Teaching Physical Science

This physical universe is composed of Energy and Matter

What is Physical Science?

All of physical science is simply understanding energy and matter and the reactions between them.

www.lmunet.edu/academics/physics/feed_back.htm

Matter

• Anything that has mass and takes up space.

What should elementary students understand about matter?

Matter

• The universe is made of matter. • Different kinds of matter has different

characteristics (properties). • Anything made of matter takes up space. • We often call different kinds of matter

“materials.”

Matter

• We can use our senses to describe materials (heavy, light, rough, smooth, hard, soft, elastic, firm, magnetic, not magnetic, conductor, insulator).

Picture from http://ladyfi.files.wordpress.com/2008/09/five-senses_vmo0128.jpg

Matter

• We can use tools to help us discover the properties of different kinds of materials.

• Some common materials are wood, plastic, paper, glass, metal, and cloth.

• The properties of a material determine how it can be used.

Matter

• Matter often exits in one of three states: solid, liquid, or gas.

• Common misconception: All matter is either solid, liquid, or gas. Wrong. There are also plasmas and various colloids (mixtures of different states).

Matter

• All matter has mass, which means that gravity pulls on it. The more mass something has, the harder gravity pulls on it.

• Higher level concept: Mass attracts mass. That is essentially what gravity is.

Matter

• Matter is made up of small particles too small to see. These particles move around all the time but because they are too small to see, we can’t see them moving.

Matter The physical state (solid, liquid, gas)

something is in depends on how fast the particles are moving.

In solids, the particles are moving slowly.

In liquids, much faster, and in gases, very very fast; so fast they may escape from the container they are in if it is open.

Matter

• How fast the particles move depends on how much energy there is in the system. “To heat” something means to add more energy (more movement) within the molecules. This can change the state.

Picture from http://www.grc.nasa.gov/WWW/K-12/airplane/Images/state.gif

Matter

• Heat: The amount of energy motion (kinetic energy) in the atoms or molecules

•  Temperature: Measure of the amount of kinetic

energy • Cold: In scientific terms, there is no such thing

as cold. More heat/less heat

Activity: Oobleck • More about Ooblick on this site: http://education.jlab.org/beamsactivity/

6thgrade/oobleck/index.html

Matter

• Atoms have mass, which means that gravity pulls on them.

• Common misconception: Mass and weight are the same thing. Wrong. Mass is the amount of matter in something; weight is the pull of gravity on the mass).

Activity: Spreadsheet Weight

Planet Weight Mercury 38 Venus 90 Earth 100 Mars 38 Jupiter 238 Saturn 92 Uranus 89 Neptune 113 Pluto 7 M oon 17

0

50

100

150

200

250

Weight

Weight

Matter

• Atoms can be combined in different ways (molecules).

• There are only a limited number of atom-types; these are combined in different ways to make all the matter in the universe.

• The nature of the molecules in matter determine the way it reacts with other matter (its chemical properties).

Matter

• When we observe physical changes, we change the shape or state of the matter, but we do not change the molecules that make up the matter.

• When we observe chemical changes, the

molecules are changing -- new combinations -- so after a chemical change you have new kinds of matter.

Matter • Matter behaves in predictable ways

everywhere in our universe. • The same (atoms, molecules) act the same

way under the same conditions. • Matter cannot be created or destroyed except

in a nuclear reaction where it can change into energy or be created from energy. The total amount of mater + energy in the universe is constant.

Understanding Energy

• What do elementary students need to know?

▫ Forms of Energy ▫ How some common forms of energy behave ▫ How energy can be converted from one form to another

Forms of Energy •  Thermal energy (heat) • Chemical energy • Electrical energy • Radiant energy (such as light) • Magnetic energy • Elastic energy •  Sound Energy • Mechanical energy • Nuclear energy

(Wikipedia, http://en.wikipedia.org/wiki/Energy_forms)

What do they need to know about thermal energy (heat)? • The internal motion of the atoms is called

heat energy, because moving particles produce heat.

• Heat energy can be produced by friction. • Heat energy causes changes in

temperature and phase of any form of matter.

Examples of when heat energy is involved

•  Phase changes • Water cycle •  Friction • Rock cycle •  Students need to understand what is happening.

Why are the particles moving (slower, faster)? How does this change the system?

Trace the heat energy in this system.

Picture from http://1to10reviews.files.wordpress.com/2007/06/water_cycle_01.gif

Chemical Energy

• Chemical Energy is required to bond atoms together.

• When bonds are broken, energy is released.

Chemical Energy

• Fuel, food, and batteries are forms of stored chemical energy.

Adapted from education.jlab.org/jsat/powerpoint/energy_forms_and_changes.ppt . Retrieved from the Internet on February 3, 2010.

Electrical and Magnetic Energy • What do students need to know? ▫  Static and current electricity ▫  Conductivity and insulation ▫  Circuits

▫  How magnets behave.

▫  That electricity can cause magnetism in some materials; that magnetism can cause electrical energy in some materials.

Let’s Make a Battery!

•  http://www.youtube.com/watch?v=o908BE8nUS8

• Explain how this works. Where is the energy? What kinds of energy?

Electromagnetic Energy

•  Light is a form of electromagnetic energy.

•  Each color of light (Roy G Bv) represents a different amount of electromagnetic energy.

•  Electromagnetic Energy is also carried by X-rays, radio waves, and laser light.

Adapted from education.jlab.org/jsat/powerpoint/energy_forms_and_changes.ppt . Retrieved from the Internet on February 3, 2010.

Nuclear Energy

• The nucleus of an atom is the source of nuclear energy.

Adapted from education.jlab.org/jsat/powerpoint/energy_forms_and_changes.ppt . Retrieved from the Internet on February 3, 2010.

Nuclear Energy

• When the nucleus splits (fission), nuclear energy is released in the form of heat energy and light energy.

• Nuclear energy is also released when nuclei collide at high speeds and join (fuse).

Adapted from education.jlab.org/jsat/powerpoint/energy_forms_and_changes.ppt . Retrieved from the Internet on February 3, 2010.

Nuclear Energy

The sun’s energy is produced from a nuclear fusion reaction in which hydrogen nuclei fuse to form helium nuclei.

Adapted from education.jlab.org/jsat/powerpoint/energy_forms_and_changes.ppt . Retrieved from the Internet on February 3, 2010.

Mechanical Energy

• When work is done to an object, it acquires energy. The energy it acquires is known as mechanical energy.

Adapted from education.jlab.org/jsat/powerpoint/energy_forms_and_changes.ppt . Retrieved from the Internet on February 3, 2010.

Mechanical Energy

• When you kick a football, you give mechancal energy to the football to make it move.

Adapted from education.jlab.org/jsat/powerpoint/energy_forms_and_changes.ppt . Retrieved from the Internet on February 3, 2010.

Mechanical Energy When you throw a balling ball, you give it energy. When that bowling ball hits the pins, some of the energy is transferred to the pins (transfer of momentum).

Adapted from education.jlab.org/jsat/powerpoint/energy_forms_and_changes.ppt . Retrieved from the Internet on February 3, 2010.

Energy Conversion

• Energy can be changed from one form to another. Changes in the form of energy are called energy conversions.

Adapted from education.jlab.org/jsat/powerpoint/energy_forms_and_changes.ppt . Retrieved from the Internet on February 3, 2010.

Two Categories of Energy Kinetic and Potential

• Kinetic Energy is the energy of motion. • Potential Energy is stored energy.

Adapted from education.jlab.org/jsat/powerpoint/energy_forms_and_changes.ppt . Retrieved from the Internet on February 3, 2010.

Kinetic Energy •  The energy of motion is called kinetic energy. •  The faster an object moves, the more kinetic

energy it has. •  The greater the mass of a moving object, the

more kinetic energy it has.

Adapted from education.jlab.org/jsat/powerpoint/energy_forms_and_changes.ppt . Retrieved from the Internet on February 3, 2010.

Potential Energy

•  Potential Energy is stored energy. ▫  Stored chemically in fuel, the nucleus of atom, and

in foods. ▫  Or stored because of the work done on it: �  Stretching a rubber band. �  Winding a watch. �  Pulling back on a bow’s arrow. �  Lifting a brick high in the air.

Adapted from education.jlab.org/jsat/powerpoint/energy_forms_and_changes.ppt . Retrieved from the Internet on February 3, 2010.

Gravitational Potential Energy

•  Potential energy that is dependent on height is called gravitational potential energy.

Adapted from education.jlab.org/jsat/powerpoint/energy_forms_and_changes.ppt . Retrieved from the Internet on February 3, 2010.

Potential Energy

•  Energy that is stored due to being stretched or compressed is called elastic potential energy.

Adapted from education.jlab.org/jsat/powerpoint/energy_forms_and_changes.ppt . Retrieved from the Internet on February 3, 2010.

Gravitational Potential Energy

•  A waterfall, a suspension bridge, and a falling snowflake all have gravitational potential energy.

Adapted from education.jlab.org/jsat/powerpoint/energy_forms_and_changes.ppt . Retrieved from the Internet on February 3, 2010.

The Law of Conservation of Energy

• Energy can be neither created nor destroyed by ordinary means. ▫  It can only be converted from one form to another. ▫  If energy seems to disappear, then scientists look

for it – leading to many important discoveries.

Adapted from education.jlab.org/jsat/powerpoint/energy_forms_and_changes.ppt . Retrieved from the Internet on February 3, 2010.

Teaching about Energy

•  Teach students to: ▫  Identify the kind of energy involved ▫  Know the basic characteristics of that kind of

energy ▫  Understand that energy can be converted from

one form to another ▫  Trace the energy through the system

Teaching about Force

•  Force is simply a description of what the energy is doing (usually pushing and pulling). Force is energy + direction.

•  Students learn that a force is a push or a pull, but they need to understand that we are talking about putting energy into the system.

Simple Machines •  There are many excellent resources available for

teaching simple machines. Teaching students to recognize simple machines and to identify then within more complex machines is important; however, remember the “Big Picture.”

•  Simple machines do not make the work “go away.” Remember the conservation of energy. Just as much energy must be put into a system to do the work whether a simple machine is used or not.

Simple Machines

• Using a simple machine makes the work EASIER to do by:

▫  Changing the direction of the force, ▫  Multiplying the force, ▫  Transferring the force from one place to another,

or ▫  Increasing the speed of a force.

Simple Machines

•  In other words, they organize the job so that there is less friction and so the direction, distance, and other elements of the force work most efficiently with how we do work.

• Help students not only identify the simple machines, but to understand what they change that makes work easier.

Simple Machines: Examples • A wheel works by reducing friction. Without the

friction, less energy is needed to do they work. • A lever works by allowing distance to take the

place of force (less force needed because a bigger distance is used). It’s a trade-off, but one that makes the work easier.

•  The wedge or inclined plane similarly trades

more distance for less force.

The Point!

• Remember: Memorization is not enough. Students must understand.

• Ask higher level questions. • Make sure students understand the Big Picture. • Matter and Energy. Refer to them often. They

are the twin concepts that form the universe.