Words & Motion
This spinning motion of Earth causes day and night.
What is rotation? Earth completes one rotation in about 24 hours.
Earth’s rotation axis is tilted about this many degrees.
What is 23.5 degrees?
This word means the sunlit part of the Moon we see is growing.
What is waxing? Waning means the visible sunlit part is shrinking.
These two objects cause Earth’s ocean tides.
What are the Moon and the Sun?
During this eclipse, the Moon blocks our view of the Sun and casts a shadow on Earth.
What is a solar eclipse? It can happen at new moon.
Name the path around another object AND the movement along that path.
What are orbit (the path) and revolution (the movement)? Earth revolves around the Sun in about 365 days.
These days have about 12 hours of daylight and 12 hours of night in most places.
What are equinoxes? They occur in March and September.
More than half, but less than all, of the Moon’s visible face is lit, and the lit part is shrinking. Name the phase.
What is waning gibbous?
This object has the stronger tidal effect on Earth because it is much closer.
What is the Moon? The Sun also affects tides.
During this eclipse, Earth casts its shadow on the Moon. Name the eclipse AND the Moon phase.
What are a lunar eclipse and a full moon? The order is Sun, Earth, Moon.
This imaginary line is what an object spins around.
What is a rotation axis?
This event gives the Northern Hemisphere its longest daylight period of the year.
What is the June solstice? The December solstice gives it the shortest daylight period.
At first quarter, this fraction of the Moon’s visible face is lit.
What is one-half? A quarter moon has half of its visible face lit.
High-water height is 8 feet and low-water height is 2 feet. Find the tidal range.
What is 6 feet? Tidal range = 8 - 2 = 6 feet.
Name the darkest central shadow AND the outer partial shadow.
What are the umbra and penumbra?
For the same two objects, gravity gets weaker when this increases. At the same distance, gravity gets stronger when this increases.
What are distance and mass, respectively?
When the Northern Hemisphere tilts toward the Sun, name its season and TWO reasons it is warmer.
What is summer, with more direct sunlight and longer daylight hours? The Southern Hemisphere has winter.
Explain why we see different Moon phases as the Moon orbits Earth.
What is seeing different amounts of the Moon’s sunlit half? The Moon reflects sunlight. Earth’s shadow does not cause normal phases.
These tides have the largest tidal range. Name them AND the two Moon phases when they occur.
What are spring tides, at new and full moons? The Sun’s and Moon’s tidal effects reinforce each other. Spring tides occur all year.
Explain why we do not have solar and lunar eclipses every month.
What is the Moon’s orbit being tilted about 5 degrees? It usually passes above or below the needed alignment. An eclipse needs the correct phase and alignment near a node.
Explain how gravity and forward motion work together to keep Earth in orbit around the Sun.
What is gravity pulling inward while Earth moves forward? Together they keep Earth moving along a curved orbit.
A student says, “Summer happens because Earth is closer to the Sun.” Correct the claim and explain the real cause.
What are Earth’s tilt and revolution? They change sunlight angle and daylight hours in each hemisphere. Distance from the Sun does not cause the seasons.
Explain why nearly the same side of the Moon always faces Earth. Is the far side always dark?
What is synchronous rotation? The Moon rotates once and orbits Earth once in about 27.3 days. The far side also receives sunlight. The full phase cycle takes about 29.5 days.
These tides have the smallest tidal range. Name them, the Moon phases, and the Sun–Earth–Moon angle.
What are neap tides, at first and third quarter, with a right angle at Earth? The Sun’s and Moon’s tidal effects partly offset.
Name the solar eclipse that leaves a bright ring, explain why the ring appears, and name a safe way to view it.
What is an annular solar eclipse? The Moon appears too small to cover the Sun. Use proper eclipse glasses or a safe indirect viewer; ordinary sunglasses are not safe.