Physics - Activity Flashcards
What does our solar system contain?
The sun, eight planets, dwarf planets, natural satellites (moons)
The solar system consists of various celestial bodies including the sun at its center.
What is the name of the galaxy that our solar system is part of?
Milky Way galaxy
Define nebula.
Cloud of gas and dust
Define protostar.
A hot dense mass formed by increasing gravity
What is a main sequence star?
A star undergoing nuclear fusion of hydrogen into helium, stable due to balanced forces from outward pressure and gravity
What initiates the formation of all stars?
Gravity pulls a cloud of dust and gas together, increasing density, pressure, and temperature until nuclear fusion occurs
Fill in the blank: Fusion reactions lead to an equilibrium between the _______ of a star and the _______ of a star due to fusion energy.
gravitational collapse, expansion
What determines the life cycle of a star?
The size (mass) of the main sequence star
List the stages in the life cycle of a star.
- Protostar
- Main sequence star
- Red giant star
- Red super giant star
- Supernova
- Neutron star
- Black hole
- Black dwarf
How are elements formed in stars up to and including iron?
Fusion reactions in stars
How are elements heavier than iron formed?
During a supernova
Explain why heavier elements are formed and how they are dispersed.
The temperature and pressure in a supernova are so large that nuclei are forced together, and the explosion disperses elements throughout the universe
What do planets orbit?
Sun
What do satellites orbit?
Planets
How do satellites and planets maintain their orbit?
Gravity
What is a similarity between artificial satellites and moons?
Both orbit a planet
What is a difference between artificial satellites and moons?
Moons are natural, satellites are man-made
What is the shape of the orbit of a planet around the Sun?
Circular/Elliptical
Describe the difference between speed and velocity for an object in a circular orbit.
Speed remains the same, but velocity changes due to constant change in direction
What happens to the orbit if the speed changes?
The radius would change
Define centripetal force.
A force acting towards the center which causes an object to keep moving in a circular path
How are radius and speed related in an orbit?
The greater the radius, the slower the speed
How can you keep an orbit stable when you change the radius?
Change the speed as well
Describe and explain red-shift.
Red-shift is the observed increase in wavelength of light towards the red end of the spectrum due to an object moving away
Explain the link between the distance of galaxies from us and red-shift.
The further away they are, the bigger the red-shift
Describe the big bang theory.
The universe started from a very small region that was hot and dense and has been expanding ever since
What evidence supports the big bang theory?
- Red-shift: indicates the universe is expanding
- Change of galaxies’ speed: provides evidence of an expanding universe as further galaxies recede faster
How is a theory developed?
Scientists use observations, look for patterns in data, and form predictions
What are some examples of things we do not understand about the universe?
- How the increase in expansion of the universe is occurring
- Dark mass
- Dark energy
