Boyle’s Law and Charles’ Law

Volume: What’s the Matter?

Solids and liquids have a definite volume . The container of a liquid or a solid may change, but the volume will remain the same . For example, 50 ml of water will stay 50 ml of water no matter what size the container. Likewise, if you put a Jolly Rancher in a huge container, it will still stay the same size (even though we might wish for it to get bigger!) Volume is the amount of space something takes up.(size)

Gases behave differently . Think of a balloon. What happens when it pops? Where does the air go? Think about when you put • • more air into a tire. What

Think – Pair – Share

happens to the spacing of

What is the shape of a gas?

the particles that were

What is the volume of

inside the tire already?

a gas?

Name 3 unique •

Can the volume of a

•

gas change? Can the spacing

characteristics of gases. (think – pair – share)

between the particles of a gas change?

Unique Characteristics of Gases

•Gases take the shape of their containers (think balloon and tire) In other words, they do not have a definite shape.

•

Gases do not have definite volumes. They fill their containers (think of the balloon popping in a room)

•The amount of empty space can change in a gas (Think of filling a beach ball or tire)

Pressure is the amount of force exerted on a given area. A beach ball has fewer particles of gas colliding inside of it than a basketball. Fewer collisions mean less force. Less force=less pressure.

How can you prove this?

How Gases Behave Under Pressure

video

Imagine a diver at a depth of 10 meters blowing a bubble of air. As the bubble rises, its volume increases. By the time the bubble reaches the surface, its original volume will have doubled as a result of the decrease in pressure. (What happens to water pressure at the top of the water?) Why do balloonists have to be careful about how much helium they use to fill their balloon?(What happens to the atmospheric pressure the higher you go in the atmosphere?)

Robert Boyle

The Honorable Robert Boyle (January 25, 1627 December 30, 1691) was an Irish natural philosopher , chemist, physicist, and inventor, noted for his work in physics and chemistry. He is largely regarded today as the first modern chemist.

Boyle’s Law

As the P As the P This law states that for a fixed amount of gas at a constant temperature, the volume of a gas increases as its pressure decreases . Likewise, the volume of the gas decreases as its pressure increases .

the V the V

The V as the P

Boyle’s Law

The V as the P What do the V and P stand for in this diagram? Explain

How Gases React as the Temperature Changes

Video

Jacques Charles

Jacques Charles was an 18 th Century (born in the 1700’s) French inventor, scientist, mathematician and balloonist. He made the first flight in a hydrogen balloon on August 27, 1783.

Charles’s Law

Charles’ Law states that for a fixed amount of gas at a constant pressure, the volume of the gas increases as its temperature increases . Likewise, the volume of the gas decreases as its temperature decreases .

Explain what would happen to this balloon if taken outside on a cold winter day

Graphing Charles’ Law

Charles’ Law

The V as the T The V as the T What do the V and the T stand for in this diagram? Explain

Charles’s Law and Bicycle Tires Exit Ticket

One of your friends over inflated the tires on her bicycle. Use Charles’s Law to explain why she should let out some of the air before going for a ride on a hot day.