Science term 1

Planets in the Solar System

There are 8 planets.

Dwarf Planet

Pluto was downgraded to a dwarf planet.

Center of the Solar System

The Sun is at the center of the Solar System.

Full Moon

The phase of the Moon when the entire Moon is visible.

Seasons on Earth

Caused by the tilt of Earth’s axis as it orbits the Sun.

Main Phases of the Moon

There are 8 phases: new, waxing crescent, first quarter, waxing gibbous, full, waning gibbous, last quarter, waning crescent.

Orbit

The path planets take around the Sun.

Gravity

The force that keeps the Moon close to Earth.

Seasons in Hemispheres

The Northern and Southern Hemispheres experience opposite seasons.

Earth's Orbit Duration

It takes 365.25 days for Earth to orbit the Sun once.

Moon's Orbital Duration

It takes about 28 days for the Moon to orbit Earth once.

Gravity Definition

The force by which a planet or body draws objects toward its center; stronger with greater mass.

Planet with Most Gravity

Jupiter has the most gravity relative to Earth.

Planet with Least Gravity

Mercury and Mars have the least gravity relative to Earth.

Stars Composition

Stars are primarily made of hydrogen and helium.

Types of Stars

Four types include main sequence, red giants, white dwarfs, supergiants.

Smallest Planet

Mercury is the smallest planet.

Hottest Planet Misconception

Mercury isn't the hottest because it has almost no atmosphere to trap heat.

Brightest Natural Object

Venus is the brightest natural object after the Sun and Moon.

Only Planet with Liquid Water

Earth is the only planet known to have liquid water and life.

Red Planet

Mars is known as the Red Planet.

Great Red Spot

Jupiter has the Great Red Spot, a storm raging for over 300 years.

Planet with Rings

Saturn is known for its famous and visible rings.

Extreme Axial Tilt

Uranus has an extreme axial tilt of about 98 degrees.

Furthest Planet from the Sun

Neptune is the furthest planet from the Sun.

Scientific Model Definition

A representation of a person, thing, or proposed process, typically smaller than the original.

Solar System Models

The two main historical categories are Geocentric and Heliocentric.

First Geocentric Model Creator

Plato produced the first geocentric model in the 4th century BC.

Retrograde Motion Problem

Retrograde motion caused planets to appear to move backwards.

First Heliocentric Model Creator

Aristarchus proposed the first heliocentric model around 250 BC.

revived Heliocentric Model

Copernicus revived the heliocentric model in the 1500s with better math.

Telescope Evidence for Heliocentric Model

Galileo provided key evidence such as Jupiter’s moons.

Galileo's Moon Observations

He observed mountains, valleys, and craters on the Moon.

Jupiter's Moons Discovery

Galileo discovered moons orbiting Jupiter.

Venus Phases Discovery

Galileo observed phases of Venus, proving it orbits the Sun.

Milky Way Composition Observation

Galileo observed the Milky Way is made of millions of tiny stars.

Seasons Misconception

The misconception is that seasons are due to Earth's distance from the Sun; it's actually due to tilt.

Summer in Brisbane

Summer occurs when the Southern Hemisphere is tilted towards the Sun.

Equinox Definition

Days and nights are approximately of equal length.

Solstice Definition

The longest or shortest day of the year.

Seasons in Mid-latitudes

Mid-latitude places usually have 4 distinct seasons.

Tropical Seasons

Tropical places usually have 2 seasons, wet and dry.

Arctic Seasons

Arctic places effectively experience 2 continuous seasons of daylight or darkness.

Full Lunar Cycle Duration

About 28 days.

Waxing vs Waning Moon

Waxing means growing lit portion; Waning means shrinking lit portion.

What Causes Tides

Tides are caused by the gravitational pull of the Moon and the Sun.

Spring Tides Occurrence

Spring tides occur when the Sun, Earth, and Moon are aligned.

Neap Tides Occurrence

Neap tides occur when the Sun, Earth, and Moon are at right angles.

Tide Frequency

Usually, there are 2 high and 2 low tides per day.

Solar Eclipse Alignment

Occurs when the Moon is between the Sun and Earth.

Lunar Eclipse Alignment

Occurs when the Earth is between the Sun and the Moon.

Umbra Definition

The dark central part of a shadow in a total eclipse.

Penumbra Definition

The lighter outer part of a shadow in a partial eclipse.

Total Solar Eclipse Rarity

Total solar eclipses are rare because the Moon’s shadow is small.

Looking at Solar Eclipse Caution

You should never look directly at a solar eclipse to avoid permanent eye damage.

First Nations Sky Observing Duration

First Nations Australians have been observing the sky for at least 65,000 years.

Uses of Sun, Moon, Stars by First Nations

Used for timekeeping, navigation, seasonal calendars, and cultural practices.

Wang Zhenyi

An 18th-century Chinese astronomer who modelled eclipses and challenged superstitions.