Question: Why are hotter things less dense?
by Sofia’s group
After you read this, take the quizlet at:
http://quizlet.com/29986334/heat-density-test-flash-cards/
Definition of Density:
The degree of compactness of a substance.
Definition of Heat:
A form of energy associated with the motion of atoms or molecules
Definition of Kinetic Energy:
Energy that a particle or object possesses by virtue of being in motion.
Script:
Kyoka: Hello, today we are here to talk about why hotter things are less dense.
When things, matter are heated, the matter become less dense. But, why does it
happen?
Sofia: Hot things expand because the particles - atoms and molecules - in a heated
substance move faster than the particles around them.
Shahad: They therefore expand, becoming as a group, less dense, especially gas and
liquids. Meaning warmer materials takes up more space but weighs the same in total.
Sofia: If you have hot material and cool material taking up the exact same amount of
space, the hot material will weigh less because there are fewer particles. This is density:
the degree of compactness in a substance.
Kyoka: Conclusion - Hotter things are less dense because when matter is heated, it
expands. This is because the kinetic energy in a heated substance increases. In other
words, the particles in the substance move faster than the particles around them.
Kinetic energy is the energy of being in motion.
Kyoka: To review the explanations: heated things expand because the particles in them
move faster and farther apart. Volume therefore increases and density goes down.
Sofia: To recap the examples, if you have hot material and cool material taking up the
exact same amount of space, the hot material will weigh less. If you have any questions
on the material you have seen today, email us at our UNIS gmail accounts.
Shahad: To study and take the test, visit our Quizlet
Sofia: By clicking the link that we emailed you all titled Why are Hotter Less Dense!
Give them about 5-10 mins. or the option of doing it at home.
Kyoka: We will now check the final scores and see how you all did!
Sofia, Kyoka, Shahad: Thank you for watching!!!