8th Grade Science Guide

8.1: Chemistry 3 Dimensions & Progressions

Unit 2

developing a model to illustrate the relationships in particle motion relationships between temperature, density, and state of matter.

look at molecular animations to help explain why the 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.

squares of brown paper towel, 2 droppers

● Materials for Each

Student: 2 styrofoam balls (1 ½ inch), 4 styrofoam balls (1 inch), 2 fat toothpicks, school glue, permanent marker

Activity: Changing State - Condensation Lab

Objective

Overview

Materials

● I can relate the amount of energy added or taken away from a substance to the motion of molecules in the substance by developing a model to illustrate the relationships in particle motion relationships between temperature, density, and state of matter.

● 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

● Lesson Plan Materials for Each Group

● 1 short wide-rimmed clear plastic cup ● 1 tall smaller-rimmed clear plastic cup ● Hot water (about 50 °C) ● Magnifer Materials for the Demonstration ● 2 clear plastic cups ● Room-temperature water ● Ice cubes ● Gallon-size zip-closing plastic bag

also relate evaporation and condensation to the water cycle.

Activity: Changing State - Freezing

Objective

Overview

Materials

● I can relate the amount of energy added or taken away from a substance to the motion of molecules in the substance by developing a model to illustrate the relationships in particle motion relationships between

● Students will mix ice and salt in a metal can to make it very cold. They will then see liquid water

● Lesson Plan Materials for Each Group

● Empty metal soup can ● Salt ● Ice ● Metal spoon or sturdy stick ● Teaspoon ● Paper towel

and ice form on the outside of the can. Students will watch an animation of water molecules arranged as ice.

Materials for the Teacher