The large digital thermometer attached to a car read 88 degrees when the St. Petersburg Fire and Rescue and the Suncoast Safe Kids Coalition started a recent demonstration.
The interior temperature quickly rose to 118 degrees, much higher than the temperatures pediatric surgeon Dr. Beth Walford says are potentially lethal.
"Once they get up to a certain temperature they start to have mental status changes where they're not as alert," said Walford, from All Children’s Hospital. "They can get nausea, vomiting, seizures, organ failure, and then when they hit about 107 is when we start seeing fatalities."
So far this year, 19 children in the United States have died after being left in hot cars, according to a San Francisco State University study. Two of those children were from Florida.
A 2-year-old girl in Sarasota died earlier this year after being left by her father who fell asleep when he went inside to get his phone charger. In another incident, a 9-month-old in Brevard County died when her father left her in his truck as he went to work. Both men have been charged with aggravated manslaughter.
And just this week, the Orange County Sheriff's Office is investigating the case of a 2-month-old baby girl left in a car outside a pediatrician's office. Though left in the car for about an hour, the baby is recovering at an Orlando hospital, the Associated Press reports.
Parents who leave their children in cars are often charged with anything from child neglect to murder, depending on the circumstances. But charging parents may not be the best way to prevent more deaths.
"Law enforcement individuals have been conflicted. In general they have accepted that it was a tragedy and that the parent forgot, but they feel an obligation to prosecute the parent. When a child dies people feel someone should pay the price," said Dr. David Diamond, a professor of neuroscience at the University of South Florida. He studies memory and forgetting.
He thinks parents leaving their kids in cars is a tragedy, but he doesn't think it's a crime.
"I've actually gotten to know many of these parents. I have seen their trauma," he said. "I've sat with them in their homes and I've talked with their families and I have talked with them in courtrooms when I've served as an expert witness to help explain to juries how this truly can happen to anyone."
Making examples of these parents may not be the best idea, Diamond says. It can make it seem like only bad parents forget their children, which he says is not the case.
"And parents who have said that they could never do this - in fact they are the very same parents who have forgotten the kids as well. So the first thing I think it's important to do is not be in denial," he said.
Florida is one of 20 states in the nation that has laws specific to leaving kids in cars. It is illegal for someone in Florida to leave a child 6-years-old or younger in a car for longer than 15 minutes.
Judith Scully, a law professor at Stetson University, says the law brings attention to the problem.
"Once you have a law, it does raise awareness of the general public about a particular issue" she said.
However, Diamond says that awareness alone may not prevent future incidents.
"They put the child in the car seat and almost instantly - that's what the evidence indicates - almost instantly they forget the child is in the car," he said.
Janette Fennell is the founder and president of KidsAndCars.org, a child safety organization. She says the law in Florida isn't good enough.
"You can't leave your child alone in a car for it's either like 5 minutes or 15 minutes. Well, there shouldn't be any amount of time that you leave a child alone in a car," she said.
Fennell thinks technology is the best solution to prevent parents from leaving kids in cars.
"You know you can't educate your brain or your memory not to fail, that's impossible, so that's why technology will be important for the future," she said.
There have been some attempts to create gadgets to fill in the memory gaps. The Suddenly Safe Pressure Pad, the ChildMinder Smart Clip System, and the ChildMinder Smart Pad are all products that are currently on the market. However, a 2012 study by the National Highway Safety Traffic Administration found all of them to be unreliable.
Fennell's child safety group is petitioning the White House to authorize funding for the Department of Transportation to research technology that could prevent kids from being forgotten in a vehicle. They also want auto makers eventually to be required to install this technology in all vehicles. The petition needs 100,000 signatures by August 13.
"It's really hard to believe that a reminder couldn't be added for a child because in today's world you really can't buy a car that either doesn't automatically turn off your headlights or remind you to turn off your headlights," Fennell said.
Until foolproof technologies are widely available, St. Petersburg Fire and Rescue and the Suncoast Safe Kids Coalition are providing reminders for parents whenever they can.
At the hot car demonstration in June, Deputy Fire Marshal Lt. Steve Lawrence said parents can use technology they already have to remember their children.
"We're encouraging people to also maybe set an alarm on your phone, ok, as a reminder, hey, we have a child in the back seat as well," he said.
Lawrence also said St. Petersburg Fire and Rescue is providing cards that can be hung from the rearview mirror of a car that say "Where's Baby?"
--Health News Florida is part of WUSF Public Media. For more health news, visit HealthNewsFlorida.org.