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science often starts when we observe
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something and it makes us wonder
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one way to explore the questions we have
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is to use the scientific method
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the scientific method creates a
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framework for logically and
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systematically experimenting in order to
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find answers
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it has several steps including forming a
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question
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researching background information
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making a hypothesis
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doing an experiment
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analyzing data and communicating the
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results
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in this video we will look at each step
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of the scientific method in more detail
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using the science of popping boba
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juice-filled balls that pop in your
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mouth
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as an example formulating the question
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we want to answer is the first step of
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the scientific method
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a scientific question usually starts
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with who
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what
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when
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where
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why or how the most important thing
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about your question is that it must be
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testable
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this means it needs to be something that
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you can do an experiment to figure out
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so while you might be tempted to ask a
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general question like how is popping
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boba made this isn't a good scientific
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question to answer that question
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all you need is a recipe
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instead choose a more specific question
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like what kinds of liquids can be turned
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into popping boba or
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what determines the size and shape of
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popping boba with these more specific
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questions we could experiment by testing
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different liquids or by changing the
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process by which we make popping boba
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sometimes you can wonder about something
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but not know enough about the topic to
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make a question that is specific and
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testable
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that's okay
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if that happens you can start with a
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general question go on to step two and
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then come back and refine your question
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to make it testable once you know more
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about the topic
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step two is doing background research
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in this step we want to find out as much
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as possible about our research topic and
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learn from the experiences of others
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when doing background research we can
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find information in many different
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places
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we can use books in the library search
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the internet or ask an expert or
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specialist questions about the subject
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we are exploring
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learning more about the subject helps us
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to find the best way to do things gives
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us clues about what data we need to
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collect or explains how to set up our
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experiment
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in our popping boba example we could
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research different popping boba recipes
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to find out what ingredients are
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necessary to turn juice into juice balls
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we might also want to find out what the
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purpose of each ingredient is
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what equipment is used
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and what factors affect the ability of a
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liquid to successfully become hopping
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boba
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all this information will be helpful for
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the next steps of the scientific method
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with the information we have gathered we
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can move on to step number three which
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is constructing a hypothesis
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a hypothesis is an educated guess based
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on background research about the answer
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to our question a hypothesis always
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includes a prediction that is easy to
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test and measure
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it's common for the prediction to take
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the form of if i do this then
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this will happen
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for example based on the background
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research we did for our popping boba
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project we learned that sodium alginate
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a key ingredient in some popping boba
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recipes only thickens in environments
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that are not too acidic
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thinking about how this might affect our
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popping boba we might come up with a
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hypothesis that says
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if i use liquids that are very acidic
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then the popping boba shape will be less
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spherical
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once we have made our hypothesis we will
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test it by designing and carrying out an
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experiment
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to do this we first need to identify the
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variables of the experiment there are
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usually three different kinds of
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variables the independent variable is
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the one and only variable that is
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changed during the experiment
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in our popping boba experiment the
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acidity or ph of a liquid would be a
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good independent variable that we could
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change to investigate how acidity
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affects the shape of the popping boba
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the dependent variable is the one that
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is measured during the experiment to
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determine the effects of the changes we
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are making
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in our popping boba experiment we want
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to know if the shape of the popping boba
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changes
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since good popping boba is considered to
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be spherical or ball like in shape we
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could measure the longest and shortest
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dimension or the diameter and height of
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the popping boba we make it is okay to
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have more than one dependent variable
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controlled variables are all the other
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conditions in the experiment that we
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want to keep the same
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in our popping boba experiment the
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reaction temperature or quantities of
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each ingredient are some examples of
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controlled variables by keeping all the
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controlled variables the same we know
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that any changes in the height or
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diameter of the boba are due to the
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acidity of our juice instead of one of
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these factors
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determining the variables of our
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experiment helps us to come up with an
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experimental procedure or step-by-step
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instructions that will allow us to
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collect the data we need to test our
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hypothesis
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a simplified experimental procedure for
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our popping boba experiment could look
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like this
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choose a liquid or food you want to test
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then follow a step-by-step recipe to
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make several popping boba balls
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measure the diameter and the height of
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each ball using graph paper
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and finally redo the experiment but
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change the acidity of the food mixture
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an important aspect of a scientific
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experiment is to repeat the experiment
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for each testing condition several times
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to make sure that the results are
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reproducible and not random
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make sure to carefully record everything
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you do
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measure and observe in a lab notebook so
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that you have a clear record of your
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experiment
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taking videos pictures or making
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drawings is also a good idea
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when doing our experiment we need to
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actively ask is the procedure working as
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we collect our data if the experiment is
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not working we will need to troubleshoot
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the procedure and restart the experiment
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for example we might find that it is
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really difficult to produce a single
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drop of food mixture using a syringe
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this means that we have to rethink our
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procedure and then redo the experiment
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for example instead of using a syringe
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we might try using a medical dropper
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the goal of conducting the experiment is
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to collect enough data to confidently
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determine if our hypothesis is supported
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or not
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the next step after we finish our
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procedure and have collected our data is
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to review and analyze our data analyzing
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the data means looking at it in as many
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ways as we can
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this includes things like calculating an
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average for the different trials of our
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experiment
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making graphs and evaluating whether or
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not the collected data is complete of
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good enough quality and is valid
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for our popping boba experiment we could
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make graphs that show how the diameter
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or height of our popping boba balls
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change with juice acidity
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in graphs like these we usually place
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the independent variable on the x-axis
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and the dependent variable on the y-axis
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it is important to label your graphs and
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results clearly and include their
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measurement units
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if our data is sufficient we can then
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draw conclusions about whether or not
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our data supports our hypothesis it is
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okay if our hypothesis is not supported
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this happens often to scientists
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sometimes the data leads to more
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questions and the process starts again
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with a slightly different question and a
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new hypothesis
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the final step of the scientific method
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is communicating our results
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this means communicating all of our data
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and findings in a written report
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oral presentation or in some other way
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so that anybody who is interested in
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making popping boba balls can use our
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information to optimize their size shape
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and deliciousness
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now that you know how the scientific
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method works
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you are ready for your next science
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adventure
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remember though that questions in some
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areas of science can be more easily
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tested than others
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don't be afraid to modify steps of the
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scientific method for example if direct
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experimentation is not possible to test
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your hypothesis you could use a
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simulation or mathematical model instead
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just keep in mind that the goal of your
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investigation should be to discover
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cause and effect relationships by asking
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questions
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carefully gathering and examining the
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evidence
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and seeing if all the available
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information can be combined into a
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logical answer
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if you want to practice the scientific
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method or need more information
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visit us at www.sciencebuddies.org
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where you can find thousands of free
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hands-on science and engineering
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projects
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you