Unit 3 A Energy What is Energy Discuss

Unit 3 A- Energy

What is Energy? • Discuss: What forms of energy can you think of? How would you define energy? • #1 Use your terms list to define energy. • Energy can be defined as the ability to do work.

Work • I work at Ramstein middle school. You work on your homework. Your dad does some work in the kitchen. Your sister works at the BX. • This is how we normally think of work in our everyday lives. But, the scientific definition of work is completely different!! • Let’s read together from page 570 in the textbook

WORK • #2 Define work as it is defined in your terms list. What unit is used to measure work? • Work is done on an object if force is used on the object AND the object moves a distance in the same direction that the force was applied • Work is calculated as force x distance • Let’s play a game… Is this work? ?

Is this work? • Student A uses force (push, pull, lift) to do work on Mrs. Naglack’s mini-fridge. • Student B lifts a book over his head. Did he do work? • Student C pushes as hard as she can against the wall. Was work done? • Student D runs around the classroom. Did he do work? • Student E picks up a book and carries it around the classroom. When was she doing work?

Calculating work Work is calculated as force x distance The unit for work is a Joule The unit force is a Newton The unit for distance must be in meters A Newton is roughly the force that is need to lift an apple • So…. . Lifting one apple, one meter = 1 Joule • 1 N x 1 m = 1 J • • •

Let’s Practice • Allen used 80 N of force to move a box 1 meter. What amount of work was done? – 80 N x 1 m= 80 Joules or 80 J • Trisha used 10 N of force to move a textbook 10 m. What amount of work was done? – 10 N x 10 m= 100 J

Potential v. Kinetic Energy • Remember --- Energy is needed to do WORK • Discuss: Does a rock resting at the top of a hill have energy? Does a rock rolling down a hill have energy? • YES!!!!!! • The rock resting at the top of the hill has potential energy. The rock rolling down the hill has kinetic energy.

Potential Energy/ Kinetic Energy

Poor little man!

How much?

Let’s Sing! Yes…. . This is happening! • https: //www. youtube. com/watch? v=vl 4 g 7 T 5 g w 1 M&t=1 s

Energy Transformation • Energy is the ability to do _______ • Energy is neither created nor destroyed, this is known as the _____. Energy just changes from one form to another. • Let’s look take a look at Mechanical Energy!

Mechanical Energy • Mechanical energy is energy due to the motion and position of an object. • ME = KE + PE (kinetic energy + potential energy) • If you are a student and…

you ask a teacher about mechanical energy, she is going to show you some roller coaster…

If you ask her how to calculate mechanical energy, she is going to talk about mass and speed… • Discuss: If a race car is travelling at a speed of 9 meters per second a baseball is thrown by a pitcher at 45 meters per second. Which has more mechanical energy? WHY? • The race car has significantly more mechanical energy because it has more mass.

Once she tells you more about mass, she is going to compare it to weight… • #4 Define mass. • Mass is the measure of an object's resistance to acceleration (a change in its state of motion) when a force is applied • Discuss: What is the difference between mass and weight? Are they the same? • https: //www. youtube. com/watch? v=gjf. LI 7 a. JKm. Q • https: //www. youtube. com/watch? v=PEQz. Abiz. M Ys

Since she is still defining mass, she will definitely talk about matter… • We defined mass earlier as the amount of matter in an object. SOOOOOO… now what is matter? ? • Matter is everything around you…. matter is ANYTHING that has mass and takes up space

When she talks about matter, she WILL mention atoms…. • All matter is built by building blocks called atoms. These atoms are also made of matter! • Discuss: What do you already know about atoms? • Atoms are made-up of protons, neutrons and electrons. These particles are called subatomic particles. Sub= below Let’s take a look

Calcium Oxygen

When she tells you about atoms, you will probably ask how small they are… • https: //www. youtube. com/watch? v=y. QP 4 UJh Nn 0 I

Once you find out how small atoms are, you will need to know that they bond together… • When atoms combine, they form molecules. • Let’s look at the molecule for sugar –YUM! • http: //www. ducksters. com/science/molecules. php

Now that they are bonding together, they will form more matter… • And since they are matter, then they will definitely have mass and, therefore, effect the amount of mechanical energy in an object.

Mechanical Potential Energy • The energy an object or system has due to its POSITION.

Types of Energy

Mechanical Kinetic Energy • The energy of an object or system due to its MOTION.

Radiant or light Energy • Radiant energy is the energy carried by electromagnetic waves. The type of energy from the sun. • Radiant = Light (but it isn’t always visible) • Examples are light, sunlight, x-rays, UV light (invisible)

Chemical Energy • Chemical energy is potential energy

Electrical Energy • Discuss: When do we use electrical energy? What would happen if the electricity went out at our school? Describe how electrical energy works (use your terms list to help you)

Electrons on the move • Current electricity is negatively charged electrons moving along a closed circuit. We will discuss a lot more about electrical energy in unit 3 B.

Nuclear Energy • Nuclear power plants use the heat released from fission to make electricity. By splitting uranium atoms into two smaller atoms, the extra energy is released as heat.

Thermal (Heat)Energy • Heat energy comes from rapidly moving molecules. Heat transfers from…… • As we learned in the last unit, heat transfers by conduction, convection and radiation.

Conduction, Convection or Radiation

Sound Energy • Sound energy is the energy produced by vibrating sound waves

Magnetic Energy • Energy causing a push or pull

Gravitational Energy • Energy of place or position

Elastic Energy • Potential energy stored in objects that are stretched

The Law of Conservation of Energy • Discovered and documented in 1840 by James Joule • The Law of Conservation of Energy states: Energy cannot be created or destroyed. It can only be transformed from one form to another.

Energy Transformation • Transform means to “change”… • • Energy can be changed from one type to another. For example, as water falls over a waterfall, its gravitational potential energy is first transformed into kinetic energy

Energy Transformation • Discuss. . Looking at the types of energy on your terms list, how is energy being transformed when… – A kid kicks a soccer ball – A kid slides a book across the table – Water backs up behind a dam - A plant sits in the sun - A toaster makes toast

What’s the energy transformation? • A cell phone ringing – Electrical to sound (ringing – vibrations) & chemical (battery) & thermal (heat) &kinetic (vibrating), radiant (lights) The sun giving energy to an apple tree so it can grow. - Radiant to chemical Gasoline making a car run - chemical to mechanical (kinetic) Hair dryer drying your hair - electrical to thermal & sound

#8 • Write down 10 or more energy transformations you have in your home! • Only 5 transformations can begin with electrical!!!!