6.3.1 Changes of state and the particle model (Green Topic) Flashcards
What is the current from a cell?
Direct current (DC)
What happens in a direct current?
The electrons only ever travel in one direction.
What is the current from mains electricity in the Uk?
Alternating current (AC)
Key feature or alternating current?
The current is constantly changing direction
What is the benefit of using alternating current?
That it is very easy to use a transformer to increase or decrease the potential difference.
What is the frequency of alternating current in the Uk?
50 hertz (Hz)
What is the potential difference or alternating current in the Uk?
Around 230 volts
Properties of solids?
- Particles are very close together
- Particles arranged in regular pattern
- Particles vibrate but do not move from place to place
Properties of liquids?
- Particles close together
- Particles not arranged in regular pattern
- Particles can move around each other
Properties of gases?
- Particles are very far apart
- Particles not arranged in any pattern
- Particles are moving very rapidly
Define density?
The density of a material tells us the mass for a given volume.
Why does a brick have a high density?
Because it has lots of mass packed into it’s volume
Why does a polysyrene block have a low density?
Because it has a lower mass packed into it’s volume
Why do solids usually have a high density?
Because the particles are packed closely together, solids have a lot of mass for their volume.
Why do liquids usually have a high density?
Because the particles are close together liquids have a lot of mass for their volume.
