Hello and welcome back to another episode of Physics Partner. Today we are going to tackle a fascinating topic in physics viscosity. So what is viscosity? Simply it refers to the internal friction or resistance that exists between molecules of a fluid which opposes any kind of external force that is trying to move it. Let's try to dive in a little deeper. In physics, viscosity can be defined as the major of the resistance of a fluid to flow. To be more precise, it is defined as the ratio of the force required to move a layer of the fluid over a specific surface area to the velocity of that layer. To illustrate, let's consider different fluids, such as water, honey and chocolate syrup. We all know that, if we pour water, it flows quickly and smoothly, whereas honey and chocolate syrup are highly viscous, meaning that flow very slowly and with high resistance almost like a thick liquid. In fact, the viscosity of a fluid depends on when its composition and the number and the size of the particle it contains. For example, the viscosity of water changes with temperature, as the temperature decreases, the velocity increases. But why is viscosity important in physics? Actually the relationship between viscosity and the force required to move a fluid can help us understand various physical phenomena, such as the dynamic of fluids in motion and the resistance of fluids to different types of deformations. For instance, a high-riskest fluid, such as molten glass, has the ability to resist deformation, which is useful in forming glass structure like bottles and vases. Now let's explore the law of viscosity, which is also called as Newton's law of viscosity. This law states that the shear stress within a fluid is directly proportional to the velocity gradient of the fluid. Shear stress refers to the amount of stress or force required to deform a fluid, while velocity gradient refers to the rate of change of velocity within a fluid. In simple terms, the law of viscosity tells us that as we move deeper into a fluid, the level of resistance increases. And by slowing down the velocity of the fluid, this principle is applied in a wide range of fields, including lubrication, chemical engineering and meteorology. Let's discuss some real-life examples of viscosity. One of the most relatable examples is the pain industry. The viscosity of pain determines its consistency and how it will flow when applied to a surface. Painting manufacturers carefully control the viscosity of their products to ensure that they are easy to apply, provide good coverage and dry evenly. Without an understanding of viscosity, the pain industry would struggle to produce high quality products that meet the needs of customers. Another example comes from the world of medical science, a blood clot. A blood clot comes from in our body due to a very high viscosity of the blood, which helps to prevent excessive bleeding and form a scab. However, in some cases, low viscosity of blood can lead to blood clots, which could potentially be fatal. So maintaining a balance of viscosity is important for our health. One more interesting example comes from the study of glaciers, where a viscosity plays a key role in determining how they move and flow. Glaciers are made of ice, which are solid particles, but over time, they tend to behave like fluids due to their high viscosity. As a result, they exert a significant amount of pressure and force on the underlying rocks and soil, causing erosion and shaping the earth landscape. To wrap up, it's clear that the concept of viscosity extends beyond just the world of physics and impact our daily lives in multiple ways. So I think it's enough for today. So thank you very much for listening and watching. I hope you enjoyed the video. I hope this video is useful for you. So take care of yourself and don't hesitate to write an email if you have any question, Q.R.Y. suggestion and even classes are required. Take care of yourself meanwhile. See you in the next video. Goodbye.