulf Stream flow through the oceans. It explains why some things float in or sink. You can see this in action by pouring vegetable oil into water. You can see a colorful demonstration in this video.

Question: "What are some things density explains?"

Response: "It explains why some things float in or sink"

A: yes

Joe's parents are farmers and they have a huge farm with cows, chickens, and ducks. Joe loves the farm and all the things he gets to play around and play on. One day, Joe's father told him not to get near a tractor that was sitting in the field. His father was worried that Joe would climb on it and hurt himself. Joe went out to the field and was feeding the horses and cows. When he was done, he saw the tractor his father told him not to get near. He knew that climbing on the tractor wouldn't hurt anything, so he did. He climbed on to the seat and sat there. Then, he pretended he was his father and pretended that he was driving the tractor. Joe's father saw him playing on the tractor and called for him. Joe heard his father calling for him and got off the tractor really fast. When he did that, he fell off and hurt his arm. Joe was in pain and his father came running to check on him and picked him up and sat him on a bench and asked him why he did that. Joe looked at his father and said, "I wanted to be like you." Joe's father gave him a hug and asked him if he wanted to ride with him on the tractor. Joe did and after he got a bandage on his arm, he and his father rode in the field on the tractor.

Question: "Who pretended to be driving the tractor?"

Response: "Joe's father"

A: no

On a busy Friday morning in Manhattan, nine pedestrians suffered bullet or fragment wounds after police unleashed a hail of gunfire at a man wielding a .45 caliber pistol who had just killed a former co-worker. The officers unloaded 16 rounds in the shadow of the Empire State Building at a disgruntled former apparel designer, killing him after he engaged in a gunbattle with police, authorities said. Three passersby sustained direct gunshot wounds, while the remaining six were hit by fragments, according to New York Police Commissioner Ray Kelly. All injuries were caused by police, he said Saturday. One officer shot nine rounds and another shot seven. Police identified the gunman as Jeffrey Johnson, 58, who was apparently laid off from his job as a designer of women's accessories at Hazan Import Co. last year. Johnson, who served in the U.S. Coast Guard in the mid-1970s, had two rounds left in his pistol. It holds eight, Kelly said. Police identified the slain co-worker as Steven Ercolino, 41, who had apparently filed a prior complaint against his assailant, claiming that he thought Johnson would eventually try to kill him. Both men had filed harassment complaints against each other in April 2011, Kelly added. Ercolino was listed as a vice president of sales at Hazan Import Corp., according to his LinkedIn profile. "It's not something that should happen to a loving person like that," said his brother, Paul. "He's going to be so missed by everybody. He was a light of so many lives."

Question: "How many years older was Jeffrey Johnson than Steven Ercolino?"

Response: "Seventeen"

A:
yes