Science
Skills
Introduction to the Metric System
Lesson 1.2
Making conversions between metric units
is easy!
Making Metric Conversions
Try some metric conversions on your own!
First practice some conversions here.
You can find some practice problems in your e-journal.
Scientific Method
In the next lesson, we will begin making different measurements
using laboratory tools. Before we do that, lets review the scientific
method. If you recall from 6th grade, the scientific method is a way
of solving problems that can include several different steps. It allows
you to methodically analyze the evidence, come up with an idea about
what is happening, test your idea, gather data, and most importantly,
draw conclusions about whether you are right or wrong.
Remember to click on me!
The scientific method is a guide used to solve problems.
Consider this: you go to the garage to get your bicycle. You notice
that the rear tire is flat. Around the tire you see broken glass.
Then you begin to make some guess as to how the bicycle may be on
flat. When you proceed to actually fix the flat you find a nail embedded
into the inner tube. Were your initial thoughts correct? The way of
thinking about solving a problem is called the scientific method.
The basic steps of the scientific method are:
Identify the Problem - State it clearly- usually
as a question. You must have a problem that needs to be solved. Think
back on the bicycle scenario. What was the problem?
Gather Information- Research; ask questions.
Discover what is already known about the problem. How did you collect
more information about the flat tire? What are some other options
you could have taken to find out more information on how the tire
became flat.
State a Hypothesis- a hypothesis is a suggested
solution as to why something happens. What did you think or guess
about how the bicycle became flat?
Test your hypothesis - experiment to see if your
hypothesis is correct. Be sure to make careful observations, using
all of the information your senses can gather.
Record the data. Keep careful records.
What tools if any did you use to make observations on how the tire
became flat? Did you use just eyes? When you make observations using
the five senses, it is called a direct observation. Can you recall
the five senses? (sight, smell, taste, hearing, and touching.) The
first four are found on your head. Just remember you made observations
directly, without any tools. When you make observations using tools,
this is called indirect observations.
Organize and Analyze the Data- Put the data in
order. Scientists use charts and tables to organize data. Write the
steps of the approach you took in collecting your data.
State a conclusion - explain the data. Sate whether
or not it supports the hypothesis. What was the final answer to the
reason the tire became flat? Was your initial guess or hypothesis
correct? This information is stated in the conclusion. In addition,
you can mention what further experiments could be done to provide
more evidence or support, or what new questions might have been raised
by your experiment and results.
Different problems require different approaches. Not
every step in scientific method needs to be used. And the steps can
be used in any order. However, when reporting the steps in a science
investigation this is the format used:
Problem
The question you are trying to answer
Hypothesis
An educated guess about what you think the solution
is. Usually worded as an "If....then" statement. Ex. "If
the amount of water in the film canister increases, then the reaction
time will be faster"
Materials
The list of all equipment and supplies needed
Procedure
The step-by-step instructions of how to perform the
experiment
Observation
All the results of the experiment, whether they are
what you saw, or data of times or numbers.
Conclusion
What was the result of the experiment. Was your hypothesis
supported or not? What experiments do you think could be done that
would yield further, better results?
Data tables charts and graphs are very important in
reporting information. Most of the time a chart contains words or
descriptions while a table usually contains numbers. You must always
give your chart, table and graph a title according to the information
it is giving.
There are several ways in which to communicate data.
You can use pictures, draw diagrams, take photographs, and show graphs.
The most common types of graphs are the line graph, bar graph, and
pie graph. The line graph shows progression or change over time. Bar
and pie graphs are typically used to compare things. Remember you
must always have a title on any method you choose. Otherwise it will
appear like this one at the right. You know it contains percentages,
but what of?
When creating a graph, you must be able to identify what you have been testing
in the experiment. This means you must be able to distinguish between the
different types of variables. The chart below has the different types.
Type
of Variable
Definition
Example
independent
This is the one variable that you deliberately change.
It is sometimes called the manipulated variable. Experiments
should have only one manipulated variable.
If you wanted to know how fertilizer affects plant
growth, the amount of fertilizer given to each plant is the only
variable that you would change.
dependent
The dependent variable is the variable that is
being observed, which changes in response to the independent variable.
It is sometimes called the responding variable.
In the fertilizer experiment, the responding variable
would be the size of the plants
controlled
Variables that are kept constant are called
controlled variables. These are all the things that are kept the
same in your experiment.
Controlled variables in the fertilizer experiment
would include factors such as the amount of light and water given
to each plant, the type of soil used, the size of the pot, and the
temperature.
Here are some examples:
Experimental
Question
Manipulated
Variable
Responding
Variable
Constant
Does temperature affect how long soap
bubbles last?
temperature
time soap bubbles last
type of soap used
Which color of light causes beans to grow best?
color of light
growth of plants
the amount of light and water given to each plant,
the type of soil used, the size of the pot, and the temperature.
Does the mass of an object affect
the speed with which it falls?
mass
time
distance object falls, type of object
How does the angle of a ramp affect the speed
at which an object will move down it?
angle of ramp
time
length of ramp, type of object
Once you have identified what your manipulated and responding variables
are, you can make a graph.
Line graphs are labeled in a special way. The x-axis
on a graph is where you place the manipulative variable (also called
the independent variable). You will place it on the x-axis along with
the units. For example, in the bubble experiment above, you would
place the temperature along the x-axis, in degrees Celsius.
The responding variable (also called the dependent variable)
goes on the y-axis. You also must include units of the responding
variable. For example, in the soap experiment above, the responding
variable would be length of time the soap bubbles last, in seconds.
Come up with three different experiments that you might
like to do. They need to be different from the ones we have talked
about or seen so far. For each of the three experiments, give your
hypothesis, quickly describe in a sentence or two how you would test
it, and then identify the manipulated variable and the responding
variable.
Do you still have questions about the metric system?
