Print bookPrint book

Week 15 - Introduction, Heat, Heating Technology and Thermal Energy

Week 15 - Introduction, Heat, Heating Technology and Thermal Energy

Site: AB Course Sharing Hub
Course: Science 7 LearnNet
Book: Week 15 - Introduction, Heat, Heating Technology and Thermal Energy
Printed by: Guest user
Date: Sunday, 18 August 2019, 2:03 PM

 


An Overview of the Module

 


INTRODUCTION

Heat is a powerful natural resource.

When it is out of control it is dangerous and devastating.When managed correctly heat energy can be used to do work.

Exercise 1.1


ACTIVITY A: Why do we need heat?



Textbook Readings

Science in Action 7
pages 180 to 184
or

Science Focus 7
pages 188-190



Humans need heat to survive. Our bodies produce heat, but it is easily lost so we must develop a way to keep our body heat and/or warm our environment. Like most technologies, heat technologies have developed from simple to complex.

Humans also use heat to cook food, which kills micro-organisms that cause disease.

Study the following charts and answer the questions below.

Exercise 1.1: Why do we need heat?

Exercise 1.2


Lesson 1.3: Thermal Energy Affects Matter in Different Ways


 Thermal Energy Affects Matter in Different Ways

Forest and prairie fires can be a very big problem for rural Albertans. The firefighters who fight them must understand how they move and grow and how to most effectively put them out. They must understand the scientific principles of heat. For the next few lessons you will learn the science of heat and how it affects your everyday life.
ACTIVITY A:



Textbook Readings

Science in Action 7
pages 190 to 197
or

Science Focus 7

pages 202 to 203

From your earlier studies in school, you know that everything on Earth and even the whole universe in made of matter.

The scientific definition of matter is 'anything that has mass and takes up space'.

Matter exists in three states: solids, liquids and gases. Matter can change back and forth to any of these three states.

For example, you are familiar with the three states of water. It can be found as a solid (ice), a liquid, or a gas (water vapour or steam).

Have you ever wondered what makes it change state?

The amount of heat that each water molecule has will determine the state of water.

In the coming lessons you will become more familiar with the role of heat.


ACTIVITY B: Solids, Liquids, and Gases


All particles on Earth have kinetic energy. But scientists have calculated that there might be places in deep space where there is no energy in particles. This theoretical temperature is called absolute zero on the Kelvin scale and it would be equivalent to -273.15°C.

Scientists have come close, but have never achieved, absolute zero on Earth.



Textbook Readings

Science in Action 7
pages 190 to 197
or

Science Focus 7

pages 202 to 203

Solids have a definite shape and volume. Volume is the amount of space matter occupies. Did your dresser or bed change shape over night? If we to closely examine the particles in a solid we would find that there are powerful attractive forces between the particles so their movement is movement in place. They move back and forth in a fixed position.

Liquids have a definite volume but no definite shape. They take the shape of the container their in. A closer examination at the particle level would reveal that there is more kinetic energy in the particles, and larger spaces between them. This allows the particles to slip by one another, but attractive forces still keep them together. This allows liquids to flow.

Gases have no fixed volume or shape. They will fill the container they are in. The kinetic energy of the particles overcomes the attractive forces between the particles and the gas particles fly of in all directions. Their bouncing and bumping into each other and the container walls keeps them apart. Only the container they are in keeps them from flying away.

It is important to note that different kinds of matter need different amounts of energy to make them change state. For example, Oxygen is a gas at room temperature while water is a liquid and various metals solid. Look around the room you are in and think of the states of matter in the room. You can easily see the solids and the liquids but detecting gases is more difficult. The air in your room contains gases like nitrogen, oxygen, carbon dioxide and even water vapour. During the winter the air in your room touches cold windows and the water in the air will change state into liquid water and even solid water in the form of frost.

Summary

The particle model states:

1. All matter is made up of extremely small particles.
2. These tiny particles are always moving.
3. Adding heat to the particles makes them move faster.
4. The particles have spaces between them.
5. There are attractive forces between the particles.
All matter can be classified as solid, liquid or gas, and there can be a change of state by adding or taking energy away.

Changes of State Diagram

There are many terms used to scientifically describe the states that matter undergoes as it gains and loses energy.


Exercise 1.2:

States of Matter Quiz

Exercise 1.4

            
Excercise 1.4
ACTIVITY A: Making your own Water Cycle!


If you have ever wondered why the bottoms of cumulus clouds are flat? It is because that is the altitude in the rising air where the gaseous water vapour changes back to liquid water droplets.
The change of state diagram can be used to describe the physical changes that all substances can go through. But, if we were to change the title of the diagram to the water cycle, it would still be correct.

The water cycle plays a very large part in ecosystems world wide. The world's weather is, in large part, caused by the uneven heating of the Earth's surface. The change of water to a gas (water vapour) is caused by the energy of the sun. But as the water vapour is carried upward by warm rising air, or over colder areas of the planet, it looses some of its energy and returns to very small droplets of liquid water and forms the clouds in the sky. The water cycle may cover huge areas of the Earth. For example, the sun may evaporate the water from the surface of the Pacific ocean. The wind then carries that water vapour for thousands of kilometres before it condenses into liquid water in the form of cloud droplets or even snow (solid water) over the Rocky mountains. Warm summer days in the mountains can melt and even evaporate some of the water collected there, to begin a new journey. The water molecules aren't destroyed, they only change state.

In fact some of the water in you right now might have been in a T-Rex or Cleopatra or a large redwood tree. The water we drink in has been in millions of places and probably thousands of organisms.




Build your Own Terrarium

MATERIALS NEEDED

  • A very large jar with screw-on lid
  • Some small stones
  • Sand if you have it
  • A small plant or two of any type
  • Some damp (slightly moist )potting soil
  • Finally you will need a shell, a large bottle cap, or a small lid filled with water

PROCEDURES

1. Layer the jar first with about 2cm of stones
2. Cover this with sand and then add potting soil to about half to a third of the jar.
3. Add your plants; making sure that the roots are in the soil.
4. Fill the small container with water. It will act as your lake in your artificial environment.
5. Finally, screw on the jar lid. You have now made a terrarium!

Now keep the terrarium in a shady spot for a few days and observe what happens.

Exercise 1.3: Make your own Water Cycle

Section 1 Notes

You will have two opportunities to write this section quiz. This quiz consists of 10 questions. Use the results from your 1st attempt to help you prepare for your second attempt. Your best score will be taken as your assessment mark. You have 10 minutes to complete this multiple choice quiz. Remember to do this quiz under testing conditions without texts, aids, or help.

Click the icon to go to the quiz.