Evaluating a Mechanical Device

Mechanical devices have evolved over time due to advancements in science and technology

Look at the progression of the lawn mower

Was made of steel and moved by a person pushing it

The First Lawn mower

Moved onto using gasoline and electricity to make it much lighter and easier to use

Now we have moved onto more advanced forms such as ride on movers and even robotic mowers

In order for us to improve the machines we have today we constantly evaluate them

Companies use these evaluations to make their products better, different from other brands so people will buy them

Even you evaluate devices before you buy one

Evaluations

BlackBerry IPhone

WHICH WOULD YOU RATHER HAVE

In order for evaluations of a device to work there must be areas or criteria that we are looking at

These criteria are the areas of interest that we will be focusing on in order to decide which product to buy

Criteria to Evaluate a Device

Criteria;◦ What are we using our bike for?

Street riding? Trails Riding? BMX riding? Competition racing?

◦ Each of these features is part of your criteria for evaluating your new bike Each will lead you towards a different option…which

is right for you◦ Another important part to criteria is the COST

EX. BUYING A NEW BIKE

In previous notes we talked about how you can calculate efficiency by going MA/SR.

Efficiency can also be described in words by comparing how well or fast you can accomplish a task

A machine is efficient if it does its job well

Efficiency Vs Effectiveness

Effectiveness is related to how useful the machine is in the specific situation

The best machines combine high efficiency and high effectiveness

Using the lawn mowers as an example;◦ The push mower and the ride-in mower both are

effective at mowing the lawn but the ride in is far more efficient at it

◦ You cover the same distance but you do so quicker and by expelling less energy

Efficiency Vs Effectiveness cont….

Function is what the device is suppose to do

The design is the physical form of the device that makes it usable

Looking at racing bikes we can see how different designs affect how the function of it

Function and Design

Mountain Bike 21-speed Race Bike

Danny MacAskill – 5mins http://www.youtube.com/watch?v=iRN84UW

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Going Outside a Function

◦ You have just received your license and as deal with your parents they have agreed to give you $30,000 towards a car.

◦ However, they will not just buy you any new vehicle, they want to make sure you do your homework before you go off and decide on any vehicle

◦ Your job is to create a realistic criteria that you will be looking at before you even start shopping around for your perfect vehicle. You will be comparing 3 different models of vehicle and

comparing each of their criteria's to the one you made.

You will write a paragraph using your criteria on why the car you choose is the most appropriate

Evaluating a Device

You have $10,000 in your bank to put towards your car .

You will not be able to afford a new car with the money your parents give to you so you will have to make a choice;

1. Buy a car that totals $40,000 2. Buy a car that’s less then $40,000 and

keep the rest. You must buy a car worth at least $20,000