Scientific Measurement

The Metric System“Justin” and Elmo

https://www.youtube.com/watch?v=MMsQYjYlBEo

Measurement

• What could you use to measure the length of the classroom if you did not have a ruler or tape?

• Super fab lab! Measuring something big! https://www.youtube.com/watch?v=3hlkRcTmFxY

The Metric System

• The standard system of measurement used by scientists around the world is the SI or the International System of Units.

• The United States does not use this system while almost every other county does.

Why so sad?

• Because it is so easy to use! Based on multiples of 10.

• Each unit is 10 times larger than the next smallest unit and one tenth the size of the next largest unit.

• So you just multiply or divide by 10 to move units.

Measuring Length

• Base unit of measure for length or distance between two points is the meter (m).

• Long distances are measured in kilometers (km). An example: distance between two cities

• Small lengths are measured in centimeters (cm) or millimeters (mm)

• Tool: metric ruler or meter stick

Measuring Length

Ruler: http://www.k12math.com/math-concepts/measurement/ruler-cm.jpg

How many millimeters are in 1 centimeter?

What is the length of the line in centimeters? _______cm

What is the length of the line in millimeters? _______mm

What is the length of the line to the nearest centimeter? ________cm

HINT: Round to the nearest centimeter – no decimals.

1 centimeter = 10 millimeters

Measuring Liquid Volume

• Base unit to measure the volume of a liquid, or the amount of space it takes up, is the liter (L).

• Smaller volumes are measured in milliliters (mL).

• Tool: graduated cylinder

• Read the level at the bottom of

the curve or meniscus.

Measuring Volume

Top Image: http://www.tea.state.tx.us/student.assessment/resources/online/2006/grade8/science/images/20graphicaa.gifBottom Image: http://morrisonlabs.com/meniscus.htm

We will be using graduated cylinders to find the volume of liquids and other objects.

Read the measurement based on the bottom of the meniscus or curve. When using a real cylinder, make sure you are eye-level with the level of the water.

What is the volume of water in the cylinder? _____mL

What causes the meniscus?

A concave meniscus occurs when the molecules of the liquid attract those of the container. The glass attracts the water on the sides.

Measuring Liquid Volume

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Measuring Solid Volume

10 cm

9 cm

8 cm

We can measure the volume of a regular object using the formula length x width x height.

_____ X _____ X _____ = _____

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Amount of H2O with object = ______

About of H2O without object = ______

Difference = Volume = ______

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Amount of H2O with object = ______

About of H2O without object = ______

Difference = Volume = ______

What is the volume of the hammer?

69mL- 65mL = 4mL or 4cm³

What is the volume of the dinosaur?

5.6mL- 4.8mL = 0.8mL or 0.8cm³

Measuring Mass

• Base unit to measure mass (the amount of matter in an object) is the gram (g).

• One gram is approximately the mass of a paper clip.

• Larger masses are measured in kilograms (kg).

• Tool: triple beam balance

Measuring Mass

Top Image: http://www.southwestscales.com/Ohaus_Triple_Beam_750-SO.jpgBottom Image: http://www.regentsprep.org/Regents/biology/units/laboratory/graphics/triplebeambalance.jpg

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

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

What is the mass? 100g + 60g + 3.7g = 163.7g

What is the mass?

500g + 40g +5.2g = 545.2g

Measuring Temperature

• To measure the temperature of a substance, you will use the Celsius scale.

• Temperature is measured in degrees Celsius (C°).

• Water freezes at O degrees Celsius and boils at 100 degrees Celsius.

• Tool: thermometer

What is the temperature?

0°C

-20°C

30°C