Lately I’ve been thinking of how we’re moving more and more to a world where humans will start merging with technology. We’re already carrying our phones around nearly every minute of every day but at least we keep them in our pockets. Watches are always on our wrists and with augmented reality the permanently attached technologies will only grow.

At some point they’ll just become part of our bodies and I was curious what additional energy we’d need to consume in order to power these devices. A naive calculation makes it seem that our devices are incredibly cheap to power. An iPhone 6S comes with 6.61 Watt hour battery which is 23,796 Watt seconds (6.61 * 60 * 60). And since a single calorie is equivalent to 4.1868 Watt seconds with some simple math we get that an iPhone 6s battery is equivalent to 5683 calories. But these are true calories and not what’s actually listed on food labels. Food labels list kilocalories so remarkably the capacity of an iPhone 6s is fewer than 6 “food” calories. For context 6 calories is what one gets from a large strawberry. I charge my phone once a day and I’m shocked that the energy in a strawberry would be able power my phone for a single day.

I’m sure the math is not that simple and there’s a lot of factors I’m not taking into account but it’s amazing to think how incredibly efficient smartphones are given all they do. I can imagine a future where instead of having separate chargers for our devices we can power them through our bodies. And while this vision is reminiscent of The Matrix and is a bit dystopian it does have its appeal and I suspect we’re getting closer and closer.