Before the Bell Rings

• Collect all handouts.

• DO NOT TRY TO SOLVE ANY PROBLEMS!!!!

• Have out bellwork sheet. Be ready to begin when the bell rings.

• Honors: Get a text book.

Bellwork

• Today, scientists must search through scientific journals before performing an experiment or making methodical observations. Where would this step take place in a diagram of scientific methods? Why?

• Answer in complete sentences!!

Factor Label Method

• Please copy down the notes I tell you to copy down. :)

• Thanks!

Conversion factorsConversion factorsConversion factors for 1 ft = 12 in

foot 1

inches 12 or

inches 12

foot 1

There are almost an infinite number of conversion factors that include meters:

mm 1000

m 1 ,

cm 100

m 1 ,

km 1

m 1000

m 1

yards 0.9144 ,

inches 39.37

m 1 ,

feet 3.28

m 1

The steps to followThe steps to followNow we are ready to solve problems using the

factor label method. The steps involved are:

1. Write down the desired quantity/units

2. Equate the desired quantity to given quantity

3. Determine what conversion factors you can use (both universal and question specific)

4. Multiply given quantity by the appropriate conversion factors to eliminate units you don’t want and leave units you do want

5. Complete the math

Factor label exampleFactor label exampleQ - How many kilometers are in 47 miles?

(note: 1 km = 0.621 miles)

First write down the desired quantity

# km

Q - How many kilometers are in 47 miles? (note: 1 km = 0.621 miles)

Next, equate desired quantity to the given quantity

# km = 47 mi

Factor label exampleFactor label example

Q - How many kilometers are in 47 miles? (note: 1 km = 0.621 miles)

Now we have to choose a

conversion factor

# km = 47 mi

Factor label exampleFactor label example

Q - How many kilometers are in 47 miles? (note: 1 km = 0.621 miles)

What conversion factors are possible?

# km = 47 mi 1 km 0.621 mi

0.621 mi 1 km

Factor label exampleFactor label example

Q - How many kilometers are in 47 miles? (note: 1 km = 0.621 miles)

Pick the one that will allow you to cancel

out miles

# km = 47 mi 1 km 0.621 mi

0.621 mi 1 km

Factor label exampleFactor label example

Pick the one that will allow you to cancel

out miles

Q - How many kilometers are in 47 miles? (note: 1 km = 0.621 miles)

# km = 47 mi 1 km 0.621 mi

0.621 mi 1 km

Factor label exampleFactor label example

Q - How many kilometers are in 47 miles? (note: 1 km = 0.621 miles)

Multiply given quantity by chosen conversion factor

# km = 47 mi 1 km 0.621 mi

0.621 mi 1 km

Factor label exampleFactor label example

Q - How many kilometers are in 47 miles? (note: 1 km = 0.621 miles)

Multiply given quantity by chosen conversion factor

# km = 47 mi x 1 km 0.621 mi

Factor label exampleFactor label example

Q - How many kilometers are in 47 miles? (note: 1 km = 0.621 miles)

Cross out common factors

# km = 47 mi x 1 km 0.621 mi

Factor label exampleFactor label example

Q - How many kilometers are in 47 miles? (note: 1 km = 0.621 miles)

Cross out common factors

# km = 47 x 1 km 0.621

Factor label exampleFactor label example

Q - How many kilometers are in 47 miles? (note: 1 km = 0.621 miles)

Are the units now correct?

# km = 47 x 1 km 0.621

Factor label exampleFactor label example

Q - How many kilometers are in 47 miles? (note: 1 km = 0.621 miles)

Yes. Both sides have km as units.

# km = 47 x 1 km 0.621

Factor label exampleFactor label example

Q - How many kilometers are in 47 miles? (note: 1 km = 0.621 miles)

Yes. Both sides have km as units.

= 47 x 1 km 0.621

# km

Factor label exampleFactor label example

Q - How many kilometers are in 47 miles? (note: 1 km = 0.621 miles)

Now finish the math.

# km = 47 x 1 km 0.621

= 75.7 km

Factor label exampleFactor label example

Q - How many kilometers are in 47 miles? (note: 1 km = 0.621 miles)

The final answer is 75.7 km

# km = 47 x 1 km 0.621

= 75.7 km

Factor label exampleFactor label example