Thermal Energy

Thermal Energy

Today you will need:

Planners (objective)

Chromebook

Science Notebooks (taking notes)

Pencil

Notetaking Utensils (highlighters, colored pencils etc.)

Objective: I will be able to explain what temperature measures and identify three different types of heat transfer

Objective

I will be able to explain what temperature measures and identify three different types of heat transfer

Open Ended

Essential Question: Everytime you come to school, your temperature is taken before you are allowed to enter the building. How do you think thermometers work? What do thermometers measure exactly?

Open Ended

What is a conductor?

Open Ended

What is an insulator?

Open Ended

What does thermal mean?

Open Ended

What does kinetic mean?

Open Ended

What is the smallest unit of matter?

Introduction

Atoms in substances are always vibrating and moving. If you were to look at your pencil you wouldn't be able to notice anything because atoms are too small to see.

Solid

This is close up view of particle interactions with each other in a SOLID substance

Liquid

This is close up view of particle interactions with each other in a LIQUID substance

Gas

This is close up view of particle interactions with each other in a GAS substance

Introduction 2

• When heat is applied to a substance the heat energy is given to the atoms and they vibrate and move faster and so their kinetic energy increases.

• The vibrating atoms bump into neighboring atoms and pass on their kinetic energy. These atoms then pass on their kinetic energy to atoms close to them and so on. In this way the heat energy moves through the substance.

Open Ended

Atoms in a substance are always _________

Multiple Choice

When heat is applied to a substance the atoms vibrate and move __________ and so their kinetic energy ____________

• slower, increases

• faster, increases

• slower, decreases

• faster, decreases

How Thermometers Work

• Temperature is the measurement of the average kinetic energy of the atoms in a system.

• When you place a thermometer in the freezer, it loses heat to the surroundings because the thermometer is warmer and heat always moves from the hotter object to the colder object.

How Thermometers Work 2

• When the thermometer loses its heat, the molecules in the liquid slow down and the liquid contracts pulling its level lower on the thermometer scale.

• Place the thermometer in a warm environment and the atoms begin to increase in average kinetic speed the liquid expands and moves up the thermometer scale.

How Thermometers Work 3

• Digital thermometers still use thermodynamics to measure temperature.

• Instead of a bulb with liquid, digital thermometers use an invisible laser called infrared that scans and measures the average kinetic energy of the molecules in your body the same way a traditional one does

Reading

In our environment heat transfer is always from the hotter object to the colder object. Heat transfers to and through some materials better than others. In this lesson you will learn the three ways that heat transfers: conduction, convection, and radiation. 

Notes: Conduction

Conduction is the transfer of heat between substances that are in direct contact with each other. The better the conductor, the more rapidly the heat will transfer. 

Open Ended

What substances do you think would be good conductors? (What are some objects that get hot very easily?)

Open Ended

What substances do you think would be good insulators? (What are some objects that DON'T get hot very easily?)

Notes: Conduction 2

• Metals are the best solids for conducting heat.

  
  

• Metals have tightly packed atoms which can easily pass on their kinetic energy and also have free moving electrons.

  
  

• These electrons can move from the hot part of the metal to the colder part transferring the energy more quickly.

Notes: Convection

• Convection is the up and down movement of gases and liquids caused by heat transfer.

• As a gas or liquid is heated, it warms, expands, and rises because it is less dense. When the gas or liquid cools, it becomes more dense and falls.

Notes: Convection 2

• As the gas or liquid warms and rises, or cools and falls, it creates a convection current.

• Convection is the primary method by which heat moves through gases and liquids.

Open Ended

Can you think of some examples of heat convection?

Notes: Radiation

• When electromagnetic waves travel through space, it is called radiation. When electromagnetic waves come in contact with an object, the waves transfer the heat to that object.

• Electromagnetic waves travel through empty space. The sun warms the earth through the radiation of electromagnetic waves.

Open Ended

Can you think of examples of radiation heat transfer?

Open Ended

What are the three different types of heat transfer?

Multiple Choice

The transfer of heat between substances that are in direct contact with each other.

• Conduction

• Convection

• Radiation

Multiple Choice

The transfer of heat by movement of a heated fluid such as air or water.

• Conduction

• Convection

• Radiation

Multiple Choice

The transfer of heat by means of electromagnetic waves.

• Conduction

• Convection

• Radiation

Open Ended

What does temperature measure?

Multiple Choice

Heat always transfers from the

• hotter object to the cooler object

• cooler object to the hotter object

• hotter object, then the cooler object, then back into the hotter object

• cooler object, then the hotter object, then back into the cooler object

Open Ended

What did you learn from this lesson?