The rising of warm air creates a phenomenon known as an (a)   .

Clouds are formed from millions of tiny water (a)   .

When the ice crystals in a cloud grow heavy enough, they fall as (a)   .

Wind is caused by the movement of air due to differences in (a)   .

An engine requires three key ingredients to run: gas, air, and a (a)   .

The movement of fuel from the tank to the engine is done through a (a)   .

The process of mixing air and fuel in the engine takes place in the (a)   .

A spark plug generates the (a)   necessary to ignite the fuel mixture.

The function of the exhaust system is to remove burnt (a)   from the engine.

Airplanes rely on (a)   moving across their wings to create lift.

When the nose of a plane tips up too far, it slows down and enters a state called a (a)   .

A (a)   provides the forward motion needed to keep air moving over the wings of a plane.

The up-and-down movements of a bird's wings provide both lift and (a)   .

Flaps on an airplane's wings are used to help it (a)   by changing the flow of air.

The Ferris wheel in the episode required (a)   energy to power its motion.

When the cable broke, the class had to find alternative sources of (a)   .

The rocks falling into one set of seats used the energy of (a)   to turn the Ferris wheel.

To move the rocks up the mountain, the class built a (a)   powered by the wind.

The paddle wheel worked using the kinetic energy of (a)   .

By concentrating sunlight, the team was able to generate (a)   to power their rock launcher.

The combination of wind, water, and solar power ultimately helped the class complete their (a)   project.

Miss Frizzle and the class were on their way to the (a)   Museum for a rehearsal.

Carlos struggled to make his (a)   instrument sound right for the concert.

The house they discovered turned out to be the (a)   Museum.

Professor Contralto was described as a collector of (a)   .

Carlos learned that all sounds are made by something (a)   .

High sounds are made by something vibrating (a)   , while low sounds are made by something vibrating slowly.

Carlos discovered that the key to making a perfect sound was removing the extra (a)   from his instrument.

The asteroid tracked by Dorothy Ann is coming from the direction of (a)   .

Miss Frizzle and her class decided to reflect sunlight onto the comet using the (a)   .

Dorothy Ann calculated the asteroid's path by plotting points from her (a)   .

The class avoided crashing into the moon by performing an (a)   burn.

To alter the asteroid's path, the class used the (a)   of the space bus to create gravitational pull.

When the asteroid couldn't be melted, they decided to send it on a path toward the (a)   .

The asteroid's collision with Earth was prevented by using the (a)   on the space pod.

Miss Frizzle described the asteroid's orbit around the bus as an (a)   orbit.

Objects sink when their (a)   is greater than the water they displace.

The bus managed to sink to the bottom of the lake by adding extra (a)   to its structure.

A (a)   pushes up on an object submerged in water, counteracting its weight.

(a)   objects sink more easily because they displace less water.

To make the bus rise back to the surface, the class pumped (a)   into the pontoons, replacing the water.

Submarines use (a)   tanks to switch between floating and sinking.

The (a)   of water is responsible for pushing objects upwards when they float.

A bread ball sinks because it is (a)   than a bread slice, even though they weigh the same.

The shape and size of an object affect its (a)   in water.

Increasing the bus’s (a)   caused it to float again.

Light travels in (a)   lines away from the source that produces it.

When light hits a mirror, it (a)   and changes direction.

Shadows are created when an object blocks (a)   from reaching a surface.

A (a)   light is used in theaters to keep light on even when the main lights are off.

Objects become visible when light (a)   off them into our eyes.

A shiny, curved surface like a mirror can (a)   light to direct it into a specific area.

Light can be reflected off a transparent surface like (a)   to create illusions.

Light moves so fast that it seems (a)   to the human eye.

A (a)   can aim light into dark areas to make them visible.

The 'Pepper's Ghost' trick uses (a)   and reflections to create a ghostly image.

Stars are formed in regions called (a)   , where dust and gas combine under gravity.

The sun is classified as a (a)   star, in the middle of its life cycle.

A red supergiant star is (a)   than the sun but has a shorter lifespan.

When a red supergiant dies, it may explode in a (a)   .

The process of nuclear (a)   provides the energy that makes stars shine.

A star 'born' when (a)   hydrogen atoms into helium starts in its core.

The color of a star indicates its (a)   , with blue stars being hotter.

A (a)   is a system of stars, gas, and dust bound by gravity.

A star's brightness as seen from Earth is called its (a)   magnitude.

A computer requires (a)   to tell it what to do and how to perform tasks.