Deal or No Deal? When I moved to

Portugal, a friend offered me a Volvo in perfect shape for 112,000,000$ Escudos.

Would you buy it?

Discuss with partner what you would need to know.

Dimensional Analysis

(The Railroad Method)

Today, we will learn how to perform

Dimensional Analysis

(Rail Road Method)

Why do we use this?

1. When we are in Europe and we want to know how many miles is 15 kilometers.

2. To convert metric (SI) units (i.e.- grams) to conventional units (i.e.- ounces).

3. When traveling internationally, being able to convert currencies.

4. To do well in all science courses in high school and college!!

When would we use the Railroad Method??

1. When we are in Europe and we want to know how many miles is 15 kilometers.

2. To convert metric (SI) units (i.e.- grams) to conventional units (i.e.- ounces).

3. When traveling internationally, being able to convert currencies.

4. To do well in all science courses in high school and college!!

Simple Steps for Conquering the Railroad MethodProblem: Convert 15 km to miles.

1. Draw your Railroad.

2. Write what “they” give you in the first line. (i.e.- ‘15 km’)

3. Put the “given UNIT” (km) diagonal.

4. Put the “desired UNIT” (miles) vertically opposite the “given UNIT”.

5. Now, how many _______ are in ________? Here, how many km’s are in miles (or vice versa)? By the way,

1.6 km = 1 mile

6. Cancel out any same diagonal units (here the km’s)

7. Multiply everything on top. Multiply everything on the bottom.

8. Divide. Your answer is in the unit that remains.

Examples

1. How many km’s equal to 5 miles?

2. How many dollars is 33,333 colones? (475 colones= $1)

3. In Physics we use “m/s” for our unit for speed. How many “m/s” is 1 mph (mile per hour)?