Measurements and Density

Open Ended

Why is it important to use proper units and significant figures when making measurements in science?

Multiple Choice

Which of the following examples best illustrates how data should be reported?

• A runner completes a race in 10.00.

• A bottle contains 2 liters of water.

• A person weighs 150.

• A distance is measured as 5.

Open Ended

Why is it important to include both a number and a unit when recording a measurement?

Multiple Select

Which of the following are base units in the metric system?

• Meter

• Gram

• Liter

• Pound

Multiple Choice

Which of the following is the correct conversion for 1 kilometer?

• 1 kilometer = 1,000 meters

• 1 kilometer = 0.01 meters

• 1 kilometer = 0.001 meters

• 1 kilometer = 100 meters

Open Ended

Explain the difference between mass and weight, and provide an example of each.

Open Ended

How do you determine the number of significant figures in a measured value?

Multiple Choice

According to the rules for significant figures, when does a zero count as a significant figure?

• When it is between two nonzero digits or at the end of a number with a decimal place

• When it is at the beginning of a number

• When it is at the end of a number without a decimal place

• When it is the only digit in the number

Multiple Choice

Which of the following numbers has 3 significant figures?

• 0.00245 mg

• 1.008 mL

• 3.7500 cm

• 29.05 g

Open Ended

Explain how you determine the number of significant figures in the result of a multiplication or division operation using the rules provided.

Multiple Select

Which of the following statements about significant figures in addition and subtraction are correct?

• The answer has the same number of decimal places as the original number with the fewest decimal places.

• The answer has the same number of significant figures as the number with the most decimal places.

• The answer must be rounded to the same number of decimal places as the number with the fewest decimal places.

• The answer must be rounded to the same number of significant figures as the number with the fewest significant figures.

Multiple Choice

In scientific notation, what must the coefficient (y) always be?

• A number between 1 and 10

• Any positive number

• Any negative number

• A whole number

Multiple Choice

What is the correct scientific notation for the number 0.036?

• 3.6 x 10^1

• 3.6 x 10^2

• 3.6 x 10^-2

• 3.6 x 10^3

Density is a measure of mass per unit volume.

- The density of an object is found by taking the mass of the object and dividing it by the volume of the object.

- Because density is derived by using 2 measurements and not one, density is called a "derived value" (not a directly measured value)

​

- if the mass goes up and the volume stays the same the density goes up

- if the mass goes down and the volume stays the same then the density goes down

-if the volume goes up and the mass stays the same the density goes down.

Density Conceptually

Drag and Drop

Both of the blocks have the ​

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. The block on the right has ​

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and therefore a ​

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than the block on the left. The block on the right has a​

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and therefore, the block on the right has a ​ ​

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Drag these tiles and drop them in the correct blank above

same volume

more green particles

greater mass

greater mass per unit volume

lower mass per unit volume

higher  density

Drag and Drop

If I were to add more particles to the cube on the left then the ​

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and if I were to remove particles from the cube on the right then the ​

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. If I were to decrease the volume of the cube on the left then density would​

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and if I were to increase the volume of the cube on the right then the density would ​

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.

Drag these tiles and drop them in the correct blank above

density would decrease

density would increase

increase

decrease

The units of density often depend on the state of matter under consideration.



The units are typically as follows:

​

Units for Density

​Gas = g/L
Liquid = g/mL
Solid = g/cm³

Match

Match the following substances with the most appropriate unit for density:

• solid copper

• liquid water

• oxygen gas

g/cm³

g/mL

g/L

• g/cm³

• g/mL

• g/L

Less dense objects will float and more dense objects will sink (this is basically Archimedes Principle)

​

​Why does an object float?

Drag and Drop

We know that object on the ​ right is ​

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than the liquid because it ​

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and the object on the left is ​

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than the object because if ​

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.

Drag these tiles and drop them in the correct blank above

more dense

sinks

less dense

floats

​You can use the density formula to solve for density, mass, or volume.

Multiple Choice

Rank the objects from MOST dense to LEAST dense.

• left, center, right

• right, center, left

• left, right, center

• right, left, center

• center, left, right

Multiple Choice

Put the liquids in order from most dense to least dense?

• 4, 3, 2, 1
• 1, 2, 3, 4
• 3, 4, 2, 1, 
• 4, 3, 1, 2

Multiple Choice

Jack has a rock. The rock has a mass of 14g and a volume of 2cm³. What is the density of the rock?

• 7 mL
• 7 g/cm³
• 28 g/cm³
• 1/7 g/cm³

Multiple Choice

Frank has an eraser. It has a mass of 4.0g, and a volume of 2.00cm³. What is its density?

• 8.0 g/cm³

• 2.0 g/cm³

• 2 g/cm³

• 8.00 g/cm³

Multiple Choice

Why do objects sink or float in H₂O?

• Because their densities are higher or lower than compared to water

• Because their densities are using gravity to pull down

• Because their densities are heavier or lighter

• Because their mass and volumes are equal

Open Ended

Reflecting on today's lesson about measurements and density, what is one question you still have or one concept you would like to explore further?