What causes day and night on Earth?
Earth’s rotation (24 hrs, west to east).
Why do we have seasons?
Earth’s 23.5° tilt + orbit around the Sun.
When is summer in the Southern Hemisphere?
December to February.
What keeps objects in orbit?
Gravity + forward motion.
What’s the difference between natural and artificial satellites?
Natural = moons; Artificial = man-made (e.g. GPS).
Name the Moon phases (Southern Hemisphere).
New → Waxing Crescent → First Quarter → Waxing Gibbous → Full → Waning Gibbous → Last Quarter → Waning Crescent.
What is a solar eclipse?
Moon blocks the Sun (New Moon).
What is a lunar eclipse?
Earth blocks sunlight from the Moon (Full Moon).
What causes tides?
The Moon’s gravity pulling on Earth’s oceans.
Spring vs Neap tides?
Spring = strong (Sun + Moon aligned); Neap = weak (Sun + Moon at 90°).
Name the 8 planets in order.
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.
What are comets and asteroids made of?
Comets = ice + dust; Asteroids = rock.
What powers stars?
Nuclear fusion (hydrogen → helium).
Star life cycle (small star)?
Nebula → Red Giant → White Dwarf.
Star life cycle (large star)?
Nebula → Red Supergiant → Supernova → Neutron Star/Black Hole.
Types of galaxies?
Spiral, Elliptical, Irregular.
What is a light year?
Distance light travels in one year (~9.46 trillion km).
Geocentric vs Heliocentric model?
Geocentric = Earth-centred (old); Heliocentric = Sun-centred (correct).
What makes Earth habitable?
Right distance from Sun, liquid water, stable temp, protective atmosphere.
Main gases in Earth’s atmosphere?
Nitrogen (78%), Oxygen (21%), others (e.g. COâ‚‚, argon).
