Physical Science Chapter 14 test
Archimedes
(287-212 BCE) Greek mathematician and inventor who made a discovery about buoyancy
Explain why a hot-air balloon descends when the burner is turned off while the balloon is in the air.
. A hot air balloon is able to float because of Charles's law. Charles's law says if the temperature increases, the volume increases when the pressure is constant. A hot air balloon's material is flexible, so the pressure balances on the inside and the outside. When the temperature of the burner increases, the volume also increases, allowing it to float.
The Kinetic theory
1. all matter is composed of tiny particles (atoms, molecules, and ions) 2. these particles are in constant, random motion 3. the particles collide with each other and with the walls of any container in which they are held. 4. the amount of energy that the particles lose from these collisions is negligible.
State the basic assumptions of the kinetic theory.
1. matter is composed of tiny particles 2. these particles are in constant, random motion 3. the particles collide with each other and with the walls of any container 4. the amount of anergy that the particles lose from these collisions is negligible (small)
viscosity
A liquid's resistance to flowing high viscosity- flows slowly low viscosity- flows fastly ex: refrigerated syrup has a high viscosity, it flows slowly heated syrup has a low viscosity, it flows faster TIP= high- thicker nonflowy low- thinner flowy
Crystalline
A solid that is made up of crystals in which particles are arranged in a regular, repeating pattern example- the geometric arrangement of ice (hydrogen and oxygen atoms have a pattern)
Predict, using Boyle's law, what will happen to a balloon that an ocean driver takes to a pressure of 202 kPa.
As the ballon goes under water, the pressure increases. When the pressure increases, the volume decreases. (Boyle's law) The ballon will eventually pop, under so much pressure.
What does temperature represent?
Average kinetic energy of molecules
Compare and contrast evaporation to boiling.
Boiling is a way a liquid can vaporize. Boiling differs from evaporation because it occurs throughout the liquid at a specific temperature. Boiling depends on the pressure on the surface area. Evaporation differs from boiling because it occurs at the surface of a liquid and can happen at almost any temperature. Particles must be at the liquid's surface and have enough kinetic energy to escape the attractive forces of the liquid to evaporate.
pressure formula
Force (N) / Area (m2) P= F/A F= PA A= F/P
Blaise Pascal
He was a French mathematician who developed the "Pascaline." He discovered that pressure applied to a fluid is transmitted throughout the fluid.
vaporization (evaporation and boiling)
Liquid to gas when particles move fast enough to escape the attractive forces of other particles they enter a gas state and can occur in 2 ways evaporation- occurs at the surface of a liquid and happens at nearly any temperature, particles must be at the surface and have enough kinetic energy to escape the attractive forces boiling- occurs throughout the liquid at a specific temperature, depending on the pressure on the surface of the liquid
What is pressure measured in?
Pascals (Pa)
Describe the movement of the particles in solids, liquids, and gases.
Solid= particles are tightly packed and locked, unable to move Liquid= particles are touching and close together, but are all to slide, move, and flow past each other Gas= particles move fast and are spread apart from each other
thermal energy
The total energy of motion in the particles of a substance including kinetic and potential energy energy from the motions of individual particles and energy from forces that act within or between particles are both forms of thermal energy
Pascal principle
When force is applied to a fluid, it is transmitted equally to all parts throughout the fluid example- squeezing a bottle of mustard squeezing toothpaste pressure in= pressure out example: hydraulic lifts use pascal's principle to lift heavier objects
Scuba divers often wear buoyancy vests to maintain neutral buoyancy, so they neither sink to the bottom or float to the surface. If the dive takes a breath the diver will rise slightly. When the diver exhales, the diver will sink slightly. Explain why this happens.
When scuba divers take a breath and slightly rise, this is because oxygen is less dense than water. When a scuba diver takes a breath out a slightly sink, the oxygen goes out of the lungs, causing the diver to sink. When the diver takes breaths in through the lungs, the air inside wants to rise above the water.
Robert Boyle
a British scientist who is father of modern chemistry, who found Boyle's law
Jaques Charles
a French scientist who Discovered the relationship between the volume and temperature of a gas charles's law
Daniel Bernoulli
a Swiss scientists who studied the properties of moving fluids like water and air
Boyle's law
as the volume is decreased, the pressure increases when the temperature is constant by increasing pressure, you decrease the volume into a smaller area ex: squeezing a balloon to pop it Pressure and volume are inversely related When you add pressure, the space gets smaller and the volume is decreased. Therefore there are more collisions of particles. (gases and air law)
heating curve of water
below 0 -40... solid 0-100- Liquid (melts at 0) 100-140...gas (boils at 100) shows the temperature of water in its three states as heat is added or removed at fixed areas phase change is constant
Bernoulli's principle
fluid velocity/speed increases when the flow of the fluid is restricted as the velocity increases, the pressure exerted by that fluid decreases fast moving air= low pressure slow moving air= high pressure example- placing your thumb on a water hose spout, the water sprays out faster hose end sprayer
How would the heating curve for glass be different from the heating curve of water?
glass= heating curve becomes soft and susceptible as the temperature increases, lacks the repeating crystalline structure of solids like ice or water Water= can have a high boiling point because of the strong hydrogen bonds DURING THE PHASE CHANGE, THE TEMPERATURE REMAINS CONSTANT
heat of vaporation
how much energy it takes to change phases from a liquid to a gas
heat of fusion
how much energy it takes to change phases from a solid to a liquid
Boyle's law equation
initial pressure * initial volume= final pressure * final volume P1V1=P2V2
charles's law equation
initial volume=final volume/initial temperature= final temperature V1 V2 ____ = ____ T2(K) T2(K) temperature must be measured in kelvins
condensation
liquid to gas the reverse of vaporization water which collects as droplets on a cold surface when humid air is in contact with it
liquid crystals
liquids which keep some ordered structure a most substances do, acts like a solid two classes of materials that do not react as you would expect when they are changing states ex: liquid crystal displays for phones, calculators, and net books, (dad's computer displayer) LIQUID
density
mass/unit volume
Kilopascal (kPa)
most pascals are given in kilopascals because 1 Pa is a very small amount of pressure
What is the air around a person composed of?
nitrogen, water, oxygen, and other gases
Describe how the particles of a substance behave at its boiling point.
particles behave by not being able to escape, due to the external pressure pushing down on the liquid
Describe how the particles of a substance behave at its melting point.
particles slip out of order arrangement of a solid because of the energy required to melt (heat of fusion)
Heating curves
shows how temperature changes over time as thermal energy is continuously added 1. energy is put in to overcome the attractive forces between the particles 2. once overcame the particles move freely and temperatures increase
Using the graph in Figure 7 describe the energy changes that are occurring when water goes from -15C to 120C.
shows when he thermal energy is continuously added, the temperature increases
If you blow up a balloon, tie it off, and release it, it will fall to the floor. Why does it fall instead of float? Explain what would happen if the balloon contained helium instead of air.
the ballon filled up with air weighs more than the air and therefore does not float. helium is lighter than air, and the balloon floats when filled with helium, helium is less dense and greater has a buoyancy
Archimedes' Principle
the buoyant force on an object is equal to the weight of the fluid displaced by the object ex: a block of wood placed in water sinks as water continues to push out only until it equals the block's weight when the weight of the water displaced is equal to the block's weight, it floats if the weight of the water displaced is less than the weight of the block, it sinks
Explain plasma
the fourth familiar state of matter, a state of matter beyond the gas state the atoms that make up plasma collide with such force that the electrons are completely stripped off the atoms most universe objects are in the plasma state
Describe what would happen to the volume of a gas if the pressure on it were decreased and then the gas's temperature were increased.
the gas would expand
Describe how fluids exert forces on objects?
the molecules in the fluid that collide with the surfaces of the object in the fluid bounce on in all directions of the object buoyancy
Explain why squeezing a plastic mustard bottle forces mustard out the top.
the mustard comes out because of the force applied to it, making mustard to flow out
amorphous solids
the particles are not arranged in a regular pattern two classes of materials that do not react as you would expect when they are changing states ex: butter gradually turns into a liquid over a range of temperatures SOLIDS
Explain why a steel boat floats on water but a steel block does not
the steel block has a greater surface area and has less density now then the water, making it float the steel block has more density than the water and sinks
Charles's law
the volume of a gas increases with increasing temperature when the pressure is constant when a gas is heated, its particles move faster and its temperature increases and begin to strike the walls of they container with more force ex: heated water in a can, steam comes out, and immediately put it in cold water, the can begins to contract/ cripple because of the rapid phase change temperature and volume are directly proportional WHEN HEATED, TEMPERATURE RISES, THE SPACE EXPANDS, THUS THE VOLUME EXPANDS AND THE PARTICLES MOVE FASTER, HITTING AGAINST THE WALLS OF THE CONTAINER. WHEN COOLED, VOLUME DECREASES AND THE TEMPERATURE DECREASES, PARTICLES MOVE SLOWER.
Describe the particles in a solid
they are closely packed together, and are in little motion. has little kinetic energy that the particles are unable to overcome their attractions to each other has a definite shape and volume
Describe the particles in a liquid
they are constantly moving and slide past each other because the particles have less kinetic energy, they are less able to overcome their attractions with each other and cling together liquid has a definite volume
Describe the particles in a gas
they are in constant, random motion quickly and collide with each other and the walls of their container gases don't have a fixed volume or shape they are spread out has the most kinetic energy, since its particles are always moving fastly in constant motion
Explain water and thermal expansion
water expands as the temperature decreases because of the negative and positive charges in the water molecules line up so only positive and negative areas are near each other, leaving gaps the water starts to expand at 4C to 0C and becomes less than liquid water this is why ice floats on liquid water
Describe, using Bernoulli's principle, how roofs are lifted off buildings in tornados.
when the wind has a high velocity and rate of speed, a low pressure area is above the roof, causing the roof to fly off, the house pushes the roof, the pressure underneath lifts it up
Explain thermal expansion
when thermal energy is transferred to a concrete sidewalk, it expands, with no seams it would crack in hot weather it expands in hot weather because particles move faster and faster apart as temperature rises an results in an expansion objects contract when they cool concrete sidewalk with seams example: seams in concrete thermometers (as the temperature rises, the thermometer liquid rises) hot air balloons Opposites= water, water expands as temperature decreases
