Transcript Science in our World

7th and 8th Grade Science
Weiner High School
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Science is the knowledge obtained by
observing natural events and
conditions in order to discover facts
and formulate laws or principles that
can be verified or tested.
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Hypothesis an explanation that is based on
prior scientific research or observations and
that can be tested.
Controlled experiment an experiment that tests
only one factor at a time by using a comparison
of a control group with an experimental group.
Variable a factor that changes in an experiment
in order to test a hypothesis.
A model is a pattern, plan, representation,
or description designed to show the
structure or workings of an object,
system, or concept.
We will discuss 3 types of models:
1.
Physical Models
2.
Mathematical Models
3.
Conceptual Models
1.
Physical Model : A model volcano and a
miniature steam engine are examples of
physical models. Some physical models,
such as a model of a cell, look like the
thing that they model. But a limitation of
the model of a cell is that the model is not
alive and doesn’t act exactly like a cell.
2.
Mathematical Model: A mathematical
model may be made up of numbers,
equations, & other forms of data. Some
mathematical models are simple & can be
used easily. A Punnett square is an
example of a mathematical model.
3.
Conceptual Model: Some conceptual
models are systems of ideas. Others
compare unfamiliar ideas.
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The idea that the solar system formed
from a spinning disk of gas is a
conceptual idea.
Scientist also use conceptual models to
classify behaviors of animals for
example.
A tool is anything that helps you do a task.
 Tools for measuring: One way to collect
data is to take measurements. To get the
best measurements, you need the proper
tools. Stopwatches, metersticks, balances,
thermometers, spring scales, and
graduated cylinders are all tools that
scientists use to take measurements
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Tools for analyzing: Perhaps you need to
find the average of your data. Calculators
are handy tools to help you do
calculations quickly. Or you might show
your data in a graph or a figure. A
computer with the correct software can
help you make neat, colorful figures. Of
course, even a pencil and graph paper are
tools that you can use to graph your data.
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Units of measurement: Making reliable
and accurate measurements is vitally
important to science. In England at one
time the standard for an inch was three
grains of barley placed end to end. Other
standards have been used in the past such
as parts of the body. The foot was used for
measurement but wasn’t really a reliable
source for measurement, due to the
differences in foot sizes.
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In the late 1700’s the French Academy of
Sciences began to form a global
measurement system known as the
International System of Units, or SI. Today,
most scientist and almost all countries use
this system. The greatest advantage to
using this system is that scientist around
the world can compare their observations
and results.
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Meter The basic unit of length in the SI
Area A measure of the size of a surface or a
region.
Mass A measure of the amount of matter in an
object.
Volume A measure of the size of a body or
region in three dimensional space.
Temperature The measure of how hot or cold
something is.
Density The ratio of the mass of a substance
to the volume of the substance.