Back To Basics Science Flashcards
What is matter?
Anything that takes up space
What is mass?
The amount of matter that an object contains without any gravitational force
What is mass measured in?
Kilograms (kg)
Which states can matter be?
Solid
Liquid
Gas
What is matter made up of?
Atoms
What is the volume?
The amount of space that the matter takes up
What are the features of solids?
(4)
Solids have a fixed shape
The particles are closely packed together in a regular structure
The particles vibrate around in a fixed position
Solids aren’t easily compressed
What are the features of liquids?
(4)
Liquids take up the shape of the container that they’re in
The particles are closely packed together, but there’s no regular arrangement
The particles can vibrate and move past each other
Liquids aren’t easily compressed
What are the features of gases?
(4)
Gases can take the shape of the container that they’re in
The particles are spread out with no particular arrangement
The particles can move freely
Gases are easily compressed
What is the density?
The amount of mass per unit volume
What does the density describe?
How closely packed together the particles are in solids, liquids and gases
What is density measured in?
Kilograms per metre cubed (kg/m3)
What is weight?
The downward force on an object due to the gravitational pull of the earth
How is weight measured?
Newtons
What is force?
A pull,push or other action that changes the motion of an object
What is the equation for force?
Mass x acceleration
(F = m x a)
How is force measured?
Newtons
What is work?
The force applied to an object multiplied by the distance
What is the equation for work?
Force x distance
(W = f x d)
How is work measured?
Joules
What is energy?
The ability to do work
What are the 2 types of energy?
Potential energy
Kinetic energy
What is potential energy?
The energy that’s stored
What is kinetic energy?
The energy that’s being expended (used)
When will atoms have no net charge?
Why?
When they have the same number of protons and electrons
Because the charges cancel each other out
What is the nucleus held together by?
A strong nuclear force
What is binding energy?
The amount of energy needed to split the atom
How is binding energy created?
When the nucleus is being held together by a strong nuclear force
What keeps the electrons in orbit around the nucleus?
The force of attraction between the negatively charged electrons and positively charged protons
What do electrons orbit?
The nucleus
What are electron shells also known as?
Orbits
What holds electrons in their orbits?
Binding energy
The closer the electron is to the nucleus…
(Binding energy)
The stronger the binding energy
What equation is used to calculate the maximum number of electrons that a shell can hold?
2n2 (squared) N represents the number of shells
When can an electron be removed from its orbit?
If it’s struck with an energy that’s greater than the binding energy
What is a removed electron referred to?
An ion
What is ionisation?
The process of removing an electron from its orbit, causing the removed electron to be referred to as an ion
What happens if ionisation happens in the shell nearer the nucleus?
An electron from an outer shell will drop down to fill the vacancy in the inner shell
How is x-ray produced?
(4)
Ionisation occurs in a shell near the nucleus
An electron from an outer shell will drop down to fill the vacancy in the inner shell
Energy is released in the form of electromagnetic radiation (characteristic x-ray photons)
The orbit shells fill from the shell nearest the nucleus outwards because a vacancy in a shell makes it unstable
What are the particles of an object given when heat is given to the object?
Kinetic energy
What does increasing the kinetic energy given to particles do to the particles?
It causes them to move more
What type of temperature does an object with a higher kinetic energy have compared to an object with lower kinetic energy?
An object with higher kinetic energy has a higher temperature than an object with lower kinetic energy
What is temperature the measure of?
The average kinetic energy that the particles of an object have
What is heat?
(2)
The transfer of energy from one object of matter to another, or from one part of an object to another part
How does heat transfer happen?
Because of a temperature gradient
What is a temperature gradient?
Movement of heat from an area of high temperature to an area of lower temperature
When does heat transfer stop?
When the temperatures of the 2 objects, or the parts of the same object- are the same
What is conduction?
The transfer of heat through direct molecular collision (the molecules hitting each other)
What does conduction cause?
A transfer of kinetic energy from higher kinetic energy to lower kinetic energy
When does conduction happen?
It only happens in solids when there’s a temperature gradient
Which state does conduction happen in?
Solids
What is convection?
The transfer of heat through liquids or gases
Which states does convection happen in?
Liquids
Gases
Which particles are heated by conduction?
The particles closest to the heat source
What happens to the particles that are heated by conduction?
They expand and become less dense, causing them to rise
What happens once the particles heated by conduction expand and rise?
As they rise, further particles are drawn in from the side towards the heat source and go through the same process
What happens as the particles heated by conduction rise?
The particles bump into each other, causing heat transfer to happen by the process of conduction. This causes the particles to cool down and fall.
How are convection currents created?
When the particles that were initially heated by conduction cool down and fall are reheated. This causes them to go through the process of rising, cooling and falling again (because of heat transfer), which creates convection currents
What’s an example of heat transfer?
Heating up a pan of water on a stove
What is radiation?
The transfer of heat energy through waves
What happens when waves hit an object?
Kinetic energy is transferred to the object, causing an increase in temperature. (This is how we feel heat from the sun)
Which mechanism of heat transfer is the only one that can take place in a vacuum?
Radiation
What is the electromagnetic spectrum?
A way of ordering the different radiations
What do all waves have in common?
They all have the same velocity
What varies between all waves?
(3)
Energy
Wave length
Frequency
What is the wavelength?
The distance from one peak to another
What is the frequency?
The number (no.) of cycles per second
What is frequency measured in?
Hertz (Hz)
What is the order of the electromagnetic spectrum?
(7)
Radio waves
Microwaves
Infrared radiation
Visible light
Ultraviolet
X-rays
Gamma rays
What is non-ionising radiation?
Low energy radiation with a longer wavelength
What are 2 examples of non-ionising radiation?
Radio waves
Microwaves
Which is the only electromagnetic radiation that’s visible to the naked eye?
Visible light
Which are the 2 ionising radiations?
X-rays
Gamma rays
What does ionising radiation do?
The radiation has photons which have enough energy to remove an electron from an atom- ionisation. This can cause damage to human tissue.
What are photons?
The functional unit of electromagnetic radiation
What are the 3 components of an atom?
Protons
Electrons
Neutrons
What is the nucleus made up of?
Protons
Neutrons
What is the charge of protons?
Positive
What is the charge of neutrons?
They have no charge
What is the charge of electrons?
Negative charge
What do electrons do?
They orbit the nucleus
Since electrons move very fast, what do they have a lot of?
Kinetic energy
What are elements?
Substances that can’t be broken down into simpler substances
What is each element made up of?
A unique atom with an unchanging number of protons
What determines the exact properties of an atom?
The number of protons, electrons and neutrons it has
What is the atomic number?
The number of protons in the nucleus
Why is the atomic number important?
(2)
It determines the chemical properties
It defines the element
What letter represents the atomic number?
Z
What is the atomic mass?
The combined number of protons and neutrons in the nucleus
What letter represents the atomic mass?
A
What letter represents the neutron number?
N
What is the equation for the atomic mass (A)?
A = Z + number of neutrons
(Z = atomic number)
What are isotopes?
Different forms of the same element
What is different about the atoms of isotopes?
Their atoms have the same number of protons but a different number of neutrons. Therefore, they have a different mass number
What’s an example of an isotope?
Carbon
