In this lesson, students will conduct two chemical reactions. In the first, the temperature will go down (endothermic), and in the second, the temperature will go up (exothermic). Students will see an animation to show that it takes energy to break bonds and that energy is released when new bonds are formed. Students will use this idea to explain why a reaction is either endothermic or exothermic.
Students will be able to define an endothermic and exothermic reaction. Students will be able to use the concept of energy in bond breaking and bond making to explain why one reaction can be endothermic and another reaction can be exothermic.
In this lesson, students will make two clear colorless solutions (baking soda solution and calcium chloride solution). They will help design an experiment to see if the temperature of the solutions affects how fast they react. Students will then try to explain, on the molecular level, why the temperature affects the rate of the reaction.
Students will be able to identify and control variables to design an experiment to see if temperature affects the rate of a chemical reaction. Students will be able to explain, on the molecular level, why the temperature of the reactants affects the speed of the reaction.
In this lesson, students will feel the temperature change that occurs when a cold pack and a hot pack are activated. They will see that these temperature changes are due to a solid substance dissolving in water. Students will then compare the temperature changes that occur as four different solutes dissolve in water and classify these as either endothermic or exothermic. Students will be introduced to the concept that it takes energy to break bonds and energy is released when bonds are formed during the process of dissolving.
Students will be able to identify variables in an experiment to find out how much the temperature increases or decreases as each of the four solutes dissolves in water. Students will be able to correctly classify the process of dissolving as either exothermic or endothermic for each solute. Students will be able to explain that the temperature changes in dissolving are a result of the amount of energy released compared to the amount of energy used as “bonds” are formed and broken.
In this lesson, students will design an experiment to see if temperature affects the amount of dissolving of the sugar coating of an M&M.
Students will be able to identify and control variables to design an experiment to see whether the temperature of a solvent affects the speed at which a solute dissolves. Students will be able to explain, on the molecular level, why increasing temperature increases the rate of dissolving.
In this lesson, students add food coloring to hot and cold water to see whether heating or cooling affects the speed of water molecules. Students watch molecular model animations to see the effect of heating and cooling on the molecules of a liquid. Students will also draw their own molecular model.
In this lesson, students will look closely at the parts of a thermometer. After placing a thermometer in hot and cold water, students will look at molecular model animations of the liquid in a thermometer. Students will then draw a model of the molecules of a thermometer after it has been placed in hot and then cold water.
In this lesson, students will see a demonstration with a metal ball and ring showing that heat causes atoms to spread a little further apart. They will also see that cooling solid causes the atoms to get a little closer together. The same rules they have discovered about liquids also apply to solids. Based on their observations students will describe, on the molecular level, how heating and cooling affect the motion of atoms in a solid.
This lesson focuses on molecular motion in gases. Students compare the mass of a basketball when it is deflated and after it has been inflated. The inflated ball has the greater mass so students can conclude that gas is matter because it has mass and takes up space. Then students consider how heating and cooling affect molecular motion in gases. They dip the mouth of a bottle in detergent solution and observe a bubble growing and shrinking when the bottle is warmed and cooled. Students will learn that the attractions between gas molecules are so minimal that attractions can’t be used to explain the behavior of gases like they can for liquids and solids.
Based on observations of demonstrations and their own experimentation, students will be able to describe gas as matter. Students will also be able to describe, on the molecular level, the effect of heating and cooling on the motion of molecules of a gas.
In this lesson, students will do an activity in which heat is transferred from hot water to metal washers and then from hot metal washers to water. Students will view a molecular animation to better understand the process of conduction at the molecular level. Students will also draw their own model of the process of conduction.
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.
In this lesson, students will help design an experiment to see if adding energy (heating) affects the rate of evaporation. Students will look at molecular animations to help explain why heating water increases the rate of evaporation. Students will be introduced to a more detailed model of the water molecule. Students will create 3-D Styrofoam models of water molecules.
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.
In this lesson, students investigate the condensation of water vapor on the inside of a plastic cup. Then they design an experiment to see if cooling water vapor, even more, affects the rate of condensation. Students also relate evaporation and condensation to the water cycle.
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.
In this lesson, students will mix ice and salt in a metal can to make it very cold. They will then see liquid water and ice form on the outside of the can. Students will watch an animation of water molecules arranged as ice.
Students will be able to explain on the molecular level why a low enough temperature can cause the water vapor in the air to condense to liquid water and then freeze to form ice.
In this lesson, students place hot and cold colored water into room-temperature water. They observe that the hot water floats on the room-temperature water and the cold water sinks. Students will combine the concepts of temperature, molecular motion, and density to learn that hot water is less dense than room-temperature water and that cold water is denser.
Students will be able to explain, on the molecular level, how heating and cooling affect the density of water.
In this lesson, students will see a small piece of ice melt on an aluminum surface. Students will explain the energy transfer and molecular motion which cause the change in state from a solid to a liquid. Students will see and discuss animation of ice melting and compare the state changes of water to the state changes of other substances. They will also investigate the sublimation of dry ice through a teacher demonstration, or video if dry ice is not readily available.
Students will be able to explain on the molecular level the process of heat transfer and molecular motion that causes a solid to melt to form a liquid. Students will also be able to explain how the arrangement of water molecules is different from most other substances when it changes state from a solid to a liquid.
This lesson is the third of a three-part series on energy transformation. All three lessons have the general purpose of increasing students' understanding of energy transfer, its role in chemical change, and the factors that can influence this change. This lesson reinforces students' understanding of thermochemistry and electrochemistry by exposure to a process that they observe in everyday life. Through a practical experiment, this lesson allows students to understand how energy transfers during the chemical changes that occur in the rust and corrosion process and the factors that can influence these changes.
The purpose of this lesson is to help students understand that particle movement changes as a substance changes from one phase to another phase. This lesson helps students begin to move from the fundamental concept of solid, liquid, and gas to the reasoning for why the states exist under given conditions.
In this lesson, students will determine the effect of temperature on the motion of particles. The primary purpose of these activities is to introduce the students to the concept that temperature causes molecules and atoms to move faster and farther apart, which in turn causes the change from solid to liquid and liquid to gas. Students need to come to this activity with the knowledge that some solids turn into liquids when heated. They also need to understand the observable differences between a solid and a liquid.