Kia Ora Everybody! This week in Science, we have been learning about Convection, Conduction, Expansion, Contraction, and Diffusion. For this blog, I have been given a task to write about atleast two of these topics, and I have chose to write more about Expansion and Contraction.
Convection is when areas of liquids or gases with high thermal energy, their particles will rise, but liquids or gases with low thermal energy, their particles will just fall. When a particle push a molecule away, thats when the convection occures because of the thermal energy. And it will make the gas or liquid less dense in larger spaces, causing the particles to float.
Conduction is when particles with thermal enegry vibrates, and some of their thermal energy will pass on to another particle. A metal is a conductor because it transfers the thermal energy into the particles really fast, while plastic and glass do it way slower, and they are terrible conductors.
Diffusion is when the smell of the particles can spread throughout the air, like perfume. Also when mixing colour dye to water, the boiled water can diffuse the colour dye faster on it’s own, but the colder water will take a while for the colour dye to diffuse on it’s own. Diffusion happens when particles bounce around and push one another away. Gases diffuse to fill their container entirely, but solids won’t diffuse unless something can break the bonds holding the particles together, like salt dissolving in water.
Now lets talk more about Expansion and Contraction.
Expansion
Expansion is when the particles vibrate faster because of the thermal enegry when heat is added. The particles will push each other and vibrate when the thermal enegry is added making the solids, liquids, or gases to expand slowly. They expand really slowly that we won’t be able to notice it and it may look like nothing has happened. But the particles really do expand. For example, we did this experiment with a ring, and a ball. At first the ring cannot fit into the ball cause the metal particles don’t have any thermal energy. But when the heat is added into the ring, metal particles of the ring will start to vibrate a lot more because of the thermal energy, making it expand. And once heated, the ring can finally fit through the ball easily.
Contraction
is quite the opposite of Expansion. When the thermal energy is removed from the particles. The particles will still vibrate, but a lot slower. Before it had thermal energy and it made it vibrate faster and pushing eachother, and expanding. But now it will start to come back together like shrinking, which is called Contraction. So when cooled, the particles will be contracted. In the experiment, when the metal particles of the ring have expanded with heat and thermal energy, the ring could be dipped in cold water, making the metal particles of the ring vibrate slower and contract. And the ring won’t be able to fit through the ball again.