We all learned in high school that the boiling point of water is somewhere near 212 degrees Fahrenheit.
Want to watch a college football fan's blood boil? Go 4-8 or 5-7 and lose to your school's archrival for the seventh time in eight seasons.
Or take control of one of the sport's traditional powers and lose to, ahem, Toledo at home.
Which coaches enter the 2009 season on the hot seat? There are nearly 20 of them, although some of their backsides are warmer than others.
We break them down in three categories: hot, warm and lukewarm.
1. Charlie Weis, Notre Dame
Weis is only 29-21 in four seasons at Notre Dame, a winning percentage that is slightly worse than those of predecessors Bob Davie and Tyrone Willingham, neither of whom lasted longer than five seasons coaching the Fighting Irish. Worse, most of Weis' positive work came during his first two seasons, when the Fighting Irish played in the 2006 Fiesta Bowl and 2007 Sugar Bowl.
After finishing 10-3 in 2006, the Fighting Irish lost 15 games in the past two seasons, the most defeats in school history during a two-year span. The 2007 team finished 3-9 -- the worst season in school history -- and lost to Navy to end Notre Dame's 43-game winning streak against the Midshipmen.
After last season's 7-6 finish, athletic director Jack Swarbrick spent several days evaluating the program's future. After a two-hour meeting with Weis, Swarbrick seemed confident his coach could turn the Fighting Irish around. Weis has seven years left on a 10-year contract, which is believed to pay him close to $4 million per season. The exact amount of Weis' buyout -- which the school would owe him if he were fired without cause -- isn't exactly known.
Heading into the 2009 season, with the Fighting Irish returning 18 starters and playing a somewhat watered-down schedule, Weis might need to lead his team to nine or 10 victories to prove his program is headed in the right direction.
"I'm not really worrying about the past," Weis told reporters at Notre Dame's media day earlier this month. "I'm really worried about going forward. I think right now the only thing I'm worried about is the start of this football season. I could sit there and tell you [what] lofty goals I have, my expectations. But guess what? It's time for us to back them up. That's what we have to do. The only way to back them up is by backing them up on the field."
2. Al Groh, Virginia
Just two years ago, Groh was named the ACC Coach of the Year, after the Cavaliers finished 9-4 and played in the 2008 Gator Bowl. But that season was sandwiched by 5-7 campaigns in 2006 and '08, in which Virginia finished poorly and missed bowl games.
Entering his ninth season as coach of his alma mater, Groh has made significant changes. The Cavaliers have four new assistant coaches, including former Kansas State coach Ron Prince, who returns to Virginia as the team's special-teams coordinator. Former Bowling Green coach Gregg Brandon was hired as offensive coordinator and installed a spread offense this spring. Brandon replaced Mike Groh, the head coach's son, who resigned after Virginia finished 114th in scoring among Football Bowl Subdivision teams in 2008.
Groh, 65, has three years left on a contract that pays him about $2 million annually. The school had the option of extending his contract for one year after the 2008 season, but declined to do so. Virginia officials wanted Groh to renegotiate his contract and reduce the deal's current buyout -- it would owe him about $2 million for each season left on the contract -- but he wouldn't do it.
So Groh heads into the 2009 season with his future at Virginia being pretty cloudy at best. The Cavaliers are picked to finish near the bottom of the ACC's Coastal Division.
"It's not about me," Groh told reporters at ACC media days last month. "It's about the team. I don't address it with me, so why would I address it with them?"
3. Steve Kragthorpe, Louisville
Louisville athletic director Tom Jurich insists 2009 isn't a "make-it-or-break-it" season for Kragthorpe. But after compiling an 11-13 record in his first two seasons at Louisville, Kragthorpe probably needs to at least lead the Cardinals to a bowl game, something he failed to do in 2007 and '08.
Kragthorpe inherited a program that won 41 of 50 games under former coach Bobby Petrino. The 2008 Louisville team, led by record-setting quarterback Brian Brohm, finished 6-6. The Cardinals were even worse last season, finishing 5-7 and losing their last five games, including an ugly 63-14 defeat against Rutgers in the finale.
The odds are stacked against Louisville to finish with a winning record in 2009. The schedule is very difficult, with road games at rival Kentucky, Utah, Cincinnati, West Virginia and South Florida. Although Jurich has a lot of faith in Kragthorpe, Cardinals fans want to start seeing some positive results.
4. George O'Leary, Central Florida
O'Leary led the Golden Knights to their first national bowl game in 2005 and first Conference USA championship in 2007. But Central Florida has never posted back-to-back winning seasons during his five-year tenure and his overall record is 26-36.
O'Leary's coaching methods were also questioned after the 2008 death of wide receiver Ereck Plancher, who died following an offseason workout. Although O'Leary and his staff were cleared after a university investigation, Plancher's parents sued the school for wrongful death in March.
The Golden Knights bring back 16 starters from last season's 4-8 team, including 10 on offense. UCF plays a difficult schedule, including nonconference games against Texas (road) and Miami (home), along with Conference USA road games at Southern Miss and East Carolina. A record similar to 2008 could spell the end of O'Leary's tenure in Orlando.
5. Mark Snyder, Marshall
The Thundering Herd haven't had a winning season since joining Conference USA in 2005, and each of the past four losing campaigns came during Snyder's watch. Snyder, a former Ohio State defensive coordinator, has a 16-31 record at his alma mater, including a 4-8 mark in 2008. Worse, home attendance at Joan C. Edwards Stadium dipped below an average of 25,000 per game last season.
Marshall brings back eight starters on defense, but still hasn't settled on a starting quarterback. The Thundering Herd went 1-5 in road games last season, and they play at Virginia Tech and West Virginia this year. Snyder might need to lead Marshall to a bowl game in 2009 to save his job.
1. Mike Sanford, UNLV
Sanford probably saved his job by leading the Rebels to consecutive overtime upsets at Arizona State and Iowa State last season. But the Rebels still finished 5-7, losing at San Diego State 42-21 in their finale. It was the Aztecs' only victory over a Mountain West Conference opponent last season.
Sanford has an 11-36 record in four seasons at UNLV, which has endured five straight losing campaigns.
2. Bill Lynch, Indiana
Lynch did a remarkable job leading the Hoosiers to a 7-6 record and an Insight Bowl appearance in 2007, after he replaced ailing Hoosiers coach Terry Hoeppner, who died of a brain tumor in June 2007.
But the Hoosiers slipped to 3-9 last year, including a 1-7 record against Big Ten foes. Lynch has three years left on his contract and his team needs to show improvement this season. The Hoosiers are picked to finish last in the Big Ten this season and will be without quarterback Kellen Lewis, who was dismissed from the team.
3. Mike Price, UTEP
After reviving his once-disgraced career with back-to-back 8-4 seasons at UTEP in 2004 and '05, Price's teams have limped to three straight losing campaigns. The Miners went 5-7 last season, dropping Price's overall record to 30-30 in five seasons at UTEP.
If UTEP can improve its porous defense, it might be a contender in Conference USA's West Division in 2009. If not, the Miners might be headed for their fourth straight losing season, which would be trouble for Price.
4. Randy Shannon, Miami
Shannon wasn't Miami's first choice to replace Larry Coker after the 2006 season, and he's had pretty mediocre results in his first two seasons coaching his alma mater. Shannon has done a nice job cleaning up the Hurricanes' off-field problems, but his 12-13 record leaves a lot to be desired at a place like Miami.
The Hurricanes finished 7-6 in 2008, losing their last three games after they were in contention for the ACC's Coastal Division title. With 18 starters coming back, Miami might be good enough to win 10 games in 2009. But its early schedule is brutal: at Florida State, home against Georgia Tech, at Virginia Tech and home against Oklahoma.
Shannon's contract expires after the 2010 season. The school was willing to offer him an extension this summer, but with only a modest raise. He's gambling the Hurricanes will be good in 2009 and even better in 2010. It's a big risk. Remember: Coker had a 60-15 record when the Hurricanes fired him.
5. Dan Hawkins, Colorado
After Hawkins compiled a 13-24 record in his first three seasons, "Hawk Love" might be running its course at Colorado. The Buffaloes started the 2008 season with a 3-0 record, but lost seven of their last nine games to finish 5-7.
Hawkins has yet to lead Colorado to a winning season -- the 2007 team finished 6-7 after losing to Alabama in the Independence Bowl -- but he seems confident his team will accomplish the feat in 2009. At the team's senior banquet in December, Hawkins told his players, "Ten wins and no excuses." Hawkins has said since then that his statement wasn't a guarantee the Buffaloes would win 10 games. But Colorado might need at least a winning record to keep him around.
6. Doug Martin, Kent State
Four Mid-American Conference teams made coaching changes after the 2008 season (a fifth coach left on his own), and at least three more coaches might be in danger of losing their jobs this season. Martin has a 19-39 record in five seasons at Kent State, which hasn't finished a season with a winning record since 2001. The Golden Flashes are picked to finish near the bottom of the MAC East.
7. Pat Hill, Fresno State
It's hard to imagine Hill being in trouble at Fresno State, but his contract expires after the 2010 season and the school hasn't extended it. Hill has a 92-61 record in 12 seasons at Fresno State, but the Bulldogs have been pretty mediocre recently, winning more than seven games only once in the past three seasons.
Fresno State finished 7-6 in 2008, including an ugly 61-10 loss to Boise State in the regular-season finale. Hill has led the Bulldogs to a bowl game nine times and might need to do it again to feel safe about his future.
8. Todd Dodge, North Texas
Dodge, who was hired after a highly successful career as a high school coach in Texas, was supposed to put the Mean Green back on top in the Sun Belt Conference. But they were at the bottom of the league in each of his first two seasons, with a combined record of 3-21.
Dodge's pass-happy offense has been pretty mediocre, averaging just more than three touchdowns per game. The North Texas defense has been atrocious, finishing last in scoring defense among FBS programs in each of the past two seasons.
9. J.D. Brookhart, Akron
Brookhart led the Zips to their first MAC championship and first bowl game in 2005, but the past three seasons have been pretty lean. The Zips haven't won more than five games in any of the past three seasons, not the kind of momentum a school wants moving into a new on-campus stadium.
Even during last season's 5-7 campaign, the Zips showed promise. They won at Syracuse 42-28 and nearly beat Cincinnati, losing 17-15 at home. But with a 27-33 record in five seasons, Brookhart probably needs to turn the Zips around in 2009.
10. Frank Solich, Ohio
Solich probably has more job security that the aforementioned MAC coaches, after the school extended his contract through the 2013 season. After guiding the Bobcats to their first bowl game in nearly 40 seasons in 2006, Solich's teams went 6-6 and 4-8 the next two seasons.
The Bobcats are picked to finish in the middle of the pack in the MAC East this season. Solich might need to show improvement from last season's disappointing campaign to feel truly safe.
1. Steve Spurrier, South Carolina
Spurrier can probably coach the Gamecocks as long as he wants, as long as they're playing in bowl games. But for a coach who led Florida to six SEC titles and the 1996 national championship, mediocrity gets old pretty quickly. Spurrier has a 28-22 record in his four seasons at South Carolina, including a 15-17 mark against SEC foes. The Gamecocks better get it turned around soon, or Spurrier might leave on his own.
2. Rich Rodriguez, Michigan
It's hard to imagine Rodriguez being fired after only two seasons, but he needs to avoid another eyesore like 2008. In Rodriguez's maiden voyage in the Big Ten, the Wolverines went 3-9, the worst season in school history, and lost to Toledo at home. Michigan fans knew they'd have to be patient while Rodriguez installed his spread offense, but they won't tolerate another season like last year.
3. Bret Bielema, Wisconsin
Bielema's job doesn't seem to be in immediate danger, but he needs to regain the momentum he lost after the 2007 season. Bielema became the first Wisconsin coach to win 10 games in his first season in 2006, and the Badgers went 9-4 the next season. But Wisconsin was a big disappointment last year, finishing 7-6 overall and 3-5 in the Big Ten.
Bielema was Barry Alvarez's hand-picked successor, and as long as Alvarez remains the school's athletic director, the Badgers would probably have to struggle mightily for a coaching change to be made.
4. Mike Sherman, Texas A&M
Sherman's first season at Texas A&M was a disaster, as the Aggies lost their opener to Arkansas State and finished 4-8. Sherman did a nice job of recruiting more speed, and he'll probably get a couple of seasons to get his players in place. But Texas A&M can't afford to fall further behind Big 12 South rivals Oklahoma, Oklahoma State, Texas and Texas Tech, so Sherman needs to turn the Aggies around quickly.
Mark Schlabach covers college football and men's college basketball for ESPN.com. You can contact him at email@example.com.