Week 4
Do the Earth or Moon create shadows?
Embedded Files
learning intentions
learning intentions
I understand how eclipses happen.
I can distinguishing between the two types of eclipses and their observable characteristics.
I understand what a satellite is
success criteria
success criteria
I can draw the relative positions between the Sun, Earth, and Moon that cause solar and lunar eclipses
I can identify the umbra and penumbra shadows of the moon and explain from the perspective of Earth what the moon looks like then.
I can define a satellite based on it's movement and distinguish between natural and artificial satellites.
Tasks
Tasks
Knowledge & understanding
Tides & Gravitational Pull Worksheet on Toddle
Satellites - natural and artificial
Eclipse Worksheet on Toddle
Knowledge and understanding
What is an eclipse?
What is an eclipse?
An eclipse happens when a planet or a moon gets in the way of the Sun’s light. It is effectively a shadow. On Earth, we can experience two kinds of eclipses: solar eclipses and lunar eclipses.
Solar Eclipse
Solar Eclipse
A solar eclipse happens when the Moon gets in the way of the Sun’s light and casts its shadow on Earth. That means during the day, as the Moon moves between Earth and the Sun it gets darker.
It can only occur at a New Moon when the Moon passes between Earth and Sun. The Moon’s shadow isn’t very big, so only a small portion of places on Earth will be able to view this. If the Moon’s shadow happens to fall upon Earth’s surface at that time, we see a portion of the Sun’s disc covered or ‘eclipsed’ by the Moon. How much it covers depends on a couple of factors:
• The distance the Moon is from Earth, which varies slightly as the Moon’s orbit isn’t a perfect circle.
• The geometry of the Sun, Moon, and Earth due to the Moon’s orbit being angled to Earth’s.
Because the Moon’s orbit around Earth is tilted 5 degrees to Earth’s orbit around the Sun, the Moon’s shadow usually misses Earth as it passes above or below our planet at New Moon.
The moon’s shadow (and all others to some extent) has two parts:
Umbra - the dark, inner shadow
Penumbra - the outer lighter shadow
The umbra is the dark center portion of a shadow. The Moon's umbra causes total solar eclipses, and the Earth's umbra is involved in total and partial lunar eclipses.
lunar eclipse
lunar eclipse
Lunar eclipses happen when Earth positions itself between the sun and the moon, casting a shadow across the lunar surface.
They can only occur during a full moon and are a popular event for skywatchers worldwide as they do not require any specialist equipment to enjoy (unlike solar eclipses).
In 2023, Earth will experience two lunar eclipses. The first lunar eclipse of 2023 was a penumbral lunar eclipse on May 5 and was visible across parts of Africa, Asia and Australia. The second and final lunar eclipse of 2023 will be a partial lunar eclipse on October 28 and will be visible across parts of E. Americas, Europe, Africa, Asia and Australia To find out when, where and how to see this year's lunar eclipses, check out our lunar eclipses 2023 guide.
task 1: Eclipse hyperdoc in classrooms
task 1: Eclipse hyperdoc in classrooms
Investigation skills
Task 2: Establishing the link between moon phases and tides
Task 2: Establishing the link between moon phases and tides
Coastal Aboriginal and Torres Strait Islander people linked lunar phases to the different tides and incorporated this into their knowledge systems. This knowledge informs hunting, fishing, and agricultural practices4. For example, Torres Strait Islanders observe the lunar phases to know the best times to go fishing. Elders explain that they prefer to fish during a neap tide rather than a spring tide. The main reason is that the stronger spring tides stir up the sediment, clouding the water, thus reducing the ability for fish to see the fisher’s lures, or the fishers to spot the fish. They explain that the best time to fish is during first and third quarter Moons, as these tides are foretold in the Moon.
There are usually two high-tides and two low-tides per day and they gradually increase in amplitude as the Moon goes from a Quarter Moon to either a Full or New Moon, then decrease as the Moon goes towards its Quarter phases. Since the Moon does not orbit the Earth in a circle, but rather a slight ellipse, the Moon is sometimes closer to us. Same applies with the Earth and Sun. If this occurs when the Earth reaches its closest point to the Sun, their combined gravity causes King Tides. The Earth reaches its closest point to the Sun around 2 January each year. If we get a Full or New Moon on or around this date, we will get a King Tide. In places like the Torres Strait, these can be very damaging as climate change causes the sea level to rise6.
Murray Island - location and image
In this activity you will calculate the difference between high tide and low tide (tidal amplitude) on the day of each lunar phase throughout the year for Mer (Murray Island). You need to work in groups and one person will find when each lunar phase occurs for each month and the other person will calculate the amplitude of the tide for that day. You will then plot this data to show the correlation between the phase of the moon and the height of the high tide.
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