Physical Properties | Open Textbooks

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What is Matter?

Matter is anything that has mass and takes up space. Everything around you is made of matter - your desk, the air you breathe, water, even you! Scientists describe matter using its physical properties - characteristics that can be observed and measured without changing what the substance is.

Key Physical Properties

⚖️ Mass

The amount of matter in an object. Mass is measured in grams (g) or kilograms (kg).

Example: A bowling ball has more mass than a basketball because it contains more matter.

📦 Volume

The amount of space an object takes up. Volume is measured in liters (L), milliliters (mL), or cubic centimeters (cm³).

Example: A beach ball has more volume than a golf ball, even though the golf ball has more mass.

🎯 Density

How much mass is packed into a given volume. Density = Mass ÷ Volume. Objects with greater density sink in water.

Example: A rock sinks in water because it's denser than water. A cork floats because it's less dense.

🌡️ Boiling/Melting Point

The temperature at which a substance changes state. Each substance has its own specific melting and boiling points.

Example: Water melts at 0°C and boils at 100°C. Gold melts at 1,064°C!

🎨 Color

A property you can observe with your eyes. Color helps identify substances.

Example: Copper is reddish-brown, gold is yellow, and silver is gray-white.

💪 Hardness

How resistant a substance is to being scratched. Harder substances can scratch softer ones.

Example: Diamond is the hardest natural substance. It can scratch glass, but glass cannot scratch diamond.

States of Matter

Matter exists in three main states: solid, liquid, and gas. Each state has different properties based on how the particles are arranged and move.

Solid

🧊

Particles packed tightly together
Definite shape
Definite volume
Particles vibrate in place

Liquid

💧

Particles close but can slide past
No definite shape (takes container shape)
Definite volume
Particles flow freely

Gas

💨

Particles spread far apart
No definite shape
No definite volume (expands to fill space)
Particles move very fast

Remember: Physical properties can be observed without changing what the substance IS. If you measure the mass of ice and then melt it, it's still water - just in a different state!

Examples

Property Identification Challenge

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Practice

Test your knowledge of physical properties.

Question 1: Which of the following is NOT a physical property?

A) Color

B) Mass

C) Flammability (ability to burn)

D) Boiling point

Question 2: A wooden block floats in water. What does this tell you about the wood?

A) Wood has more mass than water

B) Wood is less dense than water

C) Wood has more volume than water

D) Wood is harder than water

Question 3: Which state of matter has a definite volume but takes the shape of its container?

A) Solid

B) Liquid

C) Gas

D) All of the above

Question 4: An object has a mass of 20 grams and a volume of 10 cm³. What is its density?

A) 2 g/cm³

B) 200 g/cm³

C) 0.5 g/cm³

D) 30 g/cm³

Check Your Understanding

Key Questions to Consider

What physical properties could you use to tell the difference between salt and sugar?
If an object sinks in water, what does that tell you about its density?
How do the particles in a solid behave differently from particles in a gas?
Why can't you use color alone to identify a substance?

Think About It: Scientists often need to use multiple physical properties to identify a substance. Water and rubbing alcohol are both clear liquids, but they have different boiling points, densities, and smells!

Summary

⚖️

Mass

Amount of matter in an object

📦

Volume

Amount of space taken up

🎯

Density

Mass divided by volume

🔄

Three States

Solid, liquid, and gas

Next Steps

Practice measuring mass and volume of objects at home
Observe different states of matter in your daily life
Move on to learn about chemical changes