AQA GCSE FOUNDATION PHYSICS - Efficiency: Reducing Energy Waste

AQA GCSE Foundation Physics - Efficiency: Reducing Energy Waste

What is Efficiency?

Efficiency measures how well a device converts energy from one form to another. It's a ratio that compares the useful energy output to the total energy input.

Formula:

Efficiency = (Useful Energy Output / Total Energy Input) x 100% 

Example:

A light bulb converts electrical energy into light energy. If it uses 100 joules of electrical energy and produces 20 joules of light energy, its efficiency is:

Efficiency = (20 J / 100 J) x 100% = 20% 

This means only 20% of the energy input is converted into useful light energy, while the remaining 80% is wasted as heat.

Why Reduce Energy Waste?

• Saves Money: Reducing energy waste means using less energy, leading to lower energy bills.
• Conserves Resources: Fossil fuels used to generate electricity are non-renewable.
• Reduces Environmental Impact: Burning fossil fuels releases harmful greenhouse gases, contributing to climate change.

How to Reduce Energy Waste

1. Use Energy Efficient Appliances: Look for appliances with high energy efficiency ratings, often represented by stars or letters (A+++ being the most efficient).

2. Insulate Your Home: Insulation prevents heat loss in winter and reduces the need for heating.

3. Switch Off Lights and Appliances: Turn off lights when leaving a room and unplug devices not in use.

4. Use Public Transport, Walk, or Cycle: Cars use a lot of fuel, so consider more sustainable transportation options.

5. Reduce Water Usage: Heating water uses energy. Take shorter showers, fix leaky taps, and use water-efficient appliances.

Calculating Efficiency Improvements

Example:

An old fridge uses 300 kWh of energy per year. Replacing it with a new energy-efficient model that uses only 150 kWh per year results in a 50% reduction in energy consumption.

Energy Saved = (300 kWh - 150 kWh) = 150 kWh
Efficiency Improvement = (Energy Saved / Original Energy Consumption) x 100%
Efficiency Improvement = (150 kWh / 300 kWh) x 100% = 50%

Key Points

• Efficiency is the ratio of useful energy output to total energy input.
• Reducing energy waste saves money, conserves resources, and reduces environmental impact.
• Energy efficiency improvements can be calculated to quantify savings.