SANFORD, Fla. -

When defense attorney Mark O'Mara spoke with potential jurors last week he walked them through several legal terms. Many of you wanted to know a little bit more about them so I asked University of Miami law school professor Tamara Lave to offer clarification. Lave was a deputy public defender for a decade in San Diego before getting her PhD and becoming a law professor. "That means that I have chosen lots of juries in my time!," she explained.

"Here are my responses to your questions:

1. Presumption of innocence means that the defendant is presumed to be innocent. In other words, the jurors must disregard the fact that he has been arrested and is sitting in court as a charged suspect. Instead they must see him as innocent, which means that if they had to render a verdict right now, their verdict would have to be not guilty. It is the prosecutor's job to convince them beyond a reasonable doubt that the defendant is guilty, and unless and until the prosecutor does that, the jurors must acquit. One way of thinking about the presumption of innocence is like a football game, but instead of the defendant and the prosecutor starting at the 50 yard line, the game begins closer to the one yard line and the prosecutor has to drive the ball all the way down the field to the other end zone to score.

2. Beyond a reasonable doubt is the highest burden of proof in our trial system. It means that the jurors may not convict a defendant unless and until the prosecutor has convinced them to such a degree that they have no reasonable question as to his guilt. This doesn't mean that the jurors can't have any doubt because everything in life is open to some possible or imaginary doubt; it means that they must have an abiding conviction of the truth of the charges. As a result, jurors should end up acquitting someone even though they believe he probably did it or even that it's likely that he did it. Beyond a reasonable doubt demands more.

3. Beyond a reasonable doubt should be contrasted with presumption of the evidence, which is the burden of the moving party in a civil action. Presumption of the evidence means that the moving party must prove his or her case by a 51% burden. They just need to tip the scales slightly to prevail.

4. Before explaining what second degree murder means in Florida, it is helpful to understand why there are degrees of homicide. Distinguishing between first degree murder, second degree murder, and manslaughter is a way of differentiating between the culpability of defendants. The legislature believes that planning someone's death reflects a more dangerous and responsible killer than one who kills without planning it or it one who kills accidentally. Accordingly, there is also a difference in possible punishment. Defendants convicted of first degree murder can face the death penalty, but those convicted of second degree murder cannot. Similarly, defendants convicted of second degree murder face life in prison but those convicted of some level of manslaughter do not.

With that in mind Second degree murder in Florida is defined as follows: The unlawful killing of a human being, when perpetrated by any act imminently dangerous to another and evincing a depraved mind regardless of human life, although without any premeditated design to effect the death of any particular individual, is murder in the second degree and constitutes a felony of the first degree, punishable by imprisonment for a term of years not exceeding life or as provided in s. 775.082, s. 775.083, or s. 775.084

This is just a fancy way of saying that George Zimmerman is accused of killing Trayvon Martin unlawfully and without planning it in advance. The fact that the act must be imminently dangerous means that Zimmerman must have been doing something which was immediately dangerous instead of just possibly dangerous. Saying that he needs to evince a depraved heart is a way of saying that he acted without sufficient regard for human life. This is sometimes stated as a "hardness of heart." Shooting a gun into a crowded movie theater is one example of an act that shows a depraved heart.

5. The defense is spending a lot of time explaining these terms to the jurors for a few reasons. First, the Defense wants to educate the jurors and make sure that they are willing to follow the law. Sometimes prospective jurors are reluctant to admit that they are unwilling or unable to do so. Asking the jurors lots of questions makes it easier to find out how they really feel. The Defendant has a constitutional right to a fair and impartial jury which means that if the judge believes that there are jurors who are biased against him, the judge must strike those prospective jurors from the jury. Even if the judge does not dismiss those jurors for cause, the defendant has the right to strike several of them on his own using what is called peremptory challenges.

Finally both lawyers want to make a good impression on the jurors so that they are more likely to win their case. The voir dire process is the only opportunity that they have to interact directly with jurors and ask them questions. Thus they want to make the most of it.