"I hope I have helped to raise the profile of science and to show that physics is not a mystery but can be understood by ordinary people." -Stephen Hawking
Physics is known as the knowledge of nature and is the natural science that studies matter, motion and its behaviour through space and time. While studying physics, pupils learn more about energy and force.
Some may think that physics is too difficult of a subject to grasp due to its equations and inspecting of scientific topics. Nevertheless, this is not the case due to the fact that it is a scientific discipline that can be studied by all interested ones no matter what their previous expertise was.
In the United Kingdom, physics and its various sub-topics such as energy can be studied as a GCSE subject when students are in their last years of secondary school.
Superprof will now examine the GCSE Physics Syllabus' first topic of Energy in order to help potential students decide if this syllabus is for them. Since there are various examination boards across the United Kingdom offering GCSE qualifications, we will closely review the GCSE Physics Syllabus that is offered by the Assessment and Qualifications Alliance (AQA) in a series of articles.
Changes in Energy Stores
The GCSE Physics option is part of Single Science and is divided into eight different topics. The first of the eight topics is Energy. Like all of the topics in this section, it is divided into different sections of learning. The first of the five main sections in the Energy topic of the GCSE Physics option provided by the AQA is Changes in Energy Stores.
Energy can be described as being separated into different "stores." It cannot be destroyed or created but transferred or stored in distinct ways.
The seven main stores of energy are furthered examined in this section and be described as the following:
- Magnetic: the energy is stored when repelling poles have been pushed closer together or when attracting poles have been pulled farther apart from each other. Examples of this energy store can be seen in fridge magnets and compasses.
- Internal or thermal: in objects that are higher in temperature, particles have more internal energy and can vibrate faster than other objects. Some examples of this energy store can be observed in human bodies, hot coffees or stovetops.
- Chemical: the energy that is stored in chemical bonds and can be observed in foods or muscles.
- Kinetic: the energy of a moving object. Some examples of this energy storing can be observed in those who run, buses and practically anything that moves.
- Electrostatic: the energy stored when repelling charges have been moved closer together or attracting charges have been pulled farther together. This can be seen most commonly in thunderclouds.
- Elastic potential: energy stored when an object is stretched or squashed.
- Gravitational potential: the energy of an object that is in the air at a significant height. Examples include airplanes or kites.
Energy can remain in the same store for hundreds or even millions of years or sometimes only for a slight period of time such as a second or fraction of a second. These are known as energy transfers and they can be observed all the time.
Energy can be transferred in one of four energy transfers known as:
- Mechanical work,
- Electrical work,
The word "work" is used as a scientific way of saying that energy has been transferred.
Energy flow diagrams have been created to show how energy has been transferred from one store to another. The most commonly utilized diagrams are the transfer diagrams and the Sankey diagrams.
In this first section in the Energy topic of the GCSE Physics syllabus, students are also taught about energy dissipation which is a scientific term used to describe ways in which energy is wasted and not fully utilized. Energy is usually lost by heating up the surroundings or is dissipated as sound waves.
Energy can also be conserved and there are various examples that students analyze to understand this concept of physics.
Students also learn the calculations of kinetic energy using an important equation. Exercises are undergone to test understanding of this physical equation.
Work, Power and Efficiency
Energy is an extremely crucial part of physics due to the fact that it allows work to be done. The rate at which energy is transferred is called power and the amount of energy that is transferred is known as efficiency. While students are studying the first topic of Energy they analyze the definitions, examples, and equations in work, power and efficiency.
When a force causes a body to move, work is being done on the object by force. When the work has been completed, the energy has been transferred from one store to the other. It can be described this way: energy transferred= work done.
The work that was done and the energy transferred can both be measured in joules (J).
Calculating work done depends on two things: the size of the force acting on the object and the distance through which the force causes the body to move. The equation is the following, work done= force x distance or W= F x d.
The work done is measured in joules (J), force is measured in newtons (N) and distance (d) is in the same direction of the force and is measured in metres (m).
Students next analyze the equation of power. The more powerful a device the more energy it will transfer per second. Calculating power can be done using a simple formula that is not too difficult to grasp:0r
(Images are courtesy of BBC.com/bitesize/guides)
Power is measured in watts (W), work done (W) is measured in Joules (J), and time (t) is measured in seconds (s).
One watt is equal to one joule per second (J/s). This brings students to the conclusion that for every extra joule that is transferred per second, the power is increased by one watt.
Devices such as televisions, refrigerators and washing machines are designed to waste as little energy as possible. As much energy input as possible should be transferred into useful energy stores. Efficiency is defined by determining how good a device is at transferring energy input to useful energy output.
An efficient device wastes very little energy and an inefficient device wastes a lot of energy.
Students in this section learn equations to determine efficiency as a decimal or percentage. The equations are as follows:
(The images above are courtesy of BBC.com/bitesizes/guides.)
Examples and questions of efficiency and power are analyzed in the GCSE subject of Physics.
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Energy and Heating
In this third section of the topic of Energy, students examine different concepts and perform various experiments. First and foremost pupils learn the basics of how energy is transmitted by conduction, convection or radiation. The conductivity of different materials can be determined by comparing the time taken to transmit energy through them.
Conductors are materials that allow internal or thermal energy to be transferred through it relatively easy. All metals are very good conductors.
Insulators are materials that will not allow the easy flow of energy through it. A cushion on a dining room chair would be an insulator since energy or heat will not transfer through it rapidly.
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This a measure to determine how well a material conducts energy when heated. There are many experiments that can be done to discover this using a Bunsen burner. Rods made of different materials can be heated and the one that heats the quickest is said to have a high thermal conductivity.
The thermal conductivity is watts per metre per degree Celsius (W/m/°C). For example, copper has a thermal conductivity of 385, glass has one of 0.17 and brick has one of 0.15.
Required Practical: Investigating Methods of Insulation Parts 1 & 2
Students need to complete some required practical investigations during this section of Energy.
Pupils investigate different methods of insulation and remember the importance of recording and making correct measurements of time and temperature, observe the effect of different materials as thermal insulators and use appropriate scientifical objects to measure the effectiveness of different materials.
Heating materials, the heating capacities of different objects and calculating thermal energy changes are all analyzed in this section to further understand the topic of Energy.
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All humans, animals and man-made devices transfer energy. The energy transferred is mostly supplied by electricity which was generated from other energy sources. There are both renewable and non-renewable sources of energy.
Almost everything needs energy and there are various resources of energy available on planet earth. Some of these energy resources include fossil fuels, nuclear fuel, bio-fuel, wind, hydroelectricity and geothermal just to name a few.
Energy is needed in a variety of places for many different things such as the following:
- Homes: used mostly for cooking food on the stove and heating the house during wintertime.
- Public places: in hospitals, schools, and government-owned buildings to run machinery and cool or warm the rooms.
- Industries and factories: for running heavy-duty machines and production chains.
- Public and private transport systems: cars, buses, and trucks need a fuel source and many trams or trains are connected to an electric power source.
Students analyze where most energy resources are needed, how some can cause damage to the environment and the patterns and trends of energy consumption.
The definition and examples of renewable and non-renewable energy resources are taught to pupils in this section; you may want a maths and physics tutor to go over them with you.
It is important to note that non-renewable energy resources damage the earth more than renewable resources. The following table describes the features of some of the most common renewable energy resources used today:
|Energy Resource||Energy Store||Various Uses||Environmental Impact|
|Geothermal||Thermal||Generation of Electricity and Heating||Very little|
|Hydroelectricity||Gravitational Potential||Generation of Electricity||Local inhabitants and wildlife are affected by large areas that are flooded|
|Sun||Nuclear||Generation of Electricity and Heating||The solar panels are of very little damage to the environment|
|Wind-Power||Kinetic||Generation of Electricity||According to many windmills ruin views and require too much space|
Sample Exam Questions and Assessments
After the first four topics of the GCSE Syllabus are completed, students undergo Paper 1 or the first assessment. It is comprised of a written exam of an hour and 45 minutes, Foundation and Higher Tier, it is graded out of 100 marks and is worth 50% of the GCSE.
The questions are multiple choice, structured, closed short answer and open response.
Here is a slight description of the potential questions found on the examination:
- Multiple choice questions: these are the easiest to complete because all you do is tick the correct answer. They may not require very much time to complete but they can be extremely tricky due to the fact that there are sometimes two options that seem like the correct answer.
- One and two mark questions: can be identified by command words such as "describe" or "explain." If the question is worth one mark it is essential to provide one explaining answer and if it is worth two marks you need to give two different answers.
- Three and four mark questions: they usually require longer answers than the others. However, they have similar words to the one and two mark questions.
- Maths questions: these ones usually start with the words, "calculate" or "determine" and the work that helped you arrive at your conclusion needs to be shown to earn full marks. Rulers and calculators are accepted in the exam to give a proper answer to the questions that may have a graph or table.
- Practical questions: these questions are set on required practicals that have been previously completed. Some of these questions may also c0ver scientific terms.
- Six mark questions: these are often considered the most difficult for students. It is important to plan your answer carefully to avoid becoming distracted from the point. It is crucial to give a logical answer that links all main points and sometimes you will be asked to compare two things.
- Equations: these questions require you to recall equations that have been taught during class time.
All the information that we have considered in today's article gives students a heads up of what to expect when studying the first topic of Energy in the GCSE Physics Syllabus offered by the AQA. Preparation is essential to succeed and rise above your classroom competitors.
It would be wise to observe the other topics considered in the GCSE Physics Syllabus such as electricity, particle model of matter, atomic structure, forces, waves, magnetism and electromagnetism and space physics before deciding to study this GCSE subject.
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