M2 Discussion 2 Instructions:  Electricity Simulations and the Cost of Electricity

Part I: Simulations

Overview

The University of Colorado has created many different types of interactive science simulations through their PhET project. These simulations will allow science-based explorations to help understand the concepts in electricity and magnetism.

Instructions for Part I

For this discussion you must go to the University of Colorado’s PhET Interactive Simulations webpage and complete the following:

Choose one simulation from the list of possible simulations under the heading, “Electricity, Magnets, and Circuits.”

Complete the simulation.

Create a post where you describe the simulation and what you learned while completing the simulation.

Relate the simulation to something you read about in Chapters 18 and 20 of the textbook.

Part 2: Calculating Electricity Costs

Overview

Electricity has revolutionized our society in the last two centuries yet it also binds us into a regional community that depends on one electrical grid. What if that grid failed? How dependent are we on electricity? What is the cost of electricity, to both you as the consumer and to society at large?

First of all, sometimes appliances don’t report the watts. Recall that amps x volts = watts. If you have any two of the three quantities, you can complete this math equation. If the appliance you first choose does not report two of the three, choose a different appliance.

Here is an example: In a greenhouse there is one very old infrared quartz heater that is used in the colder seasons to keep the temperature up at night (8 hours of use). It is very energy efficient but very old so they were thinking about replacing it. It uses 1500 watts.

cost = ((1,500W)(8 hrs)($0.046/kWh))/1,000 (W/kW) =$0.55 per day x 30 days = $16.50 mo.

You will be able to see your electrical cost per hour in the account summary of your electrical bill. It doesn’t look like a money number because of all the decimal points, i.e. mine says 716 kWh x 0.046040. The 0.046040 is the cost per kilowatt hour ($0.05). Compare this to a space heater that uses a 120 volts and 45 amps (usually you will find 120 or 240v).

120 volts * 45 amps = 5,400 watts

cost = ((5,400W)(8hrs)($0.046/kWh))/1,000 (W/kW) = $1.99 per day x 30 days = $59.70 mo.

You can easily see the difference between these two heaters!

Instructions for Part II

Choose one appliance from your home and complete the calculations outlined above.

Write at least 50 words (1 paragraph) to summarize your comments:

Name your appliance

Show your mathematical work

Describe your impression…Does the amount used by the appliance surprise you based on your total electricity bill?