Compare Object Sizes - Middle School Earth and Space Science
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What solar-system measurement is the distance across an object through its center?
What solar-system measurement is the distance across an object through its center?
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Diameter. Measures straight through the center from edge to edge.
Diameter. Measures straight through the center from edge to edge.
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Which is larger: a planet’s radius of $7{,}000\text{ km}$ or its diameter?
Which is larger: a planet’s radius of $7{,}000\text{ km}$ or its diameter?
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Diameter. Diameter is always twice the radius.
Diameter. Diameter is always twice the radius.
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Which unit is most appropriate for planet diameters in data tables: km, m, or mm?
Which unit is most appropriate for planet diameters in data tables: km, m, or mm?
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km. Planets are thousands of kilometers wide.
km. Planets are thousands of kilometers wide.
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What is the formula for the diameter-to-radius relationship?
What is the formula for the diameter-to-radius relationship?
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$d=2r$. Diameter is twice the radius.
$d=2r$. Diameter is twice the radius.
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What does density mean in planetary data tables?
What does density mean in planetary data tables?
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Mass per unit volume. Calculated as $\rho = \frac{m}{V}$.
Mass per unit volume. Calculated as $\rho = \frac{m}{V}$.
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What does mass measure when comparing solar-system objects?
What does mass measure when comparing solar-system objects?
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The amount of matter in an object. Different from weight, which depends on gravity.
The amount of matter in an object. Different from weight, which depends on gravity.
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What does volume measure when comparing sizes of solar-system objects?
What does volume measure when comparing sizes of solar-system objects?
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The amount of space an object occupies. Measured in cubic units like km³.
The amount of space an object occupies. Measured in cubic units like km³.
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What does radius mean when comparing sizes of planets or moons?
What does radius mean when comparing sizes of planets or moons?
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Radius is half of an object’s diameter. The radius extends from center to edge.
Radius is half of an object’s diameter. The radius extends from center to edge.
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What does it mean if two objects have equal diameter but different mass in a data table?
What does it mean if two objects have equal diameter but different mass in a data table?
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They have different densities. Density varies with composition and structure.
They have different densities. Density varies with composition and structure.
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Identify the larger value: diameter $12{,}742\text{ km}$ or radius $6{,}371\text{ km}$.
Identify the larger value: diameter $12{,}742\text{ km}$ or radius $6{,}371\text{ km}$.
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Diameter $12{,}742\text{ km}$. Diameter is exactly twice the radius value.
Diameter $12{,}742\text{ km}$. Diameter is exactly twice the radius value.
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Which graph type best shows how a single object’s measured diameter changes over time?
Which graph type best shows how a single object’s measured diameter changes over time?
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Line graph. Shows continuous change over time.
Line graph. Shows continuous change over time.
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Which graph type best compares diameters of several planets in one view?
Which graph type best compares diameters of several planets in one view?
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Bar graph. Shows discrete values for easy comparison.
Bar graph. Shows discrete values for easy comparison.
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If object A has $2$ times the radius of object B, how many times larger is A’s volume (same shape)?
If object A has $2$ times the radius of object B, how many times larger is A’s volume (same shape)?
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$8$ times. Volume scales with radius cubed: $2^3 = 8$.
$8$ times. Volume scales with radius cubed: $2^3 = 8$.
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If one planet’s diameter is $2$ times another’s, how many times larger is its volume (same shape)?
If one planet’s diameter is $2$ times another’s, how many times larger is its volume (same shape)?
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$8$ times. Volume scales with diameter cubed: $2^3 = 8$.
$8$ times. Volume scales with diameter cubed: $2^3 = 8$.
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Which is larger: object A radius $2{,}000\text{ km}$ or object B diameter $3{,}900\text{ km}$?
Which is larger: object A radius $2{,}000\text{ km}$ or object B diameter $3{,}900\text{ km}$?
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Object A (diameter would be $4{,}000\text{ km}$). A's diameter is $4{,}000\text{ km}$, larger than B's $3{,}900\text{ km}$.
Object A (diameter would be $4{,}000\text{ km}$). A's diameter is $4{,}000\text{ km}$, larger than B's $3{,}900\text{ km}$.
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Which object is larger if A has diameter $50{,}000\text{ km}$ and B has $5.0\times10^4\text{ km}$?
Which object is larger if A has diameter $50{,}000\text{ km}$ and B has $5.0\times10^4\text{ km}$?
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They are the same size. Scientific notation: $5.0\times10^4 = 50{,}000$.
They are the same size. Scientific notation: $5.0\times10^4 = 50{,}000$.
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Which is larger: $1.2\times10^5\text{ km}$ or $98{,}000\text{ km}$?
Which is larger: $1.2\times10^5\text{ km}$ or $98{,}000\text{ km}$?
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$1.2\times10^5\text{ km}$. $1.2\times10^5 = 120{,}000$, which exceeds $98{,}000$.
$1.2\times10^5\text{ km}$. $1.2\times10^5 = 120{,}000$, which exceeds $98{,}000$.
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What is the radius if a moon’s diameter is $3{,}474\text{ km}$?
What is the radius if a moon’s diameter is $3{,}474\text{ km}$?
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$1{,}737\text{ km}$. Divide diameter by 2: $3{,}474 \div 2 = 1{,}737$.
$1{,}737\text{ km}$. Divide diameter by 2: $3{,}474 \div 2 = 1{,}737$.
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Which is larger: $3.6\times10^3\text{ km}$ or $3{,}500\text{ km}$?
Which is larger: $3.6\times10^3\text{ km}$ or $3{,}500\text{ km}$?
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$3.6\times10^3\text{ km}$. $3.6\times10^3 = 3{,}600$, which exceeds $3{,}500$.
$3.6\times10^3\text{ km}$. $3.6\times10^3 = 3{,}600$, which exceeds $3{,}500$.
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What is the diameter if a planet’s radius is $24{,}622\text{ km}$?
What is the diameter if a planet’s radius is $24{,}622\text{ km}$?
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$49{,}244\text{ km}$. Multiply radius by 2: $24{,}622 \times 2 = 49{,}244$.
$49{,}244\text{ km}$. Multiply radius by 2: $24{,}622 \times 2 = 49{,}244$.
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What measurement is most appropriate for comparing the sizes of moons when data are given in kilometers?
What measurement is most appropriate for comparing the sizes of moons when data are given in kilometers?
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Diameter in kilometers. Consistent units allow direct numerical comparison.
Diameter in kilometers. Consistent units allow direct numerical comparison.
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What measurement is most appropriate for comparing the sizes of planets in a data table?
What measurement is most appropriate for comparing the sizes of planets in a data table?
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Diameter (or radius) of each planet. Diameter directly measures size across the widest point.
Diameter (or radius) of each planet. Diameter directly measures size across the widest point.
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What is the relationship between diameter and radius of a spherical object?
What is the relationship between diameter and radius of a spherical object?
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$d = 2r$. Diameter is twice the radius for any sphere.
$d = 2r$. Diameter is twice the radius for any sphere.
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Identify the correct ratio of diameters: A $= 10{,}000\ \text{km}$ and B $= 5{,}000\ \text{km}$; what is $\frac{d_A}{d_B}$?
Identify the correct ratio of diameters: A $= 10{,}000\ \text{km}$ and B $= 5{,}000\ \text{km}$; what is $\frac{d_A}{d_B}$?
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$2$. $\frac{10{,}000}{5{,}000} = 2$.
$2$. $\frac{10{,}000}{5{,}000} = 2$.
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Find the correct comparison: Object A radius $= 1{,}000\ \text{km}$, Object B radius $= 2{,}000\ \text{km}$; which has greater volume?
Find the correct comparison: Object A radius $= 1{,}000\ \text{km}$, Object B radius $= 2{,}000\ \text{km}$; which has greater volume?
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Object B. B has $2\times$ radius, so $8\times$ volume.
Object B. B has $2\times$ radius, so $8\times$ volume.
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