Mr. Lambert Integrated Science 1A Trimester 1, 2014 Day 9 – Systems Mr. Lambert Integrated Science 1A Trimester 1, 2014

Bell Ringer – Monday, 10/27 What is the primary form of energy present in human bodies? (think about all that food we eat) When a human or animal dies, what type of energy does that energy transform into? What happens to this new form of energy?

Agenda Bell Ringer Reading review Systems Kinetic & potential Exit Slip

Learning Targets On your Bell Ringer Sheet, write the following: We will predict changes in the energy of a controlled and uncontrolled system

Review reading Why do some people believe that conservation of energy supports the existence of ghosts?

Review reading What is conservation of energy? Energy cannot be created or destroyed Energy can only change from one form to another The total amount of energy in an isolated system remains constant ("is conserved")

Review reading Why does the conservation of energy NOT support the existence of ghosts?

What is a system? An area of space that we choose to study. Bouncing basketball will eventually lose energy to surroundings

Uncontrolled system Copy this down! System that freely exchanges energy with its surroundings until it reaches a uniform energy distribution Examples: hot water in a pot, river

Controlled system A system where we control how the energy transfers. Copy this down! A system where we control how the energy transfers. Examples: Thermos, dams, spotlight

Controlled or Uncontrolled? In your group, decide whether the following scenarios are controlled or uncontrolled systems: Lit candle in the middle of a room Strong laser pointed at the same spot Piece of coal after the fire dies out Boiling water on my stove Uncontrolled Controlled

If I put boiling water in an open cup and boiling water in a thermos, which will keep the water hot longer? Thermos What happens to the thermal energy of the water in the cup? What about the thermal energy of the water in the thermos? Cup – The thermal energy enters the atmosphere Thermos – The thermal energy stays in the thermos 3. What happens to the total energy of the water in the cup? What about the total energy of the water in the thermos? Cup – The total energy decreases Thermos – The total energy remains constant

Kinetic & potential energy https://phet.colorado.edu/en/simulation/energy-skate-park If this were an uncontrolled system, what would happen to the thermal energy? It would escape into the environment! Look at the total energy of the skater. If this were an uncontrolled system, what would happen to the total energy? It would decrease

Potential Energy -- Notes Copy this down! Equation: 𝐺𝑃𝐸=𝑚∙𝑔 ∙ℎ To increase energy: _____________ the mass _____________ the height

Potential Energy -- Practice In each pair, which has the most GPE? 100 kg Boulder 10 meters high OR 100 kg boulder 5 meters high 30 kg weight 3 meters high OR 200 kg weight 2 meters high

Kinetic Energy -- Notes Copy this down! Equation: 𝐾𝐸= 1 2 ∙𝑚∙ 𝑣 2 To increase energy: _____________ the mass _____________ the velocity

Kinetic Energy -- Practice In each pair, which has the most KE? 10 kg sled moving at 10 m/s OR 10 kg sled moving at 12 m/s 100 kg boulder rolling at 20 m/s OR 50 kg boulder rolling at 100 m/s

Object Mass Height Final Velocity Baseball 145 g 2 m 6 m/s Basketball 624 g 1 m 4 m/s Shot Put 7,260 g 3 m 8 m/s Bowling Ball Does the basketball or the bowling ball have more kinetic energy? How do you know? Does the shot put or the bowling ball have more potential energy? How do you know?

Formative assessment handout 1. Read the scenario below and identify how the energy is being transformed from one form to another. The power has gone down in my house so I fill my generator with gasoline. I turn on my generator and sit on the couch to watch some tv. 2. The spring toy starts with 80 Joules of spring potential energy. When it is ½ way up, what types of energy does it have? How many joules of energy does each type have? 3. If a man jumps out of a plane and pulls a parachute, how would you describe the kinetic energy? How would the kinetic energy be different if the man’s parachute didn’t open? 4. You are on a swing. At what point do you have the most potential energy? At what point do you have the most kinetic energy? 5. Rub your hands together. Why don’t your hands stay hot? What happens to the thermal energy? 6. What are two ways you can increase the gravitational potential energy of an object? What are two ways you can increase the kinetic energy of an object?

Conservation of energy http://www.youtube.com/watch?v=mhIOy lZMg6Q

Exit Slip If you increase the height of an object, what happens to its gravitational potential energy? If you decrease the velocity of an object, what happens to its kinetic energy? In an uncontrolled system, will the energy all stay in one place? Why or why not?