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This can be a bit tricky but below are a few ideas to help spark your creativity:
- Decide on the last step of your machine. It may be something useful or wacky.
- Gather some items from around the house, such as balls, marbles, dominoes, string, toy cars, magnets, cardboard or tubes, etc. Don't worry, you can collect more later.
- Now play with the items you gathered. What can the car bump into or knock down? Can the string pull something up or down? What can push the ball down the cardboard ramp? Have fun with this!
- Get a piece of paper and start brainstorming any idea that pops into your head. No matter how crazy the idea seems, write it down for later. Even if you don't use it, it may help you think of more things. Trouble brainstorming? Then try this. Write down 20 uses for a roll of tape (other than its intended use). It can be anything, as silly as you want.
- Once you feel you have some good ideas for your machine, sketch out simple pictures so that you can see the steps. Don’t forget to label the energy transfers to help you later
- As you begin assembling your machine and running trials, REMEMBER that it is okay to make changes! Plan on making quite a few changes as you learn what works best.
- If you get stuck at a certain step of your machine, maybe try thinking backwards? Start at the last step, and connect the part to it that triggers it. Or take a break away from the machine... sometimes you'll come back with a fresh solution to the problem.
This can be a bit tricky but below are a few ideas to help spark your creativity:
- Decide on the last step of your machine. It may be something useful or wacky.
- Gather some items from around the house, such as balls, marbles, dominoes, string, toy cars, magnets, cardboard or tubes, etc. Don't worry, you can collect more later.
- Now play with the items you gathered. What can the car bump into or knock down? Can the string pull something up or down? What can push the ball down the cardboard ramp? Have fun with this!
- Get a piece of paper and start brainstorming any idea that pops into your head. No matter how crazy the idea seems, write it down for later. Even if you don't use it, it may help you think of more things. Trouble brainstorming? Then try this. Write down 20 uses for a roll of tape (other than its intended use). It can be anything, as silly as you want.
- Once you feel you have some good ideas for your machine, sketch out simple pictures so that you can see the steps. Don’t forget to label the energy transfers to help you later
- As you begin assembling your machine and running trials, REMEMBER that it is okay to make changes! Plan on making quite a few changes as you learn what works best.
- If you get stuck at a certain step of your machine, maybe try thinking backwards? Start at the last step, and connect the part to it that triggers it. Or take a break away from the machine... sometimes you'll come back with a fresh solution to the problem.
The following video is simplistic in the basics of kinetic and potential energy, but explains them well. https://www.youtube.com/watch?v=rWANt3-MYjU&t=1s
This is a bit of a review of kinetic and potential energy, but also lists some of the other various labeled forms of energy. https://www.youtube.com/watch?v=_8EEnMwkmZk
This website provides links to explore the main types of simple machines. https://www.polk.k12.ga.us/userfiles/674/simplemachinespresentation1.pdf
This provides a nice explanation of the various forms of energy and how they are transformed. https://www.ck12.org/book/ck-12-fourth-grade-science/section/1.3/
This is a simple video providing some basics which should help as you explore the energy transformations within your own machine. https://www.youtube.com/watch?v=ftj23FRS2LI
Think about what is happening right before the energy transformation and right after the energy transformation.
- Before the transformation… What type(s) of energy is(are) present?
-- Is there acceleration? Velocity?
-- What is about to change, and how?
- After the transformation… What type(s) of energy is(are) present now?
-- Was there a change in velocity? Acceleration?
- If you need an approximate mass, try to find it on the internet. *Remember* to copy and paste the link to the website you obtained your estimated value from somewhere on your worksheet. Include a sentence next to it stating that the link is for your estimated value of ___________ units.
To calculate this ratio, you will need to first calculate your input and output energy for the energy transfer (see “How do I calculate the input and output of the energy transfer?”). Then, using those values, divide your calculated output energy by your calculated input energy.
The exact equation can vary depending on the type of energy that is your input. To find your equation, think about these questions and refer back to the Video Assessment Worksheet we completed with Mr. E in class today.
Is your machine a closed system or open system? (Is the energy leaving your machine?)
Will the total energy, or the value (in Joules) be changing? (E)
What type of energy is the input? What type of energy is starting the transfer?
What type of energy is the output? In the instant after the transfer, what type of energy does the system have?
You don’t have to have values, or actual numbers, for these equations. Just labeling the type of energy going in and coming out… your input and output energies will be good enough.
That depends on the situation and the system at which you are looking. Energy transfers can stop, for example, if you have a car accident. There is a transfer of energy between the cars in the collision. The involved cars become the system. The total energy of the system will end up being equal to zero. This happens as the objects within the system (cars) eventually come to a stop. The energy did not disappear, but rather it is transferred outside of the system. It can be transferred as heat and sound. The tires skidding on the road create a lot of resistance. Evidence of the high resistance would be the skid marks left after the accident. Because of the objects outside the system creating resistance, energy from within the system must do work. The cars are continuously transferring energy out of the system until there is not enough energy left within the system to continue to move either car. Then, the energy has all been transferred out of the system and the transfer stops. The energy has traveled to other objects.
If you are looking at a system like the cells in our bodies, or humans on Earth, then no, there is always some sort of energy transfer going on somewhere. Keep in mind that energy is never created or destroyed (Law of Conservation of Energy). It simply changes from one form to another.
Great question!!
As in the example above, it depends on how you look at it. The transfer of energy between the cars in the accident begins the instant they contact each other. But when it ends can depend on what part of the situation you are looking at. If you are someone who designs airbags, and want to know about just the two cars involved, and nothing else, then you look at the instant when they hit and the immediate before and after. Since you are not concerned about all the skid marks, or the road sign, or whatever else they may have encountered after they hit each other, your “end” of the energy transfer is the second right after the initial collision of the 2 cars. You would calculate your equations based on just that moment in time. If you are the police person in charge of investigating the scene, then your “end” of the energy transfer would encompass the whole collision and all the objects involved until the vehicles weren’t moving.
Yes, it can in a sense. Through waves would be an example. Say, for example, you are standing in front of a giant speaker at a concert.. That is an energy transfer from the speaker to you, but the source did not physically touch you. The air carried the energy to you. Technically, it would still be one type of object touching another (molecules of the gases that make up air touching your skin) but it depends on how you look at it. The air touches you but the source didn’t. Did you know If you are in the vacuum of space, where there is no air, you cannot make any sound!?! Another good example is heat. If you stand in the sun on a clear day, the warmth you feel is heat energy. The sun isn’t touching you, but you are receiving its energy, which is strong enough to burn you too, so touch doesn’t relate to the strength, or magnitude of the energy. Plants use this touch-less energy when they convert sunlight into food energy during photosynthesis. They are using the energy in sunlight and converting it to food.
To calculate an energy transfer, you need an input and output energy.
What type of energy is your input? Output?
What are the equations for those energies?
Is your system closed or open?
Will you have a change in total energy? (E)
It is ok if you don’t have values in your equation. If you label the type of energy going in and out, that is fine.
If you do not have actual values, and you are just labeling the types of energy for input and output, then some of your labels will probably be the same.
You probably won’t get to “play” much with air resistance because it is dependent on so many variables. It is a type of friction that depends on air density or pressure, the surfaces of the objects involved, velocities, along with some other things… It's a lot to try and factor in. In classes like this and a lot of the ones offered in college, air resistance is omitted to simplify the process of solving the equations. It is more important to know how energy works. If you understand that, and you need to know air resistance, it’s just a handful more calculations to throw in that you will learn down the road if it’s needed at your job or something.
As for friction, you should encounter that in class a little bit, if you haven’t already (static friction and kinetic friction). If you are interested in it, I found an intro on page 154 of your textbook. There are also some great videos out there, including ones I found on Khan Academy, starting with this link: https://youtu.be/TC23wD34C7k
Here is a site that is FULL of info for both air resistance and friction: https://www.physicsclassroom.com/class/newtlaws/Lesson-2/Types-of-Forces
This energy would be in the form of vibrations in the air caused by sound waves. You could find the total energy created by the sound waves by finding the total energy required to move the object in the path of the waves… or, if I remember correctly from the video, the soccer ball.
Wheel and axle: is the wheel spinning your input or output?
Have you learned about rotational energy, or circular motion?
Imagine your wheel has a nice flat edge and you are looking at it from the side, like the wheel of a car. You set a marble on the top, perfectly in the center and it doesn’t roll off. It stays still. If you slowly begin to rotate the wheel, what happens to the marble? What type of energy does the marble end up with?
If the wheel is your output, imagine that there’s a wheel in front of you. It isn’t rotating. You place your fingers on it and spin it. What type of energy were your fingers using to move the wheel?
Wedge: think about what is happening each step of the way as your wedge does what it needs to do in your machine. Is the wedge moving? How is it moving? What type of energy does this motion resemble?
Next… what is the outcome of the wedge’s motion? Is it splitting or forcing something open? What kind of energy would you say is occurring in the outcome? Think of the edges of the wedge as hands pushing on an object.