Today’s special

• Turn in Practice test & Lab on front table

• Test 9 Thermal energy

• Turn in test and work on Vocab sheet quietly, without talking

• Vocab 10 due next

• Notes!

Heat transfer and phase change

PAc.1: Distinguish chemical properties of matter (including reactivity) from physical properties of matter (including boiling point, freezing/melting point, density

[with density calculations], solubility, viscosity, and conductivity).

PAc.6: Compare the properties of the four states of matter—solid, liquid, gas, and plasma—in terms of the arrangement and movement of particles.

PAc.7: Explain the processes of phase change in terms of temperature, heat transfer, and particle arrangement.

PAa.2: Use appropriate laboratory apparatuses, technology, and techniques safely and accurately when conducting a scientific investigation.

PAa.9: Use appropriate safety procedures when conducting investigations.

Write it on your heart that every day is the best day

of the year.

Ralph Waldo Emerson

Fact: Every year, the moon moves ½ inch further from the earth.

Today’s special

• Homework check (Vocab 10)

• Test results

• Notes

• HW I due next

• Activity (Practice book)

Question

• Why does water in a car radiator sometimes boil explosively when the radiator cap is removed?

Conduction

• Transfer of heat by means of particles, mainly electrons

• Metals have freely moving electrons, and are generally good conductors

Insulators

• Substances with electrons that do not move freely

• Wood, air, rubber

Home insulation

• Has “R” rating according to climate

Today’s special

• Safety moment

• Notes

• Class work time

The best insulator

• Dead air space, i.e.:

• Double pane windows

• Polystyrene

Convection

• Heat transfer by motion of currents in fluids, liquid or gas

What is forced convection?

• The currents are helped along by adding a fan

Radiation

• (radiant energy, NOT radioactivity!)

• Transfer of heat energy by electromagnetic waves

radiant energy

• All substances above absolute zero absorb, emit, and reflect radiant energy

Phase change

• A change of state from solid, liquid, or gas

Today’s special

• HW check

• A few more notes

• Lab

Today’s special

• HW I check

• Upcoming schedule

• Chapter project & HW II

• Safety project & Take-home test

• Lab

• A few more notes

Evaporation

• Molecules absorb energy until they can break free of the liquid

condensation

• Molecules give up their energy to a liquid

Boiling and pressure

• Boiling points can be changed by increasing or decreasing pressure

• Increased pressure prevents molecules from leaving (pushing down on the “pile”)

• Decreased pressure helps molecules to leave (helping the football players up)

Pressure cooker

Melting and freezing

• Add energy, molecules move more and substance melts

• Take out energy, molecules slow down and arrange themselves into a solid

• Adding a “foreign” substance interferes with the crystal formation process

Melting ice

Question

• Why does water in a car radiator sometimes boil explosively when the radiator cap is removed?

Homework

• Chapter HW: pp. 166-168

• I. Review questions2-20 even (due date: ____________)

• II. Exercises 2-20 even; Problems 1-7 (due date: __________)