IntoScience Aims:
In the first lesson, we looked at forms of energy.
During this lesson we also covered the different ways energy can transfer from one object to another. These different ways are conduction, convection and radiation.
Conduction is the passing of energy from one solid object to another. This occurs when you touch a hot object. The object passes its energy directly into your hand. Convection is similar to conduction, however it doesn't occur in solid objects. Convection can only occur in gases and liquids. When one part of a glass of water is heated and the others aren't, the hot water will rise to the top because its increase in energy made it less dense than the rest of the water. These 'convection currents' can also occur in gases. Radiation travels as waves rather than as particles and can therefor travel through a vacuum. Examples of radiation are ultraviolet and infrared. We feel the latter as heat. Lesson Summary:
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Sankey Diagrams Aim: To create Sankey diagrams to describe energy transfers. Keywords: Transformation, Efficiency Energy Transfer: The movement of a single form of energy from place to place, or one body to another. Energy Transformations: The change of one form of energy into another form of energy. Focus Question: "How do we illustrate energy transformations?" Energy transformations can be recorded and illustrated using a Sankey diagram. A Sankey diagram is a scaled chart in which the width of the arrow corresponds to the amount of energy. Looking at the example below, first we note that each square has a value of 100J. This means that with the size of the input arrow being 12 squares wide, the input energy is 12 x 100 = 1200J. In a Sankey diagram, the useful energy is represented by an arrow to the right, and any energy wasted is represented with an arrow dropping down from the input energy. The width of the body of the arrow on the right is 9 squares wide. This equates to a total of 900J of useful energy produced.. We also notice the smaller arrow on the bottom. This arrow has a width of 3 squares wide. This means that a total of 300J of energy is lost. Now if we use the formula located at the top of the worksheet, which we also covered last lesson, we can calculate that 900J of useful energy divided by 1200J of input energy, multiplied by 100, is 75. This means that the kettle has an energy efficiency of 75%. Lesson Summary
Energy Transformations Aim: To describe what happens when energy is 'used.' Keywords: Energy, Potential, Kinetic, Heat, Light "Energy can be neither created or destroyed, it transforms from one form to another." This example of a roller coaster, shows the transformation between gravitational potential energy and kinetic energy. Gravitational potential energy increases as the subject ascends above ground level. This means that when the cart is at the starting point of the roller coaster, the highest point above ground level, it contains the most amount of gravitational potential energy. Once the cart reaches the bottom of the drop, all of its gravitational potential energy has been transformed into kinetic energy. This gives the cart the momentum to reach the next hill. The cart doesn't receive any energy after the beginning, meaning that each hill has to be slightly lower than the previous, as some energy is lost to air resistance. The cart doesn't fall in the loop, because the carts kinetic motion energy is strong enough to keep the cart in forward motion, rather than fall due to gravitational energy. Finally, the cart loses all of its energy due to the opposing forces of friction and air resistance. We also learnt how to calculate energy efficiency. The formula for this, as seen in question 3 on the worksheet, is the amount of useful energy output (measured in joules,) divided by the energy input, multiplied by 100. An example of this, as seen in question 3a on the worksheet, is the toaster. For every 500J the toaster uses to run, 450J are transformed into heat energy and 50J are transformed into light energy. This can be written as (450/500)*100, (see question 3a.) This works out to be 90, meaning that the toaster has an energy efficiency of 90%. Lesson Summary
Investigating Energy Aim: To investigate how to make a cotton reel car move, using potential energy. Keywords: Elastic Potential Energy Elastic: Any object that is able to be deformed and returns to it's original state. In this lesson we investigated how the elastic potential energy stored within a rubber band is able to make a car move. We also investigated how elastic potential energy is able to cause a rubber popper to jump into the air. Rubber Poppers Our experimentation with the rubber poppers found that if placed on a surface, the elastic potential energy stored within an inverted popper was enough to cause it to fly high in the air. This is because rubber will revert back to it's original shape if it is deformed. The elastic energy released from this motion is converted into kinetic energy that launches the popper into the air. Cotton Reel Car The construction of the cotton reel car demonstrated how objects don't need to be turned inside-out in order to contain elastic potential energy. The energy stored in the rubber band increased as it was twisted. The longer it was twisted the more energy that would build up and the faster and further the car would go. This also meant that too much energy caused the car to spin uncontrollably.
Lesson Summary:
Forms of Energy (energy/ˈɛnədʒi/ - The property of matter and radiation which is manifest as a capacity to perform work - Oxford Dictionary) Aim: To distinguish between forms of energy and sources of energy; and to classify the different forms of energy. Keywords: Kinetic, Potential. Focus Question: This week we consider the key question "What is Energy?" “Energy is the ability to do work.” Energy is the property that all matter has that allows it to have an impact on its surroundings. This can mean pushing an object, releasing heat into the environment or creating sound waves for example. Energy can be classified according to its properties, however all energy comes from a source being an object that originally contained the energy. Energy can be classified as either forms of energy or sources of energy. Sources: Sources of energy are where we get the energy from, and include:
Energy can be classified as either kinetic or potential. Kinetic energy is that energy associated with the movement of particles. Potential energy represents an object with the ‘potential’ to release energy. Kinetic and Potential energy can then be further classified into sub-categories such as those outlined in the table below: Lesson Summary:
Learnt about energy and the sources and forms of energy. Established the basic form and outline of our blog updates. Discussed and worked out our roles. |
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