Knowbots, Knowledge, Robots


Slow down Li Na! You're making me look like a lazy-bot! Ha

Take a look down at the skin on your arm – did you know there are hundreds of things happening to it right now? It’s detecting the temperature of the room you’re in, and it may be sensing the feeling of your clothing. It’s also renewing itself! 

Your skin is a very important piece of protection for your body. It is a waterproof barrier to the environment that keeps dirt and germs away and filters some of the harmful rays in sunlight. It helps your body absorb vitamin D. Plus, it’s where one of your five senses is kept – touch! There are thousands of sensors throughout your skin that can detect heat, cold, pain, and other sensations (tickles, too!). 

Your skin also keeps your body at the right temperature by sweating when you run, like Li Na's right now, and controlling your blood vessels too. When you’re really hot, your skin produces sweat to cool you down. It can also make your blood vessels wider, allowing more blood to flow and for your body to lose heat. When you’re cold, it does the opposite by narrowing your blood vessels. Now you know why you get red in the face after exercising! 

Skin is technically the largest organ in your body. It’s around two square metres big in adults and weighs around five kilograms. But, it’s also very thin – between 0.02mm thick on your eyelids and around your eyes, and 1.4mm thick on your palms and the soles of your feet.  

No matter the thickness of the skin, there are always three layers. The ​epidermis ​is the part you can see. It’s the outer layer of skin that acts as a protective barrier against the environment. The epidermis is always doing something: at the bottom, it is producing new skin cells that eventually start moving to the top of the epidermis. This takes between two weeks and one month. As the new cells rise up, old cells die and move to the top – so you’re basically constantly shedding your skin, like a snake! Every ​minute​, you lose around 30,000 to 40,000 dead skin cells, which totals four kilograms every year. Wow! 

Next is the ​dermis​, which contains blood vessels, oil glands, sweat glands, and nerve endings. Beneath that is ​subcutaneous fat​. Sub...cue..ta… that word makes my bolts spin! Basically, this fat layer keeps your body warm and acts as a shock absorber if you accidentally hit something. This is also where you’ll find hair follicles, which are the points where your hairs start to grow. 

How cool is skin, huh? I bet you’ll never look at it the same way again!

Vitamin D ​- a vitamin that helps your body absorb calcium and phosphorus. You can get vitamin D from the sun! 
Sensor ​- a tool in your skin that lets you feel things. 
Blood vessels ​- tubes that run through your body carrying blood. 
Cells ​- tiny little units that make up all living things. Find out more about cells ​here​. 
Glands ​- an organ that discharges particular chemicals for use in the body. 
Nerve endings ​- the millions of points on the body that detect things and send messages to the brain. 

1. The average person has around 300 million skin cells.
2. Some sources say the dust in your house is 50% dead skin cells.
3. Each five cm square of skin can have up to 600 sweat glands.

1. Your skin is waterproof – true or false?
2. Which sense is kept in the skin?
3. How much does an adult’s skin usually weigh?
4. The epidermis is the outer layer of your skin – true or false?
5. How many dead skin cells do you lose every minute?

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