Types of Energy

Potential Energy: A type of energy that is stored.  It is not actively being used but it can be converted to Kinetic energy when its being used.

• A car that is not moving but has a full tank of gas, a bouncy ball sitting on a table, food that has not been eaten

Kinetic Energy: A type of energy that will act upon an object to create work.  There are several types of energy that are all classified as kinetic energy.

• Light Energy
• Light, Sunshine
• Sound Energy
• Sound waves
• Chemical Energy
• Food as our body digests it, a battery
• Mechanical Energy
• Our bodies move while using Mechanical energy, any motion
• Heat Energy (sometimes this is listed separate from Kinetic energy but not everyone agrees with that)
• Toaster as it browns bread, light bulbs (some more than others)

Work & Power

We have been studying work and power.  Work is what happens when energy acts on an object.  For example, a toaster uses electrical energy and converts it to heat energy.  The work done by a toaster is toasting bread.  It is a change in an object due to energy.  The way work is calculated when an object is moving up is by multiplying the mass of an object by the rate of gravity (9.8 meters per second squared) by the height the object is being lifted.  We have used the example of climbing the stairs at Trillium.  The height of the stairs is 4 meters and if a student has a mass of 60 kg, the work could be calculated by
W = 60 x 9.8 x 4.  The unit for energy and work is Joules.

Power is the rate at which work is done.  It can be calculated by dividing Work by time (P=W/t).  This concept is one that is very similar to our concept of power used by most students in every day language.  The more powerful a student was going up the stairs it meant they either moved more mass at the same time or moved the same mass at a faster time.  Power's units are watts.

Energy

We are going to start exploring ENGERY.  Energy is the ability to do work or to make change.  If you think about your body, in order to make your body move, you need energy.  It's not something you can tell when energy is present.  Seeing a light on, feeling the wind blow, feeling heat from a fire and hearing noises are all ways of experiencing energy.

There are two types of energy.  The first is POTENTIAL ENERGY which is a stored energy.  A car that is off but has a full gas tank, snow at the top of a hill, and food all have potential energy.  KINETIC ENERGY is the other type of energy and its the energy possessed by a moving object such as a snowball being thrown, my body while typing this blog post, and a moving car.

A lot of things will have both potential and kinetic energy such as a bouncy ball.  As the ball drops, it has more and more kinetic energy because its velocity (or speed) is increasing as it goes to the floor.  After it hits the floor and bounces back up, the kinetic energy transforms into a potential energy.  The amount of energy in the bouncy ball never changes (unless something else causes it to change like the impact of the ball with the floor) but it can continue to change back and forth between potential and kinetic energy.

Newton's Laws of Motion

Newton's First Law of Motion:
This law talks about INERTIA.  It means that an object that is at rest wants to stay at rest unless a force acts upon the object.  This means that an object will continue to stay still unless something makes it move.  Also, an object in motion wants to stay in motion unless a force changes its motion.  That means that if an object is moving there must be a force such as friction or air resistance to cause that object to stop.  An object already moving must also have a force act upon it in order to change its direction.  If something is traveling straight, it must hit a wall, another object, a bump in the road, or encounter another change in force to make it change its course of motion.

Newton's Second Law of Motion:
This is the law that tells us that F=m*a or Force = Mass times Acceleration.  This means that the force an object has can change depending on the mass of the object and the acceleration of the object.  We experienced this the day we did the three different labs.  One team rolled a car down a ramp into the back of another car and found that the faster the car traveled the further the second car moved.  Another team swung a pendulum into a cardboard object.  When the mass of the pendulum was increased, the distance the cardboard was pushed increased.  The third team used the force plate to determine the amount of force a ball had when dropped from different heights.  The higher the ball started, the more acceleration it had when it hit the force plate and therefore it had more force.

Newton's Third Law of Motion:
This law is the law that says every action has an equal and opposite reaction.  We've talked about this with the Normal Force.  Remember the example of a book sitting on a table?  The normal force is a force that the table pushes onto the book and it is equal and opposite of the force of gravity.  The other example we discussed in class is an astronaut firing a gun in outer space.  The astronaut would fly backwards with the same amount of force as the bullet being propelled from the gun because when a gun is fired, the bullet and the person experience a force that is equal and opposite.  Force diagrams are great ways to show these forces because the vectors indicate the direction of the force and the length of the vector arrow tells us how strong the force is.  When the arrows face opposite directions and are the same length, that shows us on the force diagram that the forces are equal and opposite.

Week of September 27-October 1

It has been amazing getting to know the students in my classes!!  I have throughly enjoyed the students and teaching.  I'm really excited for where we can go in the curriculum throughout the rest of the semester and this week will be no exception!

This week we are going to spend Tuesday as a work week.  There are several assignments we need to finish and we are going to do a review assignment.  The topics we are going to cover will include the metric system and speed.  All students should be able to convert between metric units (ex. how many centimeters are in 562 millimeters?) and calculate speed between two points given the difference in distance and the time it took to travel that distance.

Thursday we will have a quiz.  This will be our first quiz of the year and will cover the two topics mentioned above.  The quiz will be very similar to the review worksheet we will complete.  The main purpose for this quiz is to allow me the opportunity to evaluate each students' progress towards our classroom goals.

After our quiz on Thursday we will work on more experiments so we can gain a better understanding of motion.

Homework due Thursday 9/16

Thanks for such a wonderful first day!!  It was really great getting to meet you all and I promise I will try to do better with your names Thursday!!!!

There are two assignments due Thursday:
1. Parent and student signatures on the safety form
2. Observing Objectives Worksheet should be completed with the Venn diagram on front, data table on back, and the 3 questions.

Make-up Assignment for Absences

Complete one media report for each class that has been missed.  The media report will replace the participation points missed for the day that you were absent from class.

To complete the media report, you must read a newspaper article, magazine article, or journal article or watch a movie or TV show that surrounds a scientific concept.  The source you find must be nonfiction (it is true…or to the best of our knowledge).

Introduction

This blog is for the Middle School Science classes at Trillium.  I will try to keep this current so that all students and parents will be able to use this as a guide to our class.