Where does Earth's energy come from?
Most of the energy that drives the Earth system comes from the sun. The sun emits energy in the form of electromagnetic radiation. This radiation travels through empty space, sometimes being intercepted by Earth's atmosphere. Visible light is one form of electromagnetic radiation that is capable of reaching Earth's surface. When it interacts with materials, the energy that is absorbed can result in a temperature change.
How does energy move from one place to another?
Energy on Earth can be transferred from one place to another by one of three methods: radiation, conduction, or convection. An example of radiation is the energy that travels from the sun through space to Earth's surface. Conduction occurs when thermal energy is transferred between two objects that have physical contact with each other. Convection is when warm air moves in where cold air is and warms up the cold air.
All three types of energy transfer must be taken into consideration when planning an energy efficient home. Radiation from the sun is used as a heat source, while heat transfer via conduction or convection can ensure that energy is efficiently moved all throughout the house.
How does the sun's radiation interact with materials?
Materials called insulators can block the energy transfer. Insulators are used in homes as a way to prevent heat from entering the house during the summer or leaving the house during the winter. A home insulating material is rated by its thermal resistance, or R-value. A material with a high R-value will prevent more heat transfer than a material with a low R-value.
Some materials have the ability to absorb energy and release it at a later time. This is useful in that the material can be heated during the day, but at night when the air temperature drops, the energy stored in the material will transfer to the air warming it up. These materials are said to have a high thermal mass (TM, for short).
What is a "green" home?
A "green" home refers to a home that was built to using techniques or materials that reduces its impact on the environment. Typically, these homes are environmentally friendly because they conserve energy and water. Green homes often make use of recycled building materials even further reducing its environmental impact.
What is thermal mass?
Imagine a pot of water and a single drop. Both can get hot, but which takes longer to heat up? The pot, right? That's because of thermal mass.
Think of thermal mass like how much thermal energy (heat) a material can store. The more stuff (mass) in an object, the more "heat" particles it can hold, like a bigger bucket holding more water. So, a massive pot of water has a higher thermal mass than a tiny drop. This means it takes more thermal energy to raise the temperature of the pot compared to the drop.
Thermal mass is important in our daily lives. A brick house with high thermal mass stays cool in summer (takes a lot of heat to warm up) and warm in winter (holds onto heat). This is why a glass of cold lemonade heats up faster than a swimming pool on a hot day!
What is a material's R-value?
R-value stands for resistance to heat flow. The higher the R-value, the more it fights against thermal energy moving from one place to another. So, a high R-value insulation in your walls is like a super thick coat for your house. It keeps the warm air inside during winter and the hot air outside during summer.
Think of it this way: Low R-value is like a strainer, letting thermal energy flow through easily. High R-value is like a thick wall, keeping the thermal energy where you want it! This saves energy on heating and cooling your house, keeping you comfy and helping the environment.
What is an earth-sheltered home?
Imagine a cozy hobbit hole! An earth-sheltered house is kind of like that. Instead of building walls that reach all the way to the roof, part of the house is built into a hill or slope. So, one or more walls are made of earth!
This earth acts like a giant blanket for the house. In summer, the cool ground keeps the inside nice and chilly. In winter, the earth helps trap heat inside, like a natural insulator. It's like having built-in air conditioning and heating!
Earth-sheltered houses can also be super energy-efficient because they use less material for walls and need less heating and cooling. Plus, they can look pretty cool tucked into the landscape!
How does the season affect the amount of sunlight?
Earth's tilt is the secret culprit behind the changing daylight hours throughout the year! Imagine Earth as a giant, tilted beach ball orbiting the sun. In summer (for your hemisphere), the North Pole (or South Pole for the other hemisphere) leans directly towards the sun. This means sunlight hits your part of the Earth more directly, like a beach ball catching the sun head-on. Sunshine reaches your window for a longer stretch, making summer days feel long and bright.
But wait, there's a twist! In winter, the opposite pole is tilted towards the sun. Now, sunlight hits your window at a slant, like trying to shine a flashlight through a crack in a door. Less sunlight gets through, making winter days shorter and dimmer. The tilt acts like a giant light dimmer switch in the sky, controlling how much daylight reaches your window depending on the season!
What are some ways that a person can reduce his impact on the environment?
One important way that you can reduce your impact on the environment is to conserve energy. By using less energy to heat and cool a home or power electrical appliances, you are indirectly reducing the amount of fossil fuels that have to be used. In most power plants, coal is used to generate electricity. Because coal is a limited resource, we risk the danger of it eventually running out. Also, the burning of coal adds pollutants to the atmosphere, which can add sulfur dioxide and carbon dioxide leading to acid rain and global warming. You can also conserve water. Fresh drinking water makes up less than 1% of the available water on Earth, so it is important to conserve it. Additionally, you can reduce your impact on the environment by recycling, and using alternative energy resources.
Here are some definitions to help you in your Grade 3-5 Lesson 1 investigation.
Temperature - how hot or cold something is. As the temperature of a material increases, the motion of the particles in the material also increases.
Heat - an amount of energy passed from one material to another because of a temperature difference between the two materials
Energy - the ability to do work
Conduction - the movement of heat energy from one material to another by direct contact between the materials
Conductor - a material that allows heat energy to easily pass through the material
Insulator - a material that keeps heat energy from easily passing through the material
Shelter - to protect something from harm
Here are some definitions to help you in your Grade 3-5 Lesson 2 investigation.
Heat - an amount of energy passed from one material to another because of a temperature difference between the two materials
Conduction - the movement of heat energy from one material to another by direct contact between the materials
Convection - the movement of heat energy from one place to another by the movement of a fluid (a liquid or gas)
Radiation - the movement of energy through empty space by electromagnetic waves
Conductor - a material that allows heat energy to easily pass through the material
Insulator - a material that keeps heat energy from easily passing through the material
Imagine that you're an architect and an environmentally conscious client just asked you to design a home that would use less energy from fossil fuels for heating during the winter season. In order to present the best design, you must first research all of the factors that go into making this house more energy efficient. You can select combinations of features to determine the impact they have on the amount of energy used in the home. Can you create the an energy-efficient home design to impress your client?
