MYRTLE BEACH, SC (WBTW) – Beachgoers love nothing more than a hot summer day.

But Wednesday’s temperatures were more than hot; they were potentially dangerous.

Although heat indexes along the Grand Strand were well into the 100s, outside temperatures can be dwarfed by the ‘greenhouse’ sitting in your driveway:

Your car.

The National Highway Traffic Administration warns that in just 10 minutes, a car’s internal temperature can increase by 20 degrees.

We wanted to see it for ourselves. So we did an experiment.

Here’s what happened:

We set up a camera on the dashboard and got the car to a comfortable temperature. The thermometer read 88 degrees. Then we turned the car off and left the thermometer on the seat for 15 minutes.

It was close to 110 degrees by that time, but something else happened. Our camera overheated and wouldn’t record anymore.

And by the time 30 minutes had passed, the car’s temperature was already at 120 degrees. That’s 30 degrees in 30 minutes.

If that’s enough to shut down a camera, imagine what those temperatures could do to a person.

“They could pass away from that,” Lieutenant Jonathan Evans of Myrtle Beach Fire Department said.

He explained that children and pets should never be left in a car without air conditioning.

“It can be very dangerous especially on hot days,” he said. “It’s a 105 heat index outside. In the car, it could be upwards of 130, 140 degrees.”

Even on cooler days, he says, a car can become too hot for kids or pets.

“It could be 70 degrees, but inside (the car) you got the sun beaming down and it heats up like an oven,” he said. “It’s a whole lot warmer in the car because that heat can’t escape.”

Evans says MBFD gets more calls on pets than kids, but are always on the lookout for either stuck in hot cars.

Sometimes, he says, parents accidentally lock their children or pets in the car, and have to call to get them out.

“We do our best to get them out as soon as possible without breaking a window,” he said. “That’s obviously last resort. (But) it’s better to replace a window than to have something happen to that child.”

The NHTSA warns that children’s body temperatures rise three to five times faster than adults. And if their core internal temperature reaches 107 degrees, they could die.

As for how to avoid that- or any other harmful effects of heat, like heat strokes- Evans offers some tried and true pointers.

“Drink lots of water. Find shade when you can,” he said. “Check the back seat and make sure pets or kids are not there.”