Video Transcript
The diagram shows how the first
part of the solar system formed. A cloud of gas and dust in
space. The cloud of gas and dust begins to
contract due to gravity. As the cloud of dust and gas
contracts, it blank and starts emitting light. Which words would replace the
blanks? (A) Heats up, (B) cools down.
So in this question, we’re thinking
about the formation of the solar system, which started out as a cloud of gas and
dust in space. The word we use to describe this
cloud is a nebula. Over time, this nebula begins to
contract due to gravity. As the cloud contracts, the
particles of gas and dust move faster and faster, and they collide more often with
each other. These collisions cause the
temperature and pressure of the cloud to increase. And at the same time, they generate
heat and light.
The cloud becomes most dense and
hot in its center or core, which is where the Sun will eventually form. We can say that the gravitational
potential energy of the nebula gets converted into thermal energy and kinetic
energy. And so we know that as the cloud
contracts due to gravity, it’s going to heat up and start emitting light. So the answer to this question is
(A), heats up. And the full final sentence in this
question then reads, “As the cloud of gas and dust contracts, it heats up and starts
emitting light.”
