Basic Physics Tutorials

Equation of continuity

Article about Equation of continuity

Try to open the water tap slowly while paying attention to the speed of the water coming out of the mouth of the faucet. Now compare, where is the rate of water flow faster, when the mouth of the faucet is closed or not? Why is that? To understand this, please learn the continuity equation.

Streamline

Equation of continuity 1 In a steady stream, the speed of each fluid particle at a point, say point A is always the same. When passing point B, the velocity of the fluid particles may change. However, when arriving at point B, the fluid particles that follow from behind flow at the same speed as the fluid particles that precede it. Likewise when coming at point C and so on. The Flow Line is a curve that connects points A, B, and C.

Black principle

1. Definition of Black principle

If we mix hot and cold water in an open container (for example a bucket), heat transfer from hot water to cold water. Because the container is open, then some heat moves into the air. The container also becomes warmer. Heat released by hot water is not only absorbed by cold water, but also absorbed by atmosphere and containers. In this case, the bucket is a non-isolated system. When we mix hot and cold water in a closed thermos, heat transfer from hot water to cold water. Thermos are isolated systems, so no heat moves into the air or a thermos. Cold water only absorbs the heat released by hot water until the mixture of hot water and cold water reaches the thermal equilibrium.

Heat transfer by radiation

1. Definition of the heat transfer by radiation

How does it feel if you wear black clothes on a hot day, or when are you exercising during the day? Compare with when you wear white clothes? If you wear black clothes during the day, then you feel hot. Why is that? The distance between the sun and the earth in the morning is almost the same as the distance between the sun and the earth during the day and evening. Then why are the mornings and evenings cooler, hotter during the day? The answers to these questions are related to heat transfer by radiation.

Heat transfer by convection

Article about The heat transfer by convection

Ever been by the beach when it was sunny? On a clear day, on the beach, there is always wind blowing from the sea. Why is there always a wind on the beach, and why do the sea breeze (winds blowing from the sea to the land) occur during the day, the land breeze (winds blowing from land to sea) occur at night? Why in the rainy season can cloud come down to the slopes? Why does the wind feel cool? The answers to these questions relate to the specific heat of land and sea, expansion, density, and heat transfer by convection!

Heat transfer by conduction

1. Definition of the heat transfer by conduction

If you sit in a wooden chair, the surface of the wooden chair becomes warm. Conversely, if you sit in a chair made of plastic or metal, the surface of a metal or plastic chair does not feel warm after sitting. Why is the surface of the wooden chair heated, while the metal chair surface is not? Why can sleep on a cold floor without a mattress cause pain? Have you ever worn an anti-cold jacket? Why are most anti-cold jackets made of wool? There are still many things that can be considered and questioned related to the subject of heat transfer by conduction.

Latent heat specific heat and heat capacity

Article about Latent heat specific heat and heat capacity

If you put a mercury thermometer into a container containing a mixture of cold water and ice, you will observe after moving downwards, the surface of the mercury stops moving. Mercury’s surface stops moving after reaching the temperature of the freezing point of the water (0 ^oC). If the container is open, heat flows from the air that has the high temperature to the mixture of ice and cold water. The addition of heat from the air causes the ice to melt. As long as ice melts, does the temperature of the mixture of the ice and cold water change? As long as ice melts, the temperature of the mixture of water and ice does not change.

Definition of heat Mechanical equivalent of heat Equation of heat

Article Definition of heat Mechanical equivalent of heat Equation of heat

1. Definition of heat

If objects that have temperature differences touch each other, there will be heat transfer from high-temperature objects to low-temperature objects. Heat transfer stops after touching objects reach the same temperature. For example, if we mix hot water with cold water, usually heat moves from hot water to cold water. When we put hot iron into cold water, heat moves from iron to water. Heat will stop flowing after iron and water reach the same temperature. When a nurse attaches a thermometer to your body, heat moves from

Article about Anomalous behavior of water below 4°C

Each object expands (the volume of objects increases) when the temperature increases, and objects shrink (the volume of objects decreases) when the temperature decreases. Water also expands when the temperature increases and shrinks when the temperature decreases, but not at 0 ^oC – 4 ^oC. Between 0 °C and 4 °C, the volume of water decreases (water shrinks) as temperature increases. If we heat the water at 0 ^oC, the water gets hotter, the water volume decreases. The shrinkage process stops when the water reaches 4 ^oC. Above 4 ^oC, the volume of water increases as temperature increases. Instead, water expands (the volume of water increases) when the temperature decreases from 4^oC to 0 ^oC.

Linear expansion

Most solid objects experience a linear expansion when the temperature changes. The linear expansion is the length of the object increases or the length of the object decreases. Usually, the length of the object increases when the temperature increases, whereas the length of the object decreases when the temperature drops. You might think that linear expansion can only occur on objects such as thin wires. For example, look at a car that is parked on the side of the road, so it is exposed to the sun. When the car overheats, the iron plate can get thicker, or the side length can increase. Roofs of houses made of zinc can also experience expansion. In this case, when zinc is overheated, the edges of zinc increase in width and zinc can even get thicker. The same thing happened to the railroad tracks and iron or steel on the bridge.

Conversion of temperature scale

Article about Conversion of temperature scale

The Celsius scale and the Fahrenheit scale are different temperature scales. If the temperature of an object is measured and expressed on a Celsius scale, then we want to state the temperature of the object on the Fahrenheit scale then we change it from the Celsius scale to the Fahrenheit scale. In this section, we learn to change or convert a temperature scale.

At a pressure of 1 atm, the temperature of the freezing point for the Celsius thermometer = 0 ^oC, while the Fahrenheit thermometer = 32 ^oF. Conversely, at a pressure of 1 atm, the temperature of the boiling point for a Celsius scale thermometer = 100^oC, while a thermometer with a Fahrenheit scale = 212 ^oF.