ENERGY
Energy is the ______ to _______
ability, change
What form of energy does the sound of a TV have and explain why?
acoustic, movement through sound waves/vibrations makes the sound of the TV.
Explain the difference between an open and closed system
an open system is one that exchanges BOTH matter and energy with the surroundings. Matter and energy comes and goes. A closed system is one that exchanges ENERGY but NOT MATTER with the environment.
Explain all of the changes in PE and KE when you swing on a swing.
as you are swinging back you have Ke but the PE is building. At the top of the backswing, the PE increases and the KE decreases. As you swing down, the KE increases and the PE decreases. AS you go into the up-swing, the PE increases and KE deceases. You then swing back down and the KE increases and the PE decreases. IT ALL STARTS OVER AGAIN.
Why is sound categorized as energy?
b/c it does not have a mass and does not take up space. You cannot hold onto sound.
Compare matter to energy
both cannot be created or destroyed. Matter has a mass and takes up space, but energy does not have a mass and doesn't take up space.
Food is what type of energy?
chemical
When you are baking cookies, heat is involved. What form of energy is in the cookies?
chemical
What form of energy does baking cookies have and explain why?
chemical and thermal, (chemical) stored energy in the atoms of the ingredients of the cookies, (thermal) total energy of the molecules moving gives off heat.
When I am making a fried egg, what type of heat transfer is occurring on the bottom of the egg?
conduction-heat transfers from the pan to the egg
When I take a cake out of the oven, what type of heat transfer occurs?
convection-heat transfers throughout the atmosphere.
When energy is used, it is not _________ or ________. It can be transferred from ______ form to _______
created, destroyed, one, another.
What form of energy does plugging in an iron have and explain why?
electrical, movement of electrons to provide electricity to power the iron.
Radiation tranfers thermal energy by __________________ Ex/
electromagnetic waves, ex/the Sun, fire, oven etc.
in #45, explain how this relates to the Law of Conservation of Energy.
energy is released, but its converted to another form of energy, so it is not lost. However, matter is also put into the atmosphere, so more energy is used and not conserved.
What form of energy does pushing a chair across have and explain why?
energy to move the chair.
True or False: The total amount of the energy in the universe changes from day to day. Explain your answer
false- the amount of energy always stays the same b/c energy cannot be created or destroyed. Energy just changes from one form to another, but each form is still energy.
Think of a fire, show the energy transformations. Also, explain if this is an open or closed system
fire is an open system. Chemical energy to Radiant + heat + acoustic (if you can hear the fire crackling)
Think of a flashlight that is battery powered, Explain the energy transformations that take place when you use a flash light. Be sure to also explain if this is an open or closed system
flashlights are closed systems. Mechanical energy (turning it on) to chemical energy (battery) to radiant (light) and thermal.
Convection transfers thermal energy in _______ Ex/
fluids ex/ heat circulating the air, heat in oven moving around, etc.
When energy is converted from one form to another, ________ is released as an unwanted form.
heat (thermal energy)
Explain how the Law of Conservation of Energy applies to you as your a mile around the track. Be sure to include all forms of energy that take place
humans contain chemical energy. As you run, you convert the chemical energy to mechanical energy and thermal energy. You could also have acoustic energy if you are breathing hard. The original chemical energy is converted not lost. The thermal energy is released into the atmosphere.
If the smart car was a much larger car, how would this scenario change?
if it was larger, it would probably have more mass. Therefore, it would have more mechanical energy to transfer to the other car. The car would move more b/c more energy would be transferred to it.
Compare energy transfer in an open system versus a closed system
in an open system more energy is exchanged from one form to another and b/c it also released matter. Open systems conserve LESS energy b/c they also exchange matter and energy. Closed systems conserve MORE energy than open systems b/c they don't exchange matter also.
When I use a toaster, what energy transformation take place? Include if this is an open or closed system and why
it is a closed system b/c it doesn't exchange matter with the environment. Electrical to mechanical to thermal and radiant to mechanical and acoustic and thermal.
If I am running I have ________ energy
kinetic
Heated air is ______ dense than cooler air. This is important in which type of heat transfer?
less
When objects push or pull on each other, they transfer ________
mechanical energy
What form of energy does the Sun have and why?
nuclear, radiant, thermal, (nuclear) the nucleus of the atoms split, (radiant) electromagnetic waves make the light from the sun, (thermal) total energy of the molecules moving gives off heat.
If a book is sitting on the table, it has _______ energy. As the book falls off the desk, what happens to the types of energy?
potential
Compare potential and kinetic energy
potential energy is stored energy and doesn't cause movement. Kinetic energy is the energy of movement. Potential energy converts to kinetic energy.
What form of energy are the waves from a microwave? What makes them different than any other form of energy?
radiant (electromagnetic) b/c we can't see them and they travel through empty space.
What form of energy does light from a flashlight have and explain why?
radiant, electromagnetic waves make the light from the flashlight.
You went to sit on a bench and it was really hot, what type of heat transfer has taken place to make the bench hot?
radiation-you don't ALWAYS need matter to be heated through radiation. For example, you can feel heat from a fire, without touching. You can feel heat from a stove also and do not need to touch it.
The amount of energy transferred from one object to another depends on:
the amount of mechanical the object causing the collision has - there mass and speed increases their mechanical energy
Explain how energy can be converted in a given system
the less transformations, the more energy that is conserved. To conserve energy, you need to make it more efficient by not having as many transformations.
Two people are on a roller skates facing each other. One has a mass of 200 lbs. and the other has a mass of 100 lbs. They both pull equally on each other. Explain in term of energy transfer and distance traveled what happens
the person that has more mass (200 pounds) would move the other person toward them b/c they would have more mechanical energy that could transfer. Meanwhile, that same person would move in the opposite direction b/c of the transfer of energy.
A smart car is backing up out of its driveway and hits a car behind it. The car that it hit moved a bit. Explain what happened thinking of energy
the smart car transferred mechanical energy to the other car, causing it to move. At the same time, the smart car may move in the opposite direction because there is always an equal and opposite movement.
Explain how a spring is both kinetic and potential energy. Be sure to explain the relationship between them.
the spring is pushed down (coiled up) it has more PE than KE. As the spring lengthens (pops up) the Pe is converted to KE and the KE increases while the PE decreases.
You are standing on the beach... explain how radiation, conduction, and convection transfers thermal energy. Be sure to include all parts!
the sun heats the sand through radiation, the sand transfers heat to your feet through conduction, you release heat through movement into the atmosphere and the heat moves through air by convection.
What is the product of ALL energy reactions
thermal energy (heat)
What form of energy does heat from a light bulb have and explain why?
total energy of the molecules moving gives of heat.
Conduction transfers thermal energy between ____________ Ex/
two objects, ex/ sand to your feet, oven rack to pan etc.
Explain how the Law of Conservation of Energy applies to cookie baking
when the cookies bake, some chemical energy is converted to thermal energy. The energy is not lost, but it just changes forms.
When you are on a diving board ready to dive, explain what would happen in regards to potential and kinetic energy as you dive into the water. Be sure to think of each step along the way.
when you are standing on the diving board, you have more PE than KE. As you dive into the air, your PE converts to KE, so the KE increases and the PE decreases. As you hit the water, you still have KE and PE, but the PE will begin to increase, while the KE begins to decrease.
Think of a wind turbine explain the energy transformations that occur from the beginning to thew end. Also, is this an open or closed system?
wind hits the turbine and it turns...mechanical energy converts to electrical + acoustic + thermal
Why is a table NOT energy?
you can get a mass of a table and it takes up space. It doesn't create change.
