Physical ScienceChapter 16: Solids, Liquids, and

Gases

There are 4 different states of matter:

• A. Solid

• B. Liquid

• C. Gas

• D. Plasma

Kinetic Theory of Matter• All matter is made of tiny particles (atoms or

molecules) which are in constant motion.

• How tightly these particles are packed together and how strongly they are bonded will determine what state of matter the material is.

• Think of it like a snowball. The more tightly you pack it, the more strongly the flakes (particles) are bonded together. Pack it loosely, and the flakes are more likely to fly apart (loosely bonded).

• Also, particles vibrate more or move around more quickly if the matter is heated up. Conversely they also slow down as they are cooled.

• Adding and removing heat is the #1 way to change a material from 1 state of matter to another. (we’ll talk about this later)

• What is the relationship between the temperature of the particles and their rate of movement or vibration?

Solids

• Have a definite shape and a definite volume

• Particles are tightly packed and are bonded together relatively strongly

• Diamonds form under tremendous pressure, and therefore their particles (carbon atoms) are packed very tightly. This is one reason why diamonds are so hard.

Crystalline and Amorphous Solids

• The particles of many solids are arranged in definite repeating patterns. These are called crystalline solids.

• Gemstones, minerals like salt, and safety glass are all examples of crystalline solids. They have a predictable pattern of particles.

• Amorphous solids have no definite structure or arrangement of their particles.

• These materials will break in an unpredictable manner, with no pattern.

• Examples include plastics, glass, and wax.

Liquids• Have a definite volume, but no definite shape

(they take the shape of their container)

• Particles move around freely within the liquid.

Viscosity in fluids• Viscosity is the property of a fluid which

describes how well it will flow

• Low viscosity flows easily, high viscosity is much thicker.

Gases

• Gases have no definite volume and no definite shape (but do have mass). They simply take the shape of the container they are in.

• Gas particles are very loosely bonded and move around freely.

• Gases, unlike solids and liquids, are fairly easy to compress and also readily expand. That is why we say they have no definite volume.

• Expansion and contraction of gases explains why warm air rises and cold air sinks.

• Why does it hurt more to jump onto a water bed than on an air mattress?

• Plasma, the 4th state of matter, is the most common state of matter in the universe. It is a gas-like mixture of positive and negatively charged particles.

These particles make plasma a high energy state of matter.

• A plasma TV has a large number of tiny cells containing xenon and neon gases. When an electric current is passed through these individual cells, they give off energy which causes phosphors inside the cell to give off light. These tiny lights combine together to produce an image.

Changes of state

• By adding or removing thermal energy from a sample of matter, it is often possible to cause it to change from one state of matter to another.

Melting and Freezing

• Adding thermal energy can change some materials from a solid to a liquid (melting)

• Removing thermal energy may change some materials from a liquid to a solid (freezing)

• Let's say an ice storm knocks out your power so you light some candles.

As the melted wax drips off, it solidifies as it cools. Is this considered freezing?

Condensation & Evaporation

• Changing a gas to a liquid is called condensation (loses heat)

• Ex.: breathing on a cold window, warm air rising and forming clouds, droplets on a cold glass, dew

• Evaporation is where a liquid changes to a gas (gains heat).

• Ex.: steam rising from a hot liquid, sweat cooling your body, a steam locomotive

• Is boiling the same as evaporation?

• How do the bubbles magically appear in a pot of boiling water?

Sublimation• Changing a solid directly to a gas is called

sublimation.

• Examples: dry ice, frost on a window

• This is why you don’t make dry ice bombs!

Thermal ExpansionThermal Expansion

The volume of an object will The volume of an object will increase as it's temperature increase as it's temperature increases, and vice versa increases, and vice versa (directly proportional)(directly proportional)

Examples of thermal expansion:

Shrink Fitting

Laws and PrinciplesLaws and Principles

Boyle's Law - for a gas at a constant temperature, if you increase the pressure on the gas, the volume will decrease, and vise versa (ind. prop.)

Ex.: -step on a Pringle's can

-squeezing a balloon

A whoopie cushion utilizes Boyle’s Law.

Charle's Law• For a gas at a constant pressure, if you

increase the temperature, then the volume will increase, and v/v.

• Ex.: Hot air balloon, car tires

• Charles Law is similar to what other concept which we have discussed this chapter?

Pascal’s Principle• Pascal’s Principle states that pressure exerted

on a fluid is transmitted equally throughout the fluid.

• As a downward force is applied to the piston, the increased pressure is transmitted throughout the entire system.

P = F/A and P = F/A

10 Pa = 50 N/5 m2 and 10 Pa = 500N/50 m2

Examples: -squeezing a tube of toothpaste

-The Blob

-Pressurizing the cabin of an airplane

• Carlos made a balloon rocket as shown in the picture. According to Pascal’s Principle, what would happen if the rocket had an opening on both ends instead of just the one. Explain.

Bernoulli's Principle

• If you increase the speed of a fluid moving over the surface of a material, the pressure will decrease as a result (i.e. fluid velocity and pressure are indir. prop.)

• Ex.: Airplane wing, frisbee, fan blade, treading water

Venturi Effect• If a moving fluid is forced to travel in a

narrower path, the velocity of that fluid will increase

• Ex.: Spitwad, nozzle on hose, sand blasting

Archimede's Principle• The buoyant (upward) force on an object

submerged in a fluid is equal to the weight of the fluid displaced by that object.

• Buoyancy is the ability of an object to rise or float in a fluid.

• Ex.: underwater handstand, lifting a submerged rock, finding your weight in a vacuum.

• Let’s say you accidentally fill your bathtub all the way full. So you know when you get in, some of the water will have to overflow.

• If you were to collect all of the water that overflowed and weigh it (in Newtons), then that would be the amount of buoyant force pushing up on you in the tub.

• So if you weight 668 N (about 150 pounds), and the water which you caused to overflow (displaced) weighed 620 N (about 139 pounds), then your weight as you sit in the tub would be about 48 N (11 pounds), if you were sitting on a scale on the bottom of the tub.

Buoyant Force - Weight _______________________

Net Force

• So if you lifted a 200 pound rock underwater, which displaced 160 pounds of water, how much it would make the rock seem to weigh?

• Larry is driving down the interstate, and pulls out into the left-hand lane to pass a semi. When he gets right alongside the semi, he notices a strong force seeming to pull him toward the truck. The force disappears once he is past the truck.

What produced this force?

• Mark is not real bright. In an attempt t blow out the candles on his birthday cake, he reasoned that the more air he could expel, the more likely the candles are to go out. So he opened his mouth as wide as possible, and blew. Problem?

• Carl is going to take a hot bath after a hard practice. He noticed that the bar of soap he put in the tub sank to the bottom, but when he added a lot of epsom salt to the water (used to relieve muscle aches), the soap slowly floated to the top. Explain why this happened.

• Helicopters produce lift by forcing air to move over their angled blades. This creates a low pressure area over the top of the blades, allowing the copter to rise.

• Recent technology, however, has allowed designers to create helicopters which can fly upside down. How could that happen?

• Bud chugs a bottle of Pepsi. He knows that he may belch some after doing this because of the carbonation in the soda. However, he continues to belch on and off for the next 10 min. How could such small bubbles produce so much belching?

1. As a hot air balloon rises higher in the atmosphere, the balloon itself will gradually grow smaller, and as a result support less weight.

2. A salvage ship is using a large crane to lift the hull of a sunken ship out of the ocean. The ship is able to lift the hull to the surface, but is unable to lift it any further above the water.

Iron is much denser than water, yet Bob claims to have discovered a way to make iron float in water without attaching anything to the iron to help keep it afloat. Hmmm…….

• The rear opening on a jet engine where the hot gases are expelled is usually tapered, or narrower than the rest of the engine. Why do you think this is so?

Why were the planners so sure that everything would be ok?

• For an outdoor wedding, the wedding planners inflated the balloons the day before and put them in place. When they came in the next morning, the balloons were half flat. “Don’t worry” the planners told the family, “the balloons will be fine when the ceremony starts this afternoon.”

• As a river flows from left to right as shown below, which way will the water move through the off-chute (A), clockwise or counterclockwise? Why?

A bathtub is filled to the brim with water, and a large chunk of ice floating in it. If the ice were to melt, would the water level in the tub raise, lower or stay the same?

Explain why, using a law or principle.

• Some bread doughs come in sealed tubes which require the user to twist the tubes in order to pop them open. Which law or principle explains why this occurs?

• As you prepare to go scuba diving, you have 2 tanks, one full of compressed air and the other one empty. However, you don’t know which is which, so you toss them both into the water to see. What will be the difference, and why?

• A hydrofoil is a watercraft designed to ride up out of the water when it reaches high speeds. How is this accomplished, and why?

If a passenger jet were to suddenly have a window break out, materials inside would immediately start to get “sucked” out of the window. Explain why this would happen, using one of the laws or principles we have discussed.

Carl found that if he squeezed the sides of his juice box, the liquid would shoot up out of the straw. Explain why.

• Many people think that oxygen gas is flammable, and that is why oxygen tanks have a warning label on them cautioning people that they are combustible. What is the real reason they have this warning?

1. According to Archimedes’ Principle, the buoyant (upward) force exerted on an object submerged in a fluid is equal to the weight of the fluid displaced by the object. With this being the case, explain why it is easier to float in salt water than pure water.2. If a passenger jet were to suddenly have a window break out, materials inside would immediately start to get “sucked” out of the window. Explain why this would happen, using one of the laws or principles we have discussed.3. As the gym bleachers were being put up, a basketball accidentally got caught behind them and was popped. Explain how this occurred using one of the laws or principles we have discussed.4. Lenny turned on his front porch light (outside light) one morning when it was extremely cold outside. After about 30 sec., the glass of the bulb broke. Explain why.

5. A steamroller applies a force of 6,900 N over an area of 3 m2. How much pressure is it creating?6. State the Venturi Effect and give 2 examples.

1.2.

7. Helium tanks are often used to inflate balloons. The tanks usually will have a warning label which gives a particular temperature range in which they are to be stored. Explain why.8. Carl found that if he squeezed the sides of his juice box, the liquid would come up out of the straw. Explain why.