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| Question | Answer |
| Definition of Mass | How much matter is in an object. |
| Definition of Weight | The amount of force, exerted by an object due to the gravitational field strength of Earth. |
| What is the unit of measurement used for mass? | Kilograms (kg) |
| What is the unit of measurement used for weight? | Newtons (N) |
| What is the equation linking mass, weight and gravitational field strength? | weight = mass x gravitational field strength |
| What is a scalar quantity? | Only has magnitude(size) e.g. mass |
| What is a vector quantity? | Has both magnitude and direction e.g. weight |
| What is the equation linking, mass, force and acceleration? | force = mass x acceleration |
| What is a resultant force? | The overall force on an object. |
| What is energy measured in? | Joules (J) |
| What is the equation for efficiency? | efficiency = useful work done(output) divided by total energy used (input) |
| How would you portray wasted and used energy? | In a sankey diagram. |
| If all forces acting on an object are in equilibrium then the object is ....... | Stationary. |
| What is radiation? | The transfer of heat by infra red waves. Infra red waves are part of the electromagnetic spectrum and have a longer wavelength than visible light. |
| Does radiation require a solid, liquid or a gas? | No. It can travel through a vacuum. This is how heat and light from the sun reaches Earth. |
| Can radiation be reflected? If so what are the best and worst surfaces for reflecting? | Yes. A good reflector is light and shiny, a poor reflector is dark and matt. |
| What is a good reflector of heat not good at? | Good reflectors of heat are poor absorbers of heat. Bad reflectors of heat are good absorbers of heat. |
| How do hot and cold objects emit and absorb radiation? | A hot object emits more infra red radiation than it absorbs. A cold object absorbs more infra red radiation than it emits. |
| What is convection? | The transfer of heat in convection currents? |
| In what substances can convection currents occur? | Liquids and gases. |
| Why can convection currents not occur anywhere else? | In solids, the particles are not able to move. |
| What is an experiment you could do to show convection currents? | Potassium manganate in water. |
| What is conduction? | The process where heat or electricity is transferred through an object by heated particles moving and transferring their motion from one place to another. |
| How does heat conduction in metals work? | Free electrons in metals are able to move freely and when a metal is heated, these particles gain more kinetic energy which allows them to move quickly and transfer their energy. |
| How would you increase the thermal energy transferred every second? | 1. If you increase the temperature difference across the ends of the object. 2. The cross section of the object is increased. 3. The length of the object is reduced. |
| What are poor conductors called? | Insulators. |
| What are some examples of insulators? | Usually non-metals, liquids and gases like wool, cardboard, water. |
| What materials are usually good conductors? | Metals. |
| Why are some insulators poor at conducting? | They contain tiny pockets of trapped air. |
| How would you measure thermal transfer? | You measure the amount of thermal energy using a thermometer. Thermometers measure temperature in centigrade or celsius, or kelvin (K). -273 C is 0 K. |
| What is Brownian motion? | The seemingly random movement of particles like smoke that have such little mass that they are jostled around by thousands of gas particles bumping into them. |
| What is internal energy? | Atoms and molecules have kinetic energy because they are moving. They also have potential energy because their motion keeps the. separated and opposes the bonds trying to pull them together. The total kinetic and potential energies of all the atoms in a material are called its internal energy. |
| What is kinetic theory? | The theory that matter is made up of tiny particles which are constantly in motion. The particles attract each other strongly when close but the attractions weaken when they move further apart. |
| How do convection currents work? (Use the potassium manganate experiment) | There is a bunsen burner underneath a beaker of water with potassium manganate 7 in it. Just above the heat, the particles of water gain kinetic energy which increases the distance between the particles. This causes an expansion of warmer water which reduces its density. As the warmer water has a lower density than the surrounding colder water it rises. As it rises, it is replaced by colder, denser water from the right hand side of the beaker. As the warm water reaches the top of the beaker, it start to cool and become more dense. It then sinks to the bottom of the beaker only to be heated and repeat the cycle. This is called a convection current. |
| What is inside an atom? | Protons, neutrons and electrons. |
| What is the charge in protons, electrons and neutrons. | Electrons are negatively charged, protons are positively charged and neutrons have a neutral charge. |
| How do you transfer electrons? | Electrons can normally transfer through friction but can also be transferred by an electric current. |
| How do you create static charge? | If you rub an insulator with a cloth, it can become charged in two ways: electrons from the cloth to the insulators, the cloth is positive and the insulator is negatively charged. Or, the electrons move from the insulator to the cloth, the cloth is negatively charged and the insulator positively charged. |
| What is induced charge? | This occurs when a charged object is brought towards an uncharged object. |
| What are examples of induced charges? | A positive side of a water stream is attracted to a negatively charged rod |
| What are the dangers of electrostatics? | If two objects have different charges there is a chance that they will spark when brought close to one another. If there is a flammable substance nearby then an explosion could occur. |
| How would you avoid this? | You can earth an objects and allow its electrons to flow to Earth, the object will then have the same charge so no spark will occur. |
| What is resistance? | Resistance is a measure of how difficult it is for a current to flow. |
| What is resistance measured in? | It is measured in Ohms (i can't insert greek symbols) |
| What is the equation to work out resistance? | resistance = potential difference (v) over current (A) amps |
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