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Session 7. Heat and Temperature
Weather balloon. |
Learning Goals
During this session you will have an opportunity to build
understandings of the following concepts:
- Heat is the transfer of energy between two
objects with different temperatures.
- Temperature is a measure of the average energy
of motion of particles.
- Heat is added when solids change state into
liquids and when liquids change state into gases (e.g., in melting, evaporation,
and boiling).
- Heat is removed when gases change state into liquids and when
liquids change state into solids (e.g., in condensation and freezing).
Video Overview
What makes the liquid in a thermometer rise or fall in response
to temperature? Which contains more heat—a boiling teakettle or a swimming
pool of lukewarm water? In this session, we focus on the difference between
heat and temperature and examine how both are defined in terms of particles.
We also use the particle model to explain a number of everyday phenomena,
from why things expand when they are heated to the role that temperature plays
in changes of state.
Video Outline
This session opens by examining the everyday but amazing
phenomenon of ice and why it feels colder to us than ice water. We then
go to the Science Studio where we ask a fifth grader Joana what a thermometer will
read after it has been “bundled up” in a blanket for half
an hour. Another fifth grader Lydia explains her ideas about whether or
not heat is matter.
Science historian Al Martinez takes us to the Saugus Iron
Works in Massachusetts and recounts some of the history of the scientific
understanding of heat
through the processes of combustion and friction. We then take a closer
look at heat
transfer between different forms of matter on a particle
level.
Back in the Science Studio, Lydia compares how different
wood and aluminum blocks feel to the touch. But what is she measuring—heat
or temperature? Then Joana takes the temperature of ice water just after
the ice is removed
and later on, discovers that not all liquids have the same boiling
point.
Continuing in the Science Studio, third grader Sara observes
a classic demonstration of the effect of heat on the volume of a solid.
But what
about liquids? At the Roosevelt School in Worcester, Massachusetts,
science coordinator Paula
Proctor leads her sixth graders through
an investigation
of the effect of heat and cold on the volume of a red liquid in a
thermometer. If the liquid goes up, is its mass changing? The same experiment
is
then repeated in the Science Studio, where Lydia weighs the thermometer
liquid
before and after heating, and David, a fifth grader, conducts an
experiment to determine the effect of heat on the density of air.
The session
ends with a “bang” when lead forecaster Bill Babcock
of the U.S. Weather Service explains how thunderstorms get started
when warm, less-dense air next to the ground rises, taking water vapor
with
it. View the video ==>
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