+

Day 4 – Spring, potential, kinetic energyMr. LambertIntegrated Science 1ATrimester 1, 2014

+ Bell Ringer

How does the roller coaster today get up to its highest point? (think about the beginning of the ride)

Does it cost more to lift the roller coaster if it is full of people?

+Agenda

1. Bell Ringer

2. Conservation of energy

3. Spring potential energy lab

4. Exit Slip

+Learning Targets

On your Bell Ringer Sheet, write the following:

We will relate kinetic, spring, and gravitational potential energy to conservation of energy

+Law of conservation of energy

The total amount of energy in a system remains constant ("is conserved")

Energy cannot be created or destroyed.

Energy can only be changed from one form to another

+Conservation of energy

 It is impossible to convert one form of energy into another without wasting some energy.Example: Automobile engines typically waste more

than two-thirds of the total energy used, primarily through heat.

In an isolated system, the energy will remain constant.

Example: Thermos, cooler

+Reminder…

Kinetic energy – energy of movement

Potential energy – energy that is stored

+Spring potential energy lab

Answer questions 1a and 1b.

+ KE = Kinetic Energy

m = mass

v = velocity SPE = Spring Potential Energy

k = spring constant

x = amount of stretch or compression

GPE = Gravitational Potential Energy

m = mass

g = gravity (9.81 )

h = height

+Fill in the data!

Trials Mass (kg)

Velocity (m/s)

Height (m)

GPE at peak height (J)

KE just after popping (J)

1          

2          

Student fill in data

How do we get these values? (next slide)

Trial 1 = no coin, Trial 2 = one coin

+Using the formulas

Example: Mass = 5 kg Gravity = 9.81 Height = 10 m

GPE = (5 kg) x (9.81 ) x (10 m)

Example: Mass = 5 kg Velocity = 14

KE = x (5 kg) x (14 2

Units for energy are Joules (J)!

+

Answer questions 5a, 6a, 6b, 6c, 6d

+Read #7 on pg. 373 – 374 and fill in the tablePosition

above table (m)

SPE (J) KE (J) GPE (J) SPE + KE + GPE (J)

At rest on table:Height = 0 m

       

Just after popping:Height = 0 m

       

Half way up:Height = _____

       

At peak:Height = _____

       

Each group will go up to the chalkboard and draw a diagram

+ Energy, Money & Conservation of energy

Think of the different types of energy as different types of coins (pennies, dimes, quarters). If you have $5 in quarters in a bowl, and replace one quarter with 25 pennies, how much money is in the bowl? What if you replace two quarters with 10 nickels?

The energy in a system can vary from kinetic, to gravitational potential energy to spring potential energy, but the total amount of energy would be the same (CONSERVATION OF ENERGY!!)

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1.When does the toy have the most SPE?2.When does the toy have the most GPE?3.When does the toy have the most KE?4.What kind of energy does the toy have when it is halfway up in

the air?

Look on pg. 375

+Look on pg. 375

+Quick Reading

Read the first three paragraphs on page 375 and answer the following questions in your notebook:

1. Even though energy changes from one form to another, what happens to the total energy?

2. Why doesn’t a bouncing ball reach the same height every time it bounces? Why does this still support the conservation of energy?

Demo: energy of a basketball

+Post-lab questions:

Answer questions 4, 6, 9, and 10

Challenge # 7, # 8

+Exit Slip

1. A “pop-up” toy has 2 Joules of spring potential energy before popping. How much kinetic energy will the toy have just after leaving the table?

2. Why can the second hill of the roller coaster not be higher than the first hill?

3. When the “pop-up” toy is flying up into the air, what types of energy does it have?