chemistry presentation. related to atoms and molecules and some also to pressure
TRANSCRIPT
•What is pressure?
•Applications of pressure in daily life.
•The three states of matter.
•Effect of Pressure on states of matter.
•Summary.
•Ending.
Sometimes handbags have a thin strap. When the strap comes in contact with our shoulders, it hurts us and we feel pain.. This is because when the surface area is less the impact of the pressure is more and when the surface area is more the impact of the pressure is less.. This is the reason that handbags and even schoolbags have a broader strap
Lets take a situation of fixing a broken table using the nail. First, we take a nail whose tip is blunt. When a force is applied to hit the nail, the nail does not buried into the table. This is because by the large area of the nail tip in contact with the table produce low pressure. The larger the tip area of the nail, the more time taken to completely immerse the nail to the table. Next, we take a nail whose tip is sharp. The small area of the nail tip in contact with the table produce high pressure and make hitting the nail into the table become easier. The smaller the tip area of the nail, the less time taken to completely immerse the nail to the table.
Massage is one type of application of pressure. By doing this it reflexes the feet, hands, ears and their referral areas within zone related areas, which correspond to every part, gland and organ of the body. This is because while giving pressure it pushes the nerves and we don’t get any pain later.
When we pull the plunger out on a syringe it causes the volume within the chamber to increase. As we know, this causes the pressure do the opposite, which creates a vacuum attempting to re-pressurize back to atmospheric levels. Since the only fluid available on the other side of the needle tends to be a liquid such as blood, which gets sucked into the chamber, reducing the volume and increasing the pressure back to where it wants to be.
We know that before we spray a can of paint we are suppose to shake it up for a while, listening as a ball bearing rattles around inside. The can is sealed, preventing this gas from boiling and turning into a gaseous state. That is, until we push down the nozzle. The moment the nozzle goes down, and the seal is released, there is now an escape route. The propellant instantly boils and expands into a gas and pushes down on the product trying to escape the high pressure, and expand it’s volume the atmosphere where there is less pressure. This forces the product to shoot out from the nozzle, and we have a coat of paint.
Typically we will take a bottle of soda or aerated drinks, we slowly turn the cap and allow the air to gradually escape before completely removing the lid. We do this because we’ve learned over time that popping it open too fast causes it to fizz up and spill all over us and everything around us.
Microscopic view of a gas. Microscopic view of a liquid. Microscopic view of a solid.
•Gasses:-Are well separated with no regular arrangement. -Vibrate and move freely at high speeds.
•Liquids:-Are close together with no regular arrangement. Vibrate, move about, and slide past each other.•Solids:-Are tightly packed, usually in a regular pattern. -Vibrate (jiggle) but generally do not move from place to place.
A plasma is the fourth state of matter and is a hot ionized gas consisting of approximately equal numbers of positively charged ions and negatively charged electrons. The characteristics of plasmas are significantly different from those of ordinary neutral gases so that plasmas are considered a distinct "fourth state of matter." For example, because plasmas are made up of electrically charged particles, they are strongly influenced by electric and magnetic fields (see figure) while neutral gases are not. An example of such influence is the trapping of energetic charged particles along geomagnetic field lines to form the Van Allen radiation belts.
The state or phase of matter depends on its temperature and the surrounding pressure. We typically see materials change their state at normal atmospheric pressure.Changing the surrounding pressure changes the temperature at which a material goes from one state to another. The reason is because the molecules causing the pressure inhibit the molecules of the material. Graphs have been made comparing the values of temperature and pressure needed to have a change of state of various materials. They show special situations where a solid will change directly into a gas, skipping the liquid phase.Materials expand or contract with the change in pressure and temperature.
The temperature that a material changes its state is usually given at the average air pressure at sea level. For example, water will boil at 100o C (212o F) at sea level. But if the pressure is changed, the temperature at which the material changes its state also changes. The higher the pressure, the higher the temperature needed to change the state of the material.Pressure of surrounding materialThis pressure can be air pressure, water pressure or pressure from some other material surrounding the object. Usually it is fluid pressure, but it can be pressure from a solid if the object is completely encased in the solid.Molecules inhibit changesThe reason increasing pressure will increase the required temperature of changing the state is because the pressure is a result of molecules from the outside material (like air molecules for air pressure) smashing into the object's molecules and preventing them to become free from their own molecular attraction.The surrounding pressure helps the molecular attraction overcome the kinetic energy of the material's molecule or atoms.
•A change in the surrounding pressure can change the temperature that will cause a material to go from one state to another. This is because the molecules causing the pressure inhibit the molecules of the material. A graph comparing the values temperature and pressure needed to have a change of state of various materials also shows special situations where a solid will change directly into a gas. Materials expand or contract with the change in pressure and temperature.
•Increased pressure will contract gases. The effect of pressure on liquids and solids is considerably less and in some cases considered negligible. On the other hand, most substances expand when heated and contract when cooled. This continues even after they have changed their states.
•Pressure is a measurement of the force per unit area. Fluid pressure can be caused by gravity, acceleration, or forces in a closed container. Since a fluid has no definite shape, its pressure applies in all directions. Fluid pressure can also be amplified through hydraulic mechanisms and changes with the velocity of the fluid.
