1. Lesson 3: Mass

2. English vs. Metric Units
1 pound = grams
Which is larger?
1. 1 Pound or 100 Grams
2. 1 Kilogram or 1 Pound
3. 1 Ounce or 1000 Milligrams
1 kilogram = 2.2 pounds
1 ounce of gold = 28,349.5 milligrams

3. Kilogram Prototype Image - http://en.wikipedia.org/wiki/Kilogram
Metric Units kg g cg mg
Mass refers to the amount of matter in an object.
The base unit of mass in the metric system is the gram and is represented by g.
Standard: 1 gram is equal to the mass of one cubic centimeter of water.
(Start at 1:42)
Metric Units
1 Kilogram (km) = 1000 Grams (g)
1 Gram (g) = 1000 Milligrams (mg)
Which is larger?
A. 1 kilogram or 1500 grams
B milligrams or 1 gram
C. 12 milligrams or 12 kilograms
D. 4 kilograms or 4500 grams
Kilogram Prototype Image -

4. _______ + _______ + _______ = ________ g
Measuring Mass
We will be using triple-beam balances to find the mass of various objects.
The objects are placed on the scale and then you move the weights on the beams until you get the lines on the right-side of the scale to match up.
Once you have balanced the scale, you add up the amounts on each beam to find the total mass.
What would be the mass of the object measured in the picture?
_______ + _______ + _______ = ________ g
Top Image: Bottom Image:

5. Measuring Mass – Triple-Beam Balance
1st – Slide the weights to the left (zero) and place the object on the scale.
2nd – Slide the large weight to the right until the arm drops below the line. Move it back one groove. Make sure it “locks” into place.
3rd – Repeat this process with the medium weight. When the arm moves below the line, back it up one groove.
4th – Slide the small weight on the front beam until the lines match up.
5th – Add the amounts on each beam to find the total mass to the nearest tenth of a gram.

6. Mass & Inertia Mass is a measure of inertia, or resistance to motion.
An object with a large mass will be harder to get to move than an object with smaller mass because the object with large mass has greater inertia.
Imagine trying to kick a bowling ball like a soccer ball…
less mass = less inertia more mass = more inertia

8. Step 1: Step 2: Step 3: If you finish early:
Guess your item(s) for each targeted mass.
Step 2:
Bring your papers to Mrs. Johnson before you get your scales.
Step 3:
Measure the actual mass of the items you guessed for each targeted mass.
If you finish early:
Mass Challenge:
Use a graduated cylinder and balance to find the mass of 100 milliliters of water. Explain and illustrate the procedure that you used.

9. Clean Up
Put all ITEMS back in the ZIPLOC You should have 8 items plus your magazine (not including any small paperclips that fell out)
Return ITEMS and SCALES to your LAB STATION.
Keep your PAPER in your FOLDER and PACK UP your folders.
Return to your seats. We will do a Jolly Rancher Review if we have time! 