Super Science: Conduction, Convection, and Radiation

Heat science is one of my favorites! First of all, let's start with how heat is made.

When an object moves very quickly, it generates heat. This is because when a molecule bumps into another molecule (everything is made up of many, many molecules) the molecules bump into other molecules and charges them off. Think of it like you have a line of dominoes stretching on and on and you push the first domino down. All of the other dominoes fall down, toppling over one another in a chain reaction.

The same goes for the molecules. Except, it's more like you have a bunch of beach balls bouncing around in a confined space. They keep on knocking into each other. The molecules bump into the other molecules over and over, faster and faster. Soon, they a generating a lot of heat.

This is convection. When a heat source brushes against, or rubs, or touches another thing, like a burner and a pot. (Solids, especially as medals, are the best conductors of heat because they have the most molecules) The burner generates heat, and the pot touching the burner begins to heat up. Then, it heats up the contents in it (water, vegetables, etc.). This is conduction at work! First the medal platform of the burner heats up, then the medal of the pot, and then the contents.

That brings us to radiation. Let's think about that burner. How does it heat up the pot, exactly? Radiation. The burner radiates heat.

The Sun has a radiation layer, or radiative layer. This is the layer that warms the Earth. The Sun radiates heat to Earth.

Radiation occurs when a object generating heat (the Sun, the burner) transfers it to another object (Earth, the pot). Like when a cat sits on your lap. You start feeling warm, and then warmer. The cat, (like all other mammals and warmblooded animals) is warm, and radiates heat to your lap. Conduction is also working in this case.

There is also another why for heat to transfer. This is called convection. Convection is when hot and cool air mingle together and make an even temperature. Wind currents help to make this process happen.

When the Sun heats the Earth, it does not heat it entirely evenly. There are warmer spots and cooler spots that can be very far, or very near, to each other. When the wind blows, it moves this air and mixes the different temperatures together. Sort of like when you're mixing a cake mix. There are dryer parts and wetter parts, like hotter and cooler air. When you stir, it becomes smooth and evenly mixed. When you stir, it's like when the wind blows. The wind currents are like the spoon. They mix the air to make the temperature even.

Let's think about that pot again. Conduction is working. The burner is hot, and when the metal meets metal, the pot heats up. When the pot (touching the content) is heated, the food inside of it is heated. Conduction is behind your food getting cooked.

Radiation is also at work. Heat is radiating from the burner, as it does from the Sun. This is also an important part of the process of cooking the food. Without radiation, conduction wouldn't have a chance to work.

Believe it or not, convection also plays a part in this. Conduction heats the air around the pot. It mixes in with the cooler air. Have you ever stood by the stove as your food is cooking? Notice how the air is warmer there, around the pot and in the kitchen, then it is out of the kitchen. If you are steaming your food, conduction is vital.

First the heat radiates from the burner, then it heats the metal top. Conduction brings heat to the pot, then to the food. Convection makes the air warm. If you are steaming veggies or another food you, convection is the cause of the steaming process ever getting finished, and started!

The next time you are cooking pasta, or steaming veggies, remember conduction, convection, and radiation. The next time you are playing with your dominoes, remember molecules. Remember the building blocks of heat.

-KittyLover8
© 2012

All You Need to Know About BUBBLES

Chapter I

Pop!

A question wondered by many people is, "Why do bubbles pop?"

There are multiple answers to this question.  Let's take a look at a few of the reasons why bubbles pop.

One of the reasons why your bubble might pop is the wind. The pressure of the air opposite of the direction the wind is blowing and the force of the wind on the other side is to much, and your bubble will pop on a windy, or even slightly breezy, day.

Another reason why your bubbles are popping is because of water evaporation. Water evaporation is a cycle that is essential life, including plants, animals, and all other organisms. Here is a diagram showing how the water cycle works:

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1. The clouds full up with water and rain.

2. The  water collects on the ground, replenishing lakes and ponds, and forming puddles.

3. The water is soaked into the ground and forms underground rivers.

4. The water from the underground rivers collects onto the land and forms a lake.

5. The water in the lake or other water source is evaporated into the air and becomes water vapor.

6. The water vapor clumps together and forms clouds.

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And that is how the water cycle works. The cycle shown is the diagram above on and on to infinity as long as the clouds have rain and the underground rivers have water.

So, let's continue talking about bubbles. When the water in the bubble solution used to make the bubbles evaporates, the bubbles become to dry and pop.

Because it is the Sun that makes water, and bubbles, evaporate, making your bubbles in the shade is one way you can stop your bubbles from popping so quickly. Another way you can do this is to blow your bubbles after a rainstorm. The air is filled with moisture and water vapor after it rains. Bubbles seem to last forever after a rainstorm.

Also, keep your bubble-blowing tools moist. If a bubble touches something dry, it will pop. If your tools are wet and covered with the bubble solution, it will be much easier to make bubbles.

Fun Fact About Bubbles

If you puncture a bubble with a nail that is wet, the bubble will not pop! If the nail is dry....Well, that's a different story.

Colorful Bubbles.

Why are bubbles colorful?  And why, on other occasions,  are they almost transparent or aren't as colorful? Why?

The answer these questions is almost the same as as the answer to the question, "How are rainbows made?" Two words: Light reflection.

When the light from the Sun, or a lamp, or another light source, reflects off of water, like rain or a bubble, the light is reflected back to your eyes as color. That is the simple way of explaining it. But let's go more into the answer to the question, "Why are bubbles colorful?"

This question has been briefly answered in the paragraph above, but let's show what happens in another diagram:

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1. Rays of light from the Sun head toward the bubble.

2. Light is reflected  off of the inner and outer layers of the bubble.

3. The light rays from the bubble travel back to your eyes in the form of beautiful colors. ___________________________________________________________

Let's explain that more thoroughly.  You may be wondering, "What are the inner and outer layers of a bubble?"

The outer layer of the bubble is only a few millionths of an inch thick. This is the layer that you see when you look at a bubble. Bubbles can't be died a color because this layer is to thin to hold the dye.

The inner layer is also, like the outer layer, only millionths of an inch thick. This layer is inside of the bubble and is left unseen.

When light from a light source meets a bubble, light is reflected off of the inner layer and to the outer layer. Then light from the outer layer is reflected to your eyes. You see this light as color.

Now, for your other question, "Why, on other occasions,  are they almost transparent or aren't as colorful?"

The answer is that, as the bubble floats around in the air, the inner and outer layers come closer and closer together with the passing time. As the layers press closer together, the joint rays of light begin to part. As they part, the color grows weaker, and weaker, and weaker still, until you can hardly see any color, or bubble, for that matter, at all.

So, that's how it works. In short, it goes like this. The inner layer gets nearer and near to the outer layer as the bubble ages. And as the layers get closer together, the color fades.

-KittyLover8
© 2012

About Science Lab

Science Lab is a blog that is all about, well, science! I think that science is very interesting. I will be posting science papers called Super Science and short books titled All you Need to Know About_____.

My favorite science subjects are heat energy (also called thermal energy), sound energy, and electrical energy. I also love learning and reading about molecule (also called particles)!

I also have two other blogs, The Purple Paw and The Purple Paw Characters.


Click here far a link to The Purple Paw. Click here for a link to The Purple Paw Characters.


-KittyLover8