The science behind the ‘5 second rule’

5 second rule

We must have all had that devastating moment, when you are holding the most tantalising piece of food in your hand, then in slow motion the precious morsel slips out of your grip and tumbles on to the floor. Absolutely heartbreaking stuff, until of course somebody comforts you with three magical words – 5 second rule – and you realise this food is still fit for consumption. It is still OK to eat right?? Right??

Believe it or not people have researched whether there is truth in this rule, and the results may actually surprise you.

The research:

The logic behind this rule is that germs from the floor wouldn’t have enough time get all up in your food in just 5 seconds, so the food should be fine if you pick it up quickly. The research tested the rule based on this idea, and placed items of food on floors covered in bacteria for varying amounts of time and then measured how much bacteria had got into the food.

The results:

The less time food was on the floor, the less bacteria was able to transfer in to the food – which shows living by the 5 second rule isn’t a bad idea.

However, what did matter even more was the amount of bacteria on the floor to begin with, if your floor is infested with crap, the bacteria will likely get into your food, even if you do pick it up fairly quickly – but you would have to drop the food in that exact spot where the bacteria is for this to be a problem.

They also found that you can add more time on to the 5 second rule if the food is dropped on carpet. Bacteria transferred to food much slower on carpet compared to wood or tiles. This means if you drop food on the carpet it is likely to be safe – it just might be a bit furry.

Why does toast always drop butter side down?

Whilst on the topic of dropping food, I thought I would try and find an answer to why toast pretty much always falls butter side down. In most situations when we drop toast we knock it off a kitchen counter or a dining table, and the ‘knocking off’ motion as well as the difference in drag between the side with butter on (no air holes) and the plain side (loads of air holes) tends to give the toast some rotation in it’s flight to the floor. But, because our kitchen units, dining tables and sofas aren’t that tall, the toast can only manage about half of its rotation before it hits the floor, and a half rotation usually results in the toast flipping just enough so the butter side is facing the floor, absolutely gutting stuff. Apparently if you drop toast from a bigger height it will have less chance of falling butter side down as it will be able to complete the rotation before meeting the floor.

So there you have it, 5 second rule is a-ok, particularly with carpet. I have once again answered one of life’s big questions using science – you can thank me with a cheeky retweet or follow.

Till next time,




The science behind why getting kicked in the balls hurts so much

Hit in groin

The high pitch groan, the grabbing of the crotch and a staggered drop to the floor. All tell tale signs of a man having been kicked in his special place. A pain apparently so bad that it justifies a grown man squealing like a prepubescent chorister. Now I don’t have testicles myself, being a woman and all that, so I have to take your word for it men, that this really does hurt that badly. Because I’m all about answering life’s important questions, I have looked into the science behind why being hit below the belt really is so painful.

Testicles are really exposed:

Most parts of our body are protected by some muscle, bone or cartilage, but your balls aren’t quite so lucky. This leaves them in a really vulnerable position so any physical impact on them will really hurt with no muscles etc to soften the blow – unlucky lads.

Testicles are covered in nociceptors:

A nociceptor is a type of nerve that reacts specifically to pain, and they only send signals once a certain pain threshold is reached. Because the testicles are absolutely covered in these, it makes them super sensitive to pain.

Here’s how it works: your balls get hit, the many nociceptors are activated and send loads of pain signals to the brain, the brain then responds by causing the release of a substance which makes us feel a physical pain, which you very quickly react to.

Men can often get headaches when hit in the special place too, this is because the brain also releases endorphins in response to the pain, which depletes some of the oxygen available in the brain – as if you didn’t have enough to deal with?  

Testicles are connected to nerves in internal organs:

Men will know all too well that when kicked downstairs the pain spreads all across the abdomen. This is because testicles are linked to lots of nerves in the stomach. Balls also link up with the vagus nerve, which connects to the part of the brain that controls vomiting. This not only explains the pain but the other symptoms that make men a total mess in this situation, like nausea.

What hurts more – being kicked in the balls or giving birth?

This really is one of the biggest debates in life. Until recent years nobody thought anyone could ever experience both, so this debate has been left unanswered. However, fabulous work in pain simulation is allowing us to have a bit more of an insight.

These wives managed to persuade their husbands to experience the pain of muscular contractions in labour:

It would be interesting to hear what these men thought was more painful, and I think I might be able to hazard a guess watching their reactions here. Maybe if somebody developed a simulator for the pain of being kicked in the balls for women to try then we could really settle this debate once and for all, (can’t say I will be volunteering for that one though).

Till next time,