1. What are mechanical waves? What do you think waves carry?
Can you see waves? Examples?

2. Mechanical Waves
Mechanical waves are disturbances in matter that carry energy from one place to another.
Usually require matter through which to travel
The matter a wave travels through is called a medium.
Medium can be a solid, liquid, or gas
Some waves can travel through space…with no medium!

3. Transverse and Longitudinal Wave Which is which?

4. What happens when… A wave meets a hard surface like a wall? Reflection
A wave enters a new medium?
Refraction
A wave moves around an obstacle?
Diffraction

5. Axis
An imaginary line which runs through both
poles of a planet.

6. Rotation of the Earth The Earth is spinning upon a central axis.
The Earth's axis is tipped over about 23.5° from the vertical.
The Earth rotates around once in 24 hours.

7. Rotation of the Earth

8. Revolution of the Earth
The earth revolves around the sun.
The orbit is elliptic.
The Earth's tilt stays constant.
The Earth completes one revolution in 365 days.

9. Phases of the Moon

10. Shoot for the moon. Even if you miss, you'll land among the stars.
ECLIPSES
A solar eclipse is when an object in space casts a shadow from the sun on another object in space.
A lunar eclipse occurs when the Earth blocks the sunlight from reaching the moon.
Question: Why do lunar eclipses occur only during full moons?
Answer: That is the only time that the earth comes between the moon and sun.
Question: Why don’t we have a lunar eclipse every full moon?
Answer: The tilt of the moon’s orbit is 5° different than the earth
Question: Why does the full moon appear to be red during certain times of the year?
Answer: The light from the sun gets bent as it passes through our atmosphere causing it to appear red.

11. The region where the magnetic forces
Magnetic Fields
The region where the magnetic forces
act is called the “magnetic field”

12. All magnetic phenomena result from forces between electric charges in motion.

13. Charges Matter is made of atoms Atoms are made of sub-atomic particles
Protons are positively charged
Electrons are negatively charged
Atoms are electrically neutral
This means positive charges equal negative charges

14. Charging the Atoms
Electrons are loosely held by atoms of some materials
These electrons can be moved
Loosing these electrons makes the atoms electrically charged
Friction, conduction, and induction are three ways atoms can be charged

15. Static Electricity
Static electricity is the build up of electric charges on an object
Electrons move off an object to another causes the ELECTRIC DISCHARGE
Lightening is a wonderful and exciting example of this phenomena

16. Current Electricity
Some materials allow the charges to move freely through them
These materials are called conductors
Some examples of conductors are copper, iron, aluminum, and zinc

17. Insulators
These materials do not allow the charges to move freely through them
These materials are called the insulators
Some examples of insulators are rubber, plastic, and wood

18. Facts about Magnets 1. There are North Poles and South Poles.
2. Like poles repel, unlike poles attract.
3. Magnetic forces attract only magnetic materials.
4. Magnetic forces act at a distance.
5. While magnetized, temporary magnets act like permanent magnets.

19. Some More Facts
9. A charged particle experiences no magnetic force when moving parallel to a magnetic field, but when it is moving perpendicular to the field it experiences a force perpendicular to both the field and the direction of motion.
10. A current-carrying wire in a perpendicular magnetic field experiences a force in a direction perpendicular to both the wire and the field.

20. Series and parallel circuits
Series Circuit
Parallel circuit

21. Air Pressure
Air pressure is the result of the column of air that is above you.
There is so much air above you that at sea level you have 14.7 lbs/in2 pushing on you.
Gravity causes most of the air to be pulled down to the surface.

22. Altitude and Density Shows density of air
As the air pressure decreases, the density of the air decreases. The air particles are not squashed together as tightly the higher one goes. This is caused by gravity!
The air at sea level and at 6km has the same 21% oxygen, but at 6km there are fewer molecules, so you take in less oxygen with each breath.
Shows density of air

23. Layers in a different diagram

24. Temperature and the Troposphere
Troposphere: temperature at surface is warmed by the earth absorbing energy from the sun.
Air cools as it rises (air molecules lose energy)
The air cools by about 6.5°C for every 1-km above the ground.
In 10 KM air will cool
6.5*10=65

25. Temperature and the Stratosphere
Ozone absorbs ultraviolet radiation from the sun, causing the temperature to increase.

26. Temperature and the Mesosphere
This layer does not absorb energy from the sun, so it starts to cool again.
Without greenhouse gases, energy pretty much passes straight through!

27. Temperature and the Thermosphere
Solar radiation first hits this layer, so the few particles that are here can gain lots of energy. They move rapidly, so they have a very high temperature.
But the air is so thin here that it takes special instruments to measure the temperature accurately.
So even though it is very hot (over 1000°C), it would feel cold because there are so few particles to transfer heat to you.

28. The Troposphere Lowest (inner) layer weather occurs here
we live in it.
“tropo” means turning or changing conditions
depth varies from 9km above the poles to 16km at the equator
shallowest (least thick) layer, but contains most of the mass (90%).

29. The Stratosphere “strato” means layer or spreading out
Contains the ozone layer which absorbs energy and causes the temperature to rise
The ozone layer protects the surface from dangerous UV rays

30. The Mesosphere Drop in temperature marks beginning of mesosphere
“Meso” means middle
Most meteors burn up here

31. The Thermosphere Very top layer
Air is very, very thin, about 1/1000th as dense as the air at sea level
“Thermo” means heat
Extends from 80km to space
No definite outer edge
Very hot (over 1000°C), but since air is so thin it would not feel warm at all.
Divided into two parts, the ionosphere and the exosphere

32. The Ionosphere
Energy from sun strips the electrons from the gas molecules creating charged particles called ions.
Radio waves can bounce off of ions, allowing radio waves to travel great distances.
The aurora borealis (Northern Lights) occur here

33. The Exosphere “Exo” means outer Extends for 1000’s of miles
Satellites orbit here
No definite edge
Molecules gradually escape out into space