Temperature and Thermal Energy 8th Grade Chapter 21 Section 1

List 5 ways to make yourself feel warmer. Do now Together… With your lab group List 5 ways to make yourself feel warmer. List 5 ways to make yourself feel cooler. GO 

Explain how temperature is related to kinetic energy. Objectives Students will… Explain how temperature is related to kinetic energy. Describe 3 scales used for measuring temperature Define thermal energy

What do you already know about Thermal Energy? True/False Statement Objects cannot have a temperature below zero on the Celsius scale. Thermal energy always moves from colder objects to warmer objects. Thermal energy from the sun reaches earth by conduction through space. Temperature depends on the kinetic energy of the molecules of a material.

What is Temperature? Temperature is a measure of the average kinetic energy of molecules. Molecules are always moving. Energy of motion is called kinetic energy. Molecules have more kinetic energy is they are moving faster. Which has more kinetic energy: iced tea or hot tea?

Object is Heated Object is Cooled Thermal Expansion 1)Object becomes warmer 2) Molecules move faster 3) Molecules move apart 4) Object expands Object is Cooled 1) Object become cooler 2) Molecules move slower 3) Molecules move closer together 4) Object shrinks or contracts

Measuring Temperature-Different Temp Scales Characteristics of Each Scale Fahrenheit Celsius Kelvin Temperature at which water freezes Temperature at which water boils Number of degrees between water’s freezing and boiling points

Organizing temperature formulas Fahrenheit to Celsius Celsius to Fahrenheit Celsius to Kelvin Formula C= (5/9)(F-32) F= (9/5)(C)+32 K= C + 273 Break it down or simplify [(F-32) x5] / 9=C [(C x9) /5] +32= F C + 273=K

Practicing Temperature Conversion A person’s body temperature is 98.6 F. What is that temperature on the Celsius scale? Answer: 37.0 C A temperature of 57 C was recorded in 1913 in Death Valley, CA. What is this temperature on the Fahrenheit scale? Answer: 134.6 F

Thermal Energy Potential Energy 1) Molecules in a material exert attractive forces on each other Ex: Gravity exerts an attractive force on a ball. 2) Molecules in a material have potential energy Ex: A ball above the ground has potential energy. 3) As molecules move closer together or farther apart, potential energy changes Ex: As a ball moves closer to or farther from Earth’s surface, its potential energy changes.

For Next Time… Read pgs. 612-615 Define heat, conduction and radiation on index cards Have test signed by a parent due Thursday. Potential and Kinetic Energy