Of course fireworks are popular in the USA around July 4th. But there is perhaps no simpler firework than the basic sparkler. The sparkler is usually some type of stick with a thick paste of a metallic fuel. When this fuel burns, it produces tiny glowing sparks that shoot off in all directions.
Of course, there are some interesting physics here too. It's not just sparklers. There are always cool things around us that show both basic and advanced physics concepts. For now, we will just look at the sparkler. Here we go.
Temperature vs. Heat
These sparks from the sparkler are HOT. I mean super hot. It depends on the kind of sparkler, but the temperature of these sparks can be anywhere from 1800°F to 3000°F (1000°C – 1600°C). How hot is that? Here are some temperatures of some other things you might have seen.
Human body = 98°F (37°C)
Your oven can get up to 550°F, but the element (the heating part) can get up to 1500°F (815°C).
The glowing filament in an incandescent lightbulb is about 4500°F (2500°C).
Iron melts at 2800°F (1500°C).
The temperature of a spark from a sparkler is very high. 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.