Lighter-Than-Air Flying Devices - Science 8

Multiple Choice

What is the definition of lighter-than-air flying devices?

• Devices that generate lift using gases lighter than air

• Devices that generate lift using engines

• Devices that generate lift using wings

• Devices that generate lift using propellers.

Multiple Choice

Which of the following is an example of a lighter-than-air flying device?

• Helicopter

• Airplane

• Airship (like blimps)

• Jet

Multiple Choice

Lighter-than-air flying devices achieve lift due to ______.

• Gravity

• Buoyancy

• Thrust

• Drag

Multiple Choice

What is the density of air?

• 1.114 kg/m³

• 1.225 kg/m³

• 1.300 kg/m³

• 1.000 kg/m³

Multiple Choice

Helium is used in balloons because it is ______ than air.

• heavier

• lighter

• the same weight

Multiple Choice

Why is helium considered more affordable compared to other gases?

• It is more abundant

• It is lighter

• It is cheaper to produce

• It is safer.

Multiple Choice

What are the large holding tanks in airships filled with helium called?

• Balloons

• Ballonets

• Tanks

• Chambers

Multiple Choice

Helium makes the airship ______ buoyant, causing it to rise.

• Negatively

• Positively

• Neutrally

• Not

Multiple Choice

How is the altitude of an airship controlled?

• By adjusting helium and air levels in ballonets

• By changing the shape of the airship

• By increasing speed

• By using external weights

Multiple Choice

What action causes an airship to rise?

• Adding more helium

• Pumping air into ballonets

• Releasing helium

• Adding weight

Multiple Choice

To make an airship descend, you should pump air into ______.

• helium tanks

• ballonets

• the cabin

• the engine

Multiple Choice

What keeps an airship at a steady altitude?

• Increasing helium

• Balancing helium and air

• Reducing weight

• Pumping air into ballonets

Multiple Choice

What causes a hot air balloon to rise?

• Cold air inside the balloon

• Heated air inside the balloon

• The weight of the balloon

• The color of the balloon.

Multiple Choice

Fill in the blank: Heated air molecules move faster and spread out, reducing ____.

• A) Temperature

• B) Density

• C) Pressure

• D) Volume

Multiple Choice

Why is the air inside a hot air balloon less dense than the outside air?

• Because it is colder

• Because it is heated

• Because it is compressed

• Because it is humid.

Multiple Choice

What happens to the air inside a hot air balloon when it is heated with a torch?

• It becomes more dense

• It becomes less dense

• It remains the same

• It becomes solid.

Multiple Choice

To make a hot air balloon go down, you should stop the heat, allowing the air to cool and the balloon to descend due to ____.

• Wind

• Gravity

• Pressure

• Temperature

Multiple Choice

Which of the following actions will cause a hot air balloon to ascend?

• Cooling the air inside the balloon

• Heating the air inside the balloon

• Releasing air from the balloon

• Adding more weight to the balloon.

Multiple Choice

Which gas is used by airships to achieve lift?

• Oxygen

• Helium

• Nitrogen

• Carbon Dioxide

Multiple Choice

Hot air balloons achieve lift by using ______.

• Helium

• Heated air

• Cold air

• Hydrogen

Multiple Choice

Both airships and hot air balloons depend on having a lower ______ inside the balloon than outside.

• Pressure

• Temperature

• Density

• Volume

Multiple Choice

What is buoyancy?

• The ability of an object to float in a fluid

• The ability of an object to sink in a fluid

• The ability of an object to dissolve in a fluid

• The ability of an object to evaporate in a fluid.

Multiple Choice

Helium and hot air are used as lighter-than-air gases because they are ______.

• more dense than air

• less dense than air

• the same density as air

Multiple Choice

How is the control of altitude achieved?

• By adjusting the amount or temperature of the gas

• By changing the color of the gas

• By adding more weight to the object

• By reducing the size of the object.