Middle+School+Chemistry+Chapter+2

=Phases of Matter= = = =Chapter 2, Lesson 1: Heat, Temperature, and Conduction= media type="custom" key="24074668" media type="custom" key="24075222"

Key Concepts
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 * Adding energy (heating) atoms and molecules increases their motion, resulting in an increase in temperature.
 * Removing energy (cooling) atoms and molecules decreases their motion, resulting in a decrease in temperature.
 * Energy can be added or removed from a substance through a process called conduction.
 * In conduction, faster-moving molecules contact slower-moving molecules and transfer energy to them.
 * During conduction the slower-moving molecules speed up and the faster-moving molecules slow down.
 * Temperature is a measure of the average kinetic energy of the atoms or molecules of a substance.
 * Heat is the transfer of energy from a substance at a higher temperature to a substance at a lower temperature.
 * Some materials are better conductors of heat than others.

Objective
Students will be able to describe and draw a model, on the molecular level, showing how energy is transferred from one substance to another through conduction.

Materials Needed

 * 2 sets of large metal washers on a string
 * Styrofoam cup filled with hot water
 * room-temperature water
 * thermometer
 * graduated cylinder
 * large tea pot


 * 1) Complete the procedure as outlined on your activity sheet. Record your answers.
 * 2) Watch the following videos:media type="file" key="heating_washers.wmv" width="300" height="300" media type="file" key="cooling_washers.wmv" width="300" height="300"
 * 3) Watch the following animations and record your observations on your activity sheet: media type="file" key="heated_spoon.swf" width="360" height="270" media type="file" key="cooled_spoon.swf" width="360" height="270"
 * 4) In your science notebook, describe how the process of conduction caused the temperature of the washers and water to change in the activity.
 * 5) What is conduction? Put your answer in your notebook.
 * 6) Look at the following illustrations: Spoon in Hot Water Before and After & Hot Spoon in Room Temp Water Add motion lines to the "after" illustration and add descriptive words to the drawing on your activity sheet.
 * 7) View the following animation: Temperature Place the temperature slider at about the middle of the range, to add energy move the slider about 2/3 of the way to the right.
 * 8) Complete the "Take It Further" portion on your activity sheet. Watch this animation and watch the motion of the molecules in the metal, cardboard, and in the finger. media type="file" key="conducting_energy.swf" width="360" height="270"

=Chapter 2, Lesson 2: Changing State - Evaporation= media type="custom" key="24075288" Evaporation and Condensation

Key Concepts

 * 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
 * To conduct a valid experiment, variables need to be identified and controlled

Objective
Students will be able to identify and control variables to design a test to see if heating water affects the rate of evaporation. Students will be able to explain, on the molecular level, why adding energy increases the rate of evaporation.

Materials Needed

 * 2 quart-size zip-closing plastic storage bags
 * hot water
 * room temperature water
 * 2 square of brown paper towel
 * 2 droppers
 * 6 Styrofoam balls (1 1/2-inch)
 * 12 Styrofoam balls (1-inch)
 * 2 flat toothpicks
 * school glue
 * permanent marker


 * 1) Dampen one of the brown paper towels with water so that the color appears darker than the dry piece of paper towel. Feel the difference between the two pieces. Note your observations in your science notebook. Predict if you think the towel will be dry by the end of this lesson. When water evaporates, where do the water molecules go?
 * 2) Test the evaporation of just 1 drop of water on a brown paper towel. What could you do to make a small amount of water evaporate faster from a paper towel? Complete the procedure on your activity sheet. Record your observations.
 * 3) Watch the following animation: media type="file" key="evaporation.swf" width="360" height="270"
 * 4) View the following & then describe your observations on your activity sheet: Heating and Evaporation
 * 5) Watch the following animations: Models of Water Molecules, Liquid Water, & Water Vapor
 * 6) Make 6 space-filling models of water molecules using Styrofoam balls. Follow the procedure on your activity sheet.
 * 7) Complete the Take It Further section on your activity sheet

=Chapter 2, Lesson 3: Changing State - Condensation= media type="custom" key="24080518"
 * It takes energy to break bonds. Energy is released when bonds are formed.**

Key Concepts

 * 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
 * Making water vapor colder increases the rate of condensation
 * Increasing the concentration of water vapor in the air increases the rate of condensation

Objective
Students will be able to describe on the molecular level how cooling water vapor causes condensation. Students will also describe the roles evaporation and condensation play in the water cycle.

Materials Needed

 * 1 short wide-rimmed clear plastic cup
 * 1 tall smaller-rimmed clear plastic cup
 * Hot water (about 50°C)
 * magnifier
 * ice cubes
 * gallon-size zip-closing plastic bag
 * 2 brown paper towels
 * white paper towel


 * 1) Watch the following video: Condensation Cup Observe the cups that are already prepared. Why doe water appear on the outside of only one of them? record your observations on your activity sheet.
 * 2) What are some examples of condensation? A real cloud is made up of tiny droplets of water. Where do you think they come from?
 * 3) What happens when water vapor condenses? Complete the procedure on your activity sheet and record your observations.
 * 4) Review the following animation: Condensation
 * 5) Does making water vapor colder increase the rate of condensation? Complete the procedure on your activity sheet and record your observations. While waiting for your results, predict whether increased cooling will increase the rate of condensation.
 * 6) On common place you see the results of evaporation and condensation is in the weather. Watch the following animation: Evaporation and Condensation Complete the Take It Further section on your activity sheet
 * 7) Evaporation and condensation can be used to purify water. Complete the Take It Further II section on your activity sheet
 * 8) Write the definition of //distillation// in your science notebook
 * 9) Place 50 milliliters of water into the graduated cylinder and place in the freezer for the next lesson

=Chapter 2, Lesson 4: Changing State - Freezing= media type="custom" key="24080586"

Key Concepts

 * 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

Objective
Students will be able to explain on the molecular level why a low enough temperature can cause the water vapor in air to condense to liquid water and then freeze to form ice.

Materials Needed

 * Empty metal can
 * salt
 * ice
 * metal spoon
 * teaspoon
 * paper towel
 * pliers
 * duct tape


 * 1) Watch this video and record your observations on your activity sheet: Ice Bomb
 * 2) Watch the following video: Ice Can Complete the experiment on your activity sheet and record your observations.
 * 3) Review the following animations: media type="file" key="ice_structure.wmv" width="300" height="300" Ice Structure & media type="file" key="ice_at_different_angles.wmv" width="300" height="300"Ice at Different Angles Complete the chart on your activity sheet
 * 4) Watch the following video and record your observations on your activity sheet: Liquid Nitrogen
 * 5) Review the following photos and videos and complete the Take It Further section: Frost, Snow Crystals, Snow Crystal Video
 * 6) Draw your own snowflake or ice crystal

=Chapter 2, Lesson 5: Changing State - Melting= media type="custom" key="24080642"

Key Concepts

 * 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

Objective
Students will be able to explain on the molecular level the process of heat transfer and molecular that causes a solid to melt to form a liquid. Students will also be bale to explain how the arrangement of water molecules is different from most other substances when it changes state from a solid to a liquid

Materials Needed

 * 2 pieces of ice
 * 2 small clear plastic cups
 * water
 * brown paper towel
 * cold water
 * hot water

3. Watch the following animation: Melting Ice Review the following image: Ice and Water How did the motion of the water molecules change as the ice melted? Write your observations down on your activity sheet. 4. This diagram illustrates the motion and arrangement of atoms or molecules in a single substance (not water) when it changes between a solid, liquid, and gas. Label your diagram with the name of the state change that takes place on each curved arrow. 5. Water does something very unusual when it freezes to become ice. The molecules, which were moving closer and closer together, move further apart as they organize themselves into the open ring pattern shown above for ice. This is why ice expands when it freezes. Answer the questions on your activity sheet 6. Use your water molecule model to represent a six-sided ring of ice. Take photos of each stage. Now use them to represent what happens when ice melts; water evaporates; & water vapor condenses. Use the models carefully as you will be using them in future lessons. 7. Watch these videos & complete the Take It Further section on your activity sheet: Dry Ice, Dry Ice in Water, Dry Ice in Hot and Cold Water 8. Review the information on the heating/cooling curve on this page: Heating/Cooling Curve 9. Complete Chapter 2 Student Reading (in Dropbox folder under Science)
 * 1) Watch the following video: Ice Melting on Different Surfaces Write your observations on your activity sheet
 * 2) How can you make the ice melt faster? How could you set up an experiment to test your method? Try this experiment:
 * Add room-temperature water to a cup until it is about 1/2-full
 * Place a small piece of ice in the water and another small piece of ice in a cup without water
 * Record your observations on your activity sheet