Measurement Physical Science

Tools and Measurement

by Mrs. Ojerio

Poll

How much do you think this hippopotamus weighs?

• 7000 pounds

• 31,138 newtons

• 3.5 short tons

​International System of Units

• ​They are all correct! They are the same amount, just in different units.

​International System of Units

​Americans are more familiar with units such as pounds, feet, miles, and gallons.

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​Scientists use International System of Units, or SI.

• ​Length: Meters (m)

• ​Mass: Gram (g)

• ​Volume: Liter (L)

Match

Match each SI Unit with the correct measurement.

• Meter (m)

• Gram (g)

• Liter (L)

Length

Mass

Volume

• Length

• Mass

• Volume

​SI Units: ​SI Units are based on multiples of 10.

​A horse eats 7,000 g of grass a day. How many kilograms is that? Decigrams? Centigrams? Milligrams?

​Combining Measurements

​Combining Measurements

​Combining Measurements

Multiple Choice

What is the area of a rug with length = 2.50 m and width = 1.50 m?

• $$3.75\ m^2$$  

• $$3.75\ m$$  

• $$4\ m^2$$  

• $$4\ m$$  

​Combining Measurements

• ​Weight: an object's mass x force of gravity acting on the object

• ​Mass is not the same thing as weight!

• ​Mass is constant no matter where you are.

• ​Weight is depending on location.

  • ​EX) Dedra's weight is highest on the Sun because Gravity is the largest.

Multiple Choice

How do you think Dedra's mass would change if she were to travel to the Moon?

• Her mass would decrease

• Her mass would increase

• Her mass would stay the same

​Temperature Scales

Multiple Choice

The formula for converting kelvins (K) to degrees Celsius $$\left(C\degree\right)$$  is:

$$\degree C\ =\ K\ -273$$  

Using this formula, convert 400 K to degrees Celsius.

• $$673\degree C$$  

• $$127\degree C$$  

• $$-673\degree C$$  

• $$-127\degree C$$  

​Quantitative Measurement Tools

• ​Some tools are used to make measurements.

• ​When you take measurements, you are working with numbers (or quantities).

• ​These are called quantitative observations.

​Qualitative Measurement Tools:

• ​Some tools are used to make observations about an object's shape, color, smell, or texture.

• ​These are describing an object's qualitities.

• ​These are called qualitative observations.

Multiple Choice

Which tool would you use to measure the mass of an object?

Multiple Choice

Which tool would you use to measure the volume of an object?

​Precision and Accuracy

• ​Measurements should be both precise and accurate.

• ​Precision: how close measurements are to one another.

• ​Accuracy: how close a measurement is to the true value.

​Scientific Notation: helps scientists write very large or very small numbers.

The mass of the moon is very large (73,480,000,000,000,000,000,000 kg). Write this number in scientific notation:

STEP 1: Write the number without the place-holding zeros: 7348

STEP 2: ​Move the decimal point to between the first and second digits: 7.348

​STEP 3: Count the number of places that you moved the decimal point:

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​STEP 4: Write the number in scientific notation:

The size of a bacteria is very small (0.0000000567 m). Write this number in scientific notation:

STEP 1: Write the number without the place-holding zeros: 567

STEP 2: ​Move the decimal point to between the first and second digits: 5.67

​STEP 3: Count the number of places that you moved the decimal point:

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​STEP 4: Write the number in scientific notation:

Multiple Choice

Write 24,500 in scientific notation:

• $$2.45\ x\ 10^4$$  

• $$2.45\ x\ 10^{-4}$$