Year 9 Physics Assignment Revision Flashcards

Vocabulary practice flashcards covering heat transfer, energy diagrams, solar power generation, wave mechanics, and electrical current types based on the Year 9 Physics Revision Checklist.

I can use conduction, convection, and radiation to explain heat transfer in a room

In a room, heat can move in three main ways: conduction, convection, and radiation. Conduction happens when heat moves through objects that are touching, such as heat travelling through walls, windows, or the floor. Convection occurs when warm air rises from a heater and cooler air moves in to replace it, spreading warmth around the room. Radiation is the direct heat you feel from a fireplace, heater, or sunlight coming through a window, where heat travels in waves through the air.

☐ I can suggest and explain a simple way to reduce energy use

By turning a light off when leaving the room, less electricity is used because energy is not being wasted when nobody needs the light. This helps reduce overall energy consumption and can also lower electricity bills.

☐ I can identify energy input, useful output, and wasted energy

The amount of "input" energy is equal to the total "output" energy, therefore the combined thickness of the "output" arrows must be equal to the combined thickness of the "input" arrows.

Sankey Diagram

A visual representation of energy transfers and transformations where the thickness of each arrow indicates the amount of energy of that type.

☐ I can explain how solar, wind, or hydro power generates electricity

Solar - Solar photovoltaic converts sunlight directly into electricity using a technology known as a semiconductor cell or PV cell.   

Typical solar PV cells are covered in glass protected by an aluminium frame, known as a solar panel. When sunlight hits a solar panel, it excites electrons in the cells, creating an electric current. This direct current is then converted into alternating current by an inverter for use in homes and businesses.  

☐ I can describe one positive impact of solar power

Using solar power instead of fossil fuels helps reduce greenhouse gas emissions like carbon dioxide. Burning fossil fuels releases gases that cause global warming and climate change. Solar power creates electricity without burning fuel, so it produces much less pollution.

☐ I can describe one negative impact of solar power

Solar panels require a lot of energy to make before they can start producing electricity. The process involves mining and processing materials like quartz, as well as manufacturing and transporting different components such as aluminium and copper. Producing solar panels also requires very high temperatures and precise manufacturing, which uses a large amount of energy. This means solar energy has a high upfront energy cost compared to traditional fuels, which are usually extracted, processed and used in the same location.

☐ I can explain whether the system is practical for widespread use

Solar power is a practical and widely used source of energy because it is becoming cheaper, reliable, and better for the environment. Solar panels can be installed on homes or in large solar farms, require little maintenance, and can last for 25–30 years. Once installed, they produce electricity without releasing greenhouse gases, helping reduce pollution and climate change. Solar energy is also growing quickly around the world and now provides a significant share of global electricity.

☐ I can explain why digital signals are more reliable than analog signals

Digital signals are more reliable than analog signals because they are less affected by noise and interference. Even if the signal becomes weak or slightly damaged, digital devices can still correctly read the 1s and 0s, while analog signals can become distorted and lose quality.

☐ I can explain why light travels in space, but sound cannot

Light can travel through space because it is a form of electromagnetic radiation and does not need particles or matter to move through. This means light can travel through a vacuum, such as outer space, allowing sunlight to reach Earth from the Sun.

Sound, however, is a mechanical wave and needs a medium such as air, water, or solids to travel through. Sound moves by vibrating particles, passing energy from one particle to another. In space, there

☐ I can explain the difference between AC and DC

The most fundamental difference between DC (Direct Current) and AC (Alternating Current) is that DC flows in one direction only, while AC changes direction periodically. DC maintains a constant voltage, whereas AC voltage varies over time, usually in a sine wave pattern. AC is more efficient for transmitting electricity over long distances because its voltage can be easily stepped up or down using transformers, which helps reduce energy loss in transmission lines. DC is commonly used in battery-powered electronics, vehicles, and other low-voltage applications that require a stable voltage, while AC is the standard form of electricity used in homes and businesses because of its efficient long-distance transmission properties.

☐ I can explain the role of an inverter in a solar power system

Inverters operate by rapidly switching the polarity of DC power, creating an alternating current that can be used by standard appliances and electronics. This action involves sophisticated electronics to produce either a modified sine wave or a pure sine wave, depending on the model. Modified sine wave inverters are suitable for basic applications, whereas pure sine wave inverters are necessary for more sensitive electronics.