Bake cookies in the car? Let’s see if that checks out…

Scott Sutherland

Yesterday, Toronto Police Service Detective Jeff Bangild conducted a sweet little experiment in his car during the day, putting some cookies in there to see if they'd bake in the sweltering heat we're getting in the GTA this week.

I'm not sure how many others are giving this a try themselves, but I'm giving it a go, all in the name of science!

It's a pretty standard experimental setup...

• Cookie dough
• Baking Sheet
• Thermometer
• Standard 4-wheeled vehicle with infrared radiation-trapping windows
• Blazing-hot sun

The weather outside the car was 33°C, with a humidex of 42.

As the thermometer shows, the temperature in the car was already at 45°C when I started the experiment. By the way, based on today's humidity, the inside of the car would have a humidex of about 54. According to the scale of the index, that's the point at which heat stroke is imminent. Given that the car had only been out in the sun for about half an hour at that point, you can see why it's not a good idea to leave a child or pet in the car on a day like today.

Update #1: Back from the car and we have some progress!

After roughly an hour, they're about where they usually are after 10 minutes in my oven.

I don't know about you, but I always open the oven door for a closer look. Wow, temperature up to 60°C! That's only one-third the recommended oven temperature for baking, but it was enough to make me instantly break out into a sweat.

Update #2: Not much progress this time, except some slightly creepy-looking white bubbles on the edges of the 'cookies' (if we can still call them that):

As you can see, the temperature inside the car actually dropped 10 degrees. This was likely from opening the door, and the fact that the clouds rolling in after my last update — those associated with the severe thunderstorm watches and warnings in the GTA — essentially turned the oven down.

Update #3: Final judgement is that it didn't work out. The temperature didn't get back up above 50°C, even after the car had more direct sunlight. The cookies definitely got crispy on the top, even as of Update #2, and they were probably cooked most of the way, but looking at them, I probably wouldn't trust one enough to eat it:

So, they certainly didn't turn out as good as Detective Bangild's cookies did, but my 'control group' (baked at the right temperature, for the right time, in my oven) worked out exceptionally well!

There were a couple of things that made the difference between our two car-cookie experiments.

For one, the skies were 'mainly sunny' and 'partly cloudy' yesterday, and they're 'mainly cloudy' today, and the amount of sunshine that gets into the car is very important. Glass lets sunlight pass through it, but it blocks heat radiation. Therefore, the more sunlight that shines into the car, the more heat radiation that will build up inside the car and be trapped there by the windows.

Second, from what it looks like, Detective Bangild took the 24 dough pieces and made them into 12 cookies, whereas I kept them as they were so that I could bake my 'control group' batch. So, Detective Bangild's cookies were thicker, thus they weren't as 'vulnerable' to the humidity in the car (an oven is a dry heat , whereas the car is a bit more of a sauna), and they probably cooked a bit better (at least he didn't get sick when he tried one).

[ More Geekquinox: Canada’s humidex: confusing, flawed, but life-saving ]

However, the message that Detective Bangild was trying to get across was about how hot it gets inside a car, and my experiment showed it as well.

The humidity in the car (about the same as outside) was making it feel about 10 degrees hotter than the temperature actually was. So, when the car was in full sunshine and the inside was at 60°C, the humidex was around 70! That's well above that dangerous 'heat stroke' level! Even when the combination of opening the door and the clouds rolling in dropped the temperature to 50°C, the humidex was around 60! So, even if it's cloudy or you open the doors a few times to vent the heat, it's still dangerous!

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