Embedded Files
These are the Texas Essential Knowledge and Skills (TEKS). Each line describes what students are expected to know and be able to do by the time they take the STAAR assessment. I have bolded the skill portion of each student expectation to highlight what students must demonstrate.
Earth's Axis
Earth's Axis
Earth’s axis is an imaginary line from the North Pole to the South Pole through the center of Earth.
Earth rotates, or spins, on its axis. Rotation means to spin in a circle around an axis.
Remember that Earth spins counterclockwise. Counterclockwise makes it look like the sun rises from the East and set in the West.
Apparent Motion of the Sun
Apparent Motion of the Sun
The sun appears to rise in the east and set in the west. We can model the path the Sun takes and see it forms an arc. Earth's rotation causes the apparent movement of the Sun across the sky from east to west. The Sun is not actually moving across the sky. It looks like it is moving across the sky because Earth is ROTATING.
Shadows
Shadows
The Sun's apparent motion across the sky causes natural shadows on Earth to change throughout the day. Shadows in the morning and evening are long. Shadows at midday are shortest. Shadows will change direction opposite of the Sun's position.
Practice
Practice
Léon Foucault
Léon Foucault
WARNING The creator in this video is making a joke. Scientific evidence shows that Earth is round and rotates on its axis, which causes day and night.
Léon Foucault was the first scientist to prove that Earth rotates using an experiment on Earth itself—not by observing space.
Foucaul showed that Earth rotates by using a pendulum whose swing appeared to change direction because Earth was turning beneath it.
Seasons
Seasons
A pattern of increasing and decreasing light and solar energy each year, based on our distance from the Sun.
Click on the Seasons below to learn more about each one!
The Northern Hemisphere is tilted towards the Sun. The Southern Hemisphere is tiled away from the Sun.
Logest day of the Year
June 21st (solstice)
The Northern Hemisphere is tilted away from the Sun. The Southern Hemisphere is tilted toward the Sun.
Shortest day of the Year
December 21st (solstice)
Solstice: When the Sun is at its greatest distance from the equator
Equinox: When the Sun is exactly above the Equator
Ocean Tides
Ocean Tides
The rise and fall of sea levels caused by the gravity of the Sun and Moon, and Earth's rotation
Diurnal Tides: One high-tide & one low-tide each day
Mixed Tides: Similar to Semi-Diurnal tides, but the water does not rise & fall to the same level
Semi-Diurnal Tides: Two high tides and two low tides each day
Neap Tides
Neap Tides
Neap tides happen when the sun and moon pull at right angles to each other (first and third quarter moon), which makes their forces partially cancel out. This causes smaller differences between high tide and low tide; lower high tides and higher low tides than usual.
Spring Tides
Spring Tides
Spring tides happen when the sun, moon, and Earth line up (during a new or full moon). Their gravity works together, causing the highest high tides and the lowest low tides.
Day/Night Cycle
Day/Night Cycle
12 Hours of light and dark = 24 Hours = 1 Day/Night Cycle
Periods of light and Dark as Earth Rotates on its Axis.
The Lunar Cycle
The Lunar Cycle
As the Moon orbits the Earth, we see reflection of light from a different angle each night.
Just like the Earth, the Moon is a sphere, and only 50% is illuminated.
Light from the Sun reflects off of the Moon, making it appear as if it is illuminated.
Seasonal Constellations
Seasonal Constellations
A constellation is a group of stars forming a recognizable patter.
Traditionally named after its apparent form or identifed with a mythological figure.
Winter
Spring
Summer
Fall
Seasonal constellations are groups of stars that are visible at different times of the year because Earth changes position as it orbits the Sun.
Seasonal constellations are groups of stars that are visible at different times of the year because Earth changes position as it orbits the Sun.
As we move through the seasons, we face different directions in space at night, allowing new constellations to appear while others seem to disappear until the next year.
As we move through the seasons, we face different directions in space at night, allowing new constellations to appear while others seem to disappear until the next year.
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