A 2.01 -- Matter 1

2.01 PowerPoints There are 3 PowerPoints in this

packet. Matter Physical Changes Energy & Heat Transfers

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Matter

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Matter A pure substance or a mixture Composed of one or more elements that

are displayed on the periodic table The periodic table; a tabular way to

display all known chemical elements To provide a framework to classify and

compare chemical elements Food is matter

A 2.01 -- Matter

Physical Changes

Food is matter-A pure substance or mixture

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Physical properties Thermodynamics -- effect of change in

temperature, pressure, and volume (canning) Heat transfer -- the passage of thermal

energy from a hot to a cold body (cooking and cooling)

Microwave -- passing microwave radiation through food and water, fat, and sugar so they absorb energy (cooking)

Texture Appearance

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Why study physical changes?

Physical changes are crucial in: Product development Process design Shelf life

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Physical changes to matter

Physical changes to matter involve: Changing shape/size – crushing ice Changing temperature – boiling ice Changing phase – melting ice

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Changing its Shape or Size

Chopping Slicing Mashing Grinding

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Changing the Temperature

Change the temperature of matter without changing its chemical identity – heating and cooling.

Examples include pasteurization and rapid cooling.

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Changing Phase: Three states of matter are:

Solid -- ice Liquid -- water Gas – steam

Physical change in the state of matter that does not change the molecular structure.

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Changing Its Phase Phase is a physical

change in state of matter that does not change the molecular structure.

The three states of matter – solid, liquid, and gas.

A 2.01 -- Matter

Energy and Heat Transfer

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What Is Energy?

Types of energy Mechanical Chemical Electrical Radiant Nuclear

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What makes a machine to perform work.

Examples include: Hand mixers Water wheel Flour mill

Mechanical Energy

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Chemical Energy As bonds break or

form between atoms, chemical energy is generated.

Examples include: Using ice and salt

to make ice cream. Digestion of foods.

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Electrical Energy Movement of electrons Transported through wires

to where needed. Easily changed to heat or

mechanical energy. Examples include:

Electrical home appliances – stove, refrigerator, dishwasher

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Radiant Energy Energy transmitted

in the form of waves through space or some medium.

Examples: Microwave oven Sun Charcoal grills Gas flames

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Nuclear Energy Splitting or combining

atoms of certain elements which give off radiation.

Examples: X-rays in medicine Nuclear power Irradiation – food

preservation

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What Is Heat? Definition – An energy transfer

from one body to another caused by a temperature difference between the two bodies.

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Three Ways Heat is Transferred

Conduction Convection Radiation

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Conduction

Heat (or energy) is transferred by molecular collisions.

Example: Cooking foods in an

oven.

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Convection

Heat (energy) is transferred through molecular collisions and and currents.

Heat (energy) is more rapid than conduction.

Example: Food cooked in boiling

water.

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Radiation Heat (energy)

is transferred by light waves through space.

Examples: Sunlight Microwave

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