Physical Science What is matter? Matter: anything that has mass and takes up space Matter is made up of extremely tiny particles called atoms and molecules. Atoms and molecules make up the three common states of matter on Earth 1) solids 2) Liquids 3) gases Solids Solids: Has a definite shape and a definite volume They do not take the shape of their container because they do not have enough energy Particles of solids are tightly packed, vibrating about a fixed position. Examples: Wood, rock, plastic Liquids Liquids: Has a definite volume and does not keep its shape Takes the shape of the container because the particles have enough energy to move out of their fixed position by not enough energy to move apart. Particles of liquids are tightly packed, but are far enough apart to slide over one another. Examples: water, alcohol, vegetable oil Water properties activity Procedure 1. Use a dropper to gently squeeze out one drop of water but try not to let the drop fall completely out of the dropper. See how far you can make the drop hang off the end of the dropper without the drop falling. 2. Place 4 or 5 drops of water together on the wax paper to make a medium-size drop. 3. Gently tilt the wax paper in different directions so that the drop moves. 4. Use a popsicle stick to slowly move your drop around the wax paper. Try using your popsicle stick to separate your drop into two. 5. Use your popsicle stick to move the two drops near each other. Then move one drop so that the two drops touch. Viscosity Viscosity: a liquid's resistance to flow the slower a liquid flows, the higher the viscosity The viscosity results from the strength of the attraction between the particles Viscosity increase as the liquid becomes colder Example: Honey has higher viscosity than water Surface Tension Surface Tension: The uneven forces acting on the particles on the surface of a liquid. attractive forces causes particles to pull together and resist pulling apart. Ex. Water spider moving on the surface of a pond Water has surface tension Water molecules are held together by hydrogen bonds Water balloon video www.middleschoolchemistry.com/multimedia/chapter1/lesson1 #water_balloon Why do you think the water keeps its shape the moment the balloon is popped? water holds together pretty well because the water molecules are attracted to each other. Imagine a drop of water hanging from your finger. How is this similar to the water staying together after the balloon is popped? water molecules are very attracted to each other by hydrogen bonds Play water drop unite 1.1 Surface Tension lab Gases Gases: Does not have a definite shape or volume Move at high speed in all directions Particles of gases are very far apart and move freely Can expand or be compressed Examples: Carbon Dioxide, Oxygen, Helium Changes of state Temperature: The average kinetic energy of the individual particles Heat: The movement of thermal energy from a substance at a higher temperature to one at a lower temperature. Heat Loss: When a substance looses heat and energy; results in a change of state of matter Heat Gain: When a substance gains heat and energy; results in a change of state of matter Affects of temperature on solid matter Ring and Ball demo Materials for the Demonstration • Ball and ring designed specifically for this demonstration] • Bunsen burner for heating the ball • Room-temperature water (to cool the ball) Demo : www.middleschoolchemistry.com/multimedia/chapter1/less on4#heating_cooling_metal_ball Draw a model of the atoms in the metal ball at room- temperature and after it has been heated. Use circles and motion lines to show the speed and spacing of the atoms in the roomtemperature ball. Include captions like “atoms faster and further apart” or “atoms slower and closer together” to describe your drawings Affects of temperature on solid matter In a solid, the atoms are very attracted to one another. The atoms vibrate but stay in fixed positions because of their strong attractions for one another. Heating a solid increases the motion of the atoms. An increase in the motion of the atoms competes with the attraction between atoms and causes them to move a little further apart. Cooling a solid decreases the motion of the atoms. A decrease in the motion of the atoms allows the attractions between atoms to bring them a little closer together. Affects of temperature on liquid matter Is the speed of water molecules different in hot and cold water? Materials Hot water in a clear plastic cup Cold water in a clear plastic cup Food coloring (yellow and blue) 4 droppers 1) Describe what the colors looked like and how they moved and mixed in the cold water. In the cold water, the yellow and blue colors drifted and slowly swirled and spread a bit but were in streaks. The colors didn’t mix very much. 2) Describe what the colors looked like and how they moved and mixed in the hot water. In the hot water, the colors spread more quickly and mixed together more than in the cold water. The water turned greener in the hot water than it did in the cold water. 3) What does the speed of the mixing colors tell you about the speed of the molecules in hot and cold water? Since the colors moved faster in the hot water, it means that the water molecules in the hot water move faster than the molecules in cold water. www.middleschoolchemistry.com/multimedia/chapter1/lesson2#hea ting_and_cooling Affects of temperature on gaseous matter Heating and cooling affect balloon Materials Balloon Water bottle plastic container filled with water ice and hot water Molecules of gas: Why does the balloon inflate when the bottle is placed in the hot water? because the molecules that make up the air inside the bottle moved faster. These molecules hit the inside of the bottle and balloon harder and more often. They pushed against the balloon hard enough that it was able to overcome the outside air pressure and made the balloon grow. 2) Why does the balloon deflate when the bottle is placed in the cold water? because the molecules that make up the air inside the bottle moved slower. These molecules hit the inside of the bottle and balloon less often and with less force. The outside air pressure pushed harder on the outside of the balloon than the molecules pushed from the inside so the balloon got smaller. 1) Heat Transfer Conduction Convection Materials: Solids and liquids Materials: Gases and Heat Flow: Direct contact Liquids Heat Flow: Warm air rises, cool air sinks (convection currents). Indirect contact Example: Air Currents between heat source and matter Examples: Metal spoon in water-heats fast Wooden spoon in waterheats slow Heat Transfer Radiation Materials: Travels through a vacuum (absence of air) Heat Flow: Travels in waves Example: Sunlight travels through space (through a vacuum) then energy is absorbed by earths atmosphere (air) and the objects on earth Which one are you seeing? Heat Transfer Radiation Materials: Travels through a vacuum (absence of air) Heat Flow: Travels in waves Example: Sunlight travels through space (through a vacuum) then energy is absorbed by earths atmosphere (air) and the objects on earth Which one are you seeing? A B C Phase Change When matter changes from one form to another Phase change depends on the heat/energy of particles When a change of state occurs, energy is either lost to other matter, or gained by other matter. Energy can be transferred from one object to another but it can NEVER be destroyed (The law of conservation of energy) Type of phase change Melting Freezing Boiling Vaporization Evaporation Condensation Sublimation Deposition Change Heat (+ or -) Type of phase change Change Melting Solid to Liquid Freezing Boiling Vaporization Evaporation Condensation Sublimation Deposition Heat (+ or -) + Type of phase change Change Melting Solid to Liquid + Freezing Liquid to Solid - Boiling Vaporization Evaporation Condensation Sublimation Deposition Heat (+ or -) Type of phase change Change Melting Solid to Liquid + Freezing Liquid to Solid - Boiling Liquid to Gas + Vaporization Evaporation Condensation Sublimation Deposition Heat (+ or -) Type of phase change Change Melting Solid to Liquid + Freezing Liquid to Solid - Boiling Liquid to Gas + Vaporization Liquid to Gas + Evaporation Condensation Sublimation Deposition Heat (+ or -) Type of phase change Change Melting Solid to Liquid + Freezing Liquid to Solid - Boiling Liquid to Gas + Vaporization Liquid to Gas + Evaporation Liquid to Gas + Condensation Sublimation Deposition Heat (+ or -) Type of phase change Change Melting Solid to Liquid + Freezing Liquid to Solid - Boiling Liquid to Gas + Vaporization Liquid to Gas + Evaporation Liquid to Gas + Condensation Gas to Liquid - Sublimation Deposition Heat (+ or -) Type of phase change Change Melting Solid to Liquid + Freezing Liquid to Solid - Boiling Liquid to Gas + Vaporization Liquid to Gas + Evaporation Liquid to Gas + Condensation Gas to Liquid - Sublimation Solid to Gas + Deposition Heat (+ or -) Type of phase change Change Heat (+ or -) Melting Solid to Liquid + Freezing Liquid to Solid - Boiling Liquid to Gas + Vaporization Liquid to Gas + Evaporation Liquid to Gas + Condensation Gas to Liquid - Sublimation Solid to Gas + Deposition Gas to Solid - Phase change Vaporizes Evaporates Water Freezing point: 0°C Melting point: ___ 0°C _ Boiling point: _____100 °C______ Absolute Zero -The lowest possible temperature; when molecules can no longer move. The basis for the Kelvin scale (0 Kelvin means all motion/energy stops). But what happens if you raise the temperature to super-high levels… between 1000°C and 1,000,000,000°C ? Will everything just be a gas? STATES OF MATTER PLASMA A plasma is an ionized gas (remove electron) A plasma is a very good conductor of electricity and is affected by magnetic fields. Plasmas, like gases • Plasma is the have an indefinite common state shape and an of matter indefinite volume. STATES OF MATTER SOLID Tightly packed, in a regular pattern Vibrate, but do not move from place to place LIQUID Close together with no regular arrangement. Vibrate, move about, and slide past each other GAS Well separated with no regular arrangement. Vibrate and move freely at high speeds PLASMA Has no definite volume or shape and is composed of electrical charged particles Some places where plasmas are found… 1. Flames 2. Lightning 3. Aurora (Northern Lights) The Sun is an example of a star in its plasma state Lab Groups When you go to your station, you will need everything (we will be going back to notes while you are there) Be as neat as possible at your station. The first demo lab we will do is the evaporation lab. Changes of state Evaporation: Does adding heat (energy) or making something cold increase evaporation? Do evaporation lab demo Materials for each group 3 quart-size zip-closing plastic storage bags Hot water (about 50 °C) Room-temperature water Cold ice water 3 squares of brown paper towel 3 droppers Evaporation Evaporation occurs when molecules in a liquid gain enough energy that they overcome attractions from other molecules and break away to become a gas. Adding energy increases the rate of evaporation. Ex. Adding heat Evaporation video http://www.middleschoolchemistry.com/multimedia/chapter2/lesso n2 Water molecules http://www.middleschoolchemistry.com/multimedia/chapter2/lesso n2 Condensation Question to investigate Does making water vapor colder increase the rate of condensation? Materials for the demonstration 2 tall rimmed clear plastic cups 2 tall smaller-rimmed clear plastic cups Room-temperature water Hot water (50 °C) Ice cubes Gallon-size zip-closing plastic bag Condensation on a cup video http://www.middleschoolchemistry.com/multimedia/chapter2/lesson3 Condensation Condensation is the process in which molecules of a gas slow down, come together, and form a liquid. When gas molecules transfer their energy to something cooler, they slow down and their attractions cause them to bond to become a liquid. Condensation video: http://www.middleschoolchemistry.com/multimedia/chapter2/lesso n3 Making water vapor colder increases the rate of condensation. Increasing the concentration of water vapor in the air increases the rate of condensation. Condensation Show the animation Evaporation & Condensation http://www.middleschoolchemistry.com/multimedia/cha pter2/lesson3 Examples: Water vapor on a cup Fog Moisture on a car window Dew Clouds The fog that comes from your mouth on a cold day Freezing Freezing is the process that causes a substance to change from a liquid to a solid. Freezing occurs when the molecules of a liquid slow down enough that their attractions cause them to arrange themselves into fixed positions as a solid. Show the movie Ice Can http://www.middleschoolchemistry.com/multimedia/cha pter2/lesson4 Show the movie Ice Bomb http://www.middleschoolchemistry.com/multimedia/ch apter2/lesson4 Melting Melting is a process that causes a substance to change from a solid to a liquid. Melting occurs when the molecules of a solid speed up enough that the motion overcomes the attractions so that the molecules can move past each other as a liquid. Show students the video Ice Melting on Different Surfaces. www.middleschoolchemistry.com/multimedia/chapter2/lesson5#ice_melti ng_on_different_surfaces Show the animation Melting Ice. www.middleschoolchemistry.com/multimedia/chapter2/lesson5#melting_i ce Ice versus Water Ice is an orderly crystal structure Water molecules in ice vibrate but don’t move past each other. Ice Water Ice versus Water As the temperature increases water molecules begin to vibrate more. Eventually their movement overcomes their attractions and they can no longer stay in their orderly crystal structure. Ice versus Water As the ice melts, the orderly arrangement collapses and the water molecules move past each other and actually get closer together as liquid water. Ice on a can http://www.middleschoolchemistry.com/multimedia/chapter2/lesson4 Sublimation Does all ice melt the same?? Dry ice is frozen carbon dioxide gas. Carbon dioxide gas must be very cold in order to become a solid (about –78 °C or –109 °F). Video-Dry Ice http://www.middleschoolchemistry.com/multimedia/chapter2/lesso n5 Sublimation occurs when molecules of a solid move fast enough to overcome the attractions from other molecules and become a gas. Video-Ice bomb http://www.middleschoolchemistry.com/multimedia/chapter2/lesson5 Since frozen carbon dioxide never becomes a liquid under normal pressure, it is called dry ice. Deposition Gas turns into a solid Ex. Frost Video of a snowflake forming at http://www.its.caltech.edu/~atomic/snowcrystals/movies /movies.htm