The Awesome Physics in a Simple Sparkler | WIRED. <– There’s a sweet video too. Check it out!
Wired gives a great example of wondrous detail about the small things in life we usually just pass by.
Aren’t these sparklers dangerous? Actually, they can be when not used safely. But if one of these sparks hits your skin, it’s not going to do serious damage. Why not? This is because there is a difference between temperature and energy. The hot spark has what we call thermal energy. The thermal energy an object has depends on its temperature, its mass and the type of material it is made from. Since these sparks have such low mass, they don’t have very much thermal energy. Without much energy, they don’t have the capacity to do very much damage to your skin. – Rhett Allain
Isn’t that mind blowing, you’re holding 1300°F in your hand and yet it is made in such a manner that it won’t harm you!
Photo by: Rhett Allain
There’s another thing that makes sparklers safe and it is size.
Doubling the size increases the thermal energy by a factor of 8 and increases the surface area by 4. It has way more energy but can only cool off a little bit faster. This isn’t a big surprise, so don’t act like it is. What cools off faster? Big hot muffins or small hot muffins? You know the smaller muffins get cooler quicker.
The same thing happens with these sparks. – Rhett Allain
Rhett spells out a lot of other cool things about these tiny fireworks in this fascinating article. Please be sure to read the full version on Wired.
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