Night and Day (TEK 8.7A)

Rotation: the Earth rotates on its axis ONCE in about 24 hours; 1 day. The areas on Earth that are lit by the Sun experience day time, while the opposite side is dark and experiences night time.

  • The Earth rotates counterclockwise or West to East.

Seasons (TEK 8.7A)

Earth’s Tilt: The Earth’s axis has a tilt of 23.5 degrees towards the North Star (Polaris). Because of this, sometimes the Northern Hemisphere gets more or less direct sunlight than the Southern Hemisphere leading to different seasons.

Revolution: the Earth orbits the SuncounterclockwiseONCE in 365.25 days; 1 year.

Seasons experienced in the N.H. or S.H occur because of the Earth’s tilt and revolution around the Sun. Each hemisphere will experience the opposite season at the same time.

Seasons Diagram

When the Earth tilts towards the Sun, “we” (N.H.) experience summer.

When the Earth tilts away from the Sun, “we” experience winter.

Identify positions of winter and summer first, then spring and fall will be easier to identify.

Position C is winter in the N.H. Since the Earth revolves counterclockwise, the seasons will follow in the N.H. as such:

C: Winter

D: Spring

A: Summer

B: Fall

Winter

Since the Earth is tilted away from the Sun, less sunlight isdirected on the N.H., the amount of daylight hours become less, and the days will feel shorter. The climate will be much colder. (Remember that the S.H. will be experiencing summer at the same time.)

Winter Solstice: One day of the year where the least amount of daylight will be seen. In other words, the number of hours of darkness will be the greatest on this day.

Summer

Since the Earth is tilted towards the Sun, moresunlight is directed on the N.H., the amount of daylight hours become more, and the days will feel longer. The climate will be much warmer. (Remember that the S.H. will be experiencing winter at the same time.)

Summer Solstice: One day of the year where the most amount of daylight will be seen. In other words, the number of hours of darkness will be the least on this day.

Spring

Since the tilt of the Earth does not point towards or away from the Sun, both hemisphere are exposed to the same amount of sunlight. This results in mild weather that is not too hot or cold.

Spring (Vernal) Equinox: The one day of the season where there will be 12 hours of daylight and 12 hours of darkness.

Autumn or Fall

Since the tilt of the Earth does not point towards or away from the Sun, both hemisphere are exposed to the same amount of sunlight. This results in mild weather that is not too hot or cold.

Autumnal Equinox: The one day of the season where there will be 12 hours of daylight and 12 hours of darkness.

Moon (TEK 8.7B)

The moon rotates counterclockwise on its axis ONCE in about 28 days. The moon revolves counterclockwise around the EarthONCE in about 28 days. For this reason, the same side of moon is always facing Earth.

Mnemonic Devices:

Wax on, Wane off!

Waxing: White on Right, Growing Bright.

Waning: White on Left, Losing Light.


All diagrams are slightly different so you must identify the new moon first. It will ALWAYS be NEAR the Sun. Notice this diagram illustrates how the moon appears from outer space, where half is illuminated in ALL positions around the Sun. The same diagram also illustrates the moon’s appearance from Earth in different positions. We only see the half facing us.

Moon Phases from Earth Starting with New Moon:

  1. New Moon
  2. Waxing Crescent
  3. 1st Quarter: even though it appears half lit, the name is referring to where the moon is in its revolution around the Earth.
  4. Waxing Gibbous
  5. Full Moon: remember this moon phase is the farthest from the Sun.
  6. Waning Gibbous
  7. 3rd or Last Quarter: even though it appears half lit, the name is referring to where the moon is in its revolution around the Earth.
  8. Waning Crescent

Lunar Eclipse: When the Earth’s shadow is casted upon the FULL moon and appears reddish. This can only occur during a FULL moon.

Solar Eclipse: When the Moon’s shadow is casted upon the Earth during the day and blocks out the Sun. This can only occur during a NEW moon.

Be able to predict moon phases base on the time it takes to change phases. Each phase changes in about 3.5 days.

Which moon phase will be observed on April 10th?

What phase will it be on April 17th?

What phase will it be in the next 7 days?

What phase will occur on April 15th?