scientific method 7 th grade. vocabulary control hypothesis law scientific method theory ...
TRANSCRIPT
Use Your Noodle!
Write the following in your Science Notebook.
Analyze:
Your portable CD player stops working. How do you try to fix it?
You have 3 Minutes!
Critical Thinking
Critical thinking is when you use skills to solve problems.
Separating important information from information that is not important is a skill. Identifying the
problem is also another skill.
Solving Problems
Scientists use critical-thinking skills to try to solve problems and answer questions.
Solving problems requires organization. Scientific Method
This is the steps scientists use to solve a problem.
Solving a problem scientifically.
State the problem
Gather Information
Form a hypothesis
Perform an experiment
Analyze data
Draw conclusions
Hypothesis not
supported
Hypothesis supported
Revise Hypothe
sisRepeat many times
How are scientific problems stated?
1st step in solving a problem scientifically is to state the problem.
A vet noticed that 2 cats that are being boarded were scratching and had patches of skin with red sores.
They both were fine when they first arrived. The technician identified this as a problem.
Now she must decide how to gather information about the problem.
How would you solve this problem?
How is scientific information gathered?
Scientists collect information through laboratory observations and experiments.
Information can be collected from fieldwork done outside the laboratory How would you find out how
a bird builds a nest?
Back to the cat problem…..
The vet gathers information by watching the cats closely. She watches to see if the behavior of the cats with the
sores is different than the behavior of the other 2 cats. She observes that other than the scratching, the
behavior of the four cats is the same. The vet finds out that the brand of cat food used at the
clinic is the same as the one the cats get at home. She decides that the two cats are reacting to something
in their environment. She notices that they seem to scratch most after using
their litter boxes
How do scientists form a hypothesis?
After a scientist collect the information, they form a hypothesis. A hypothesis is a
prediction that can be tested.
After collecting the information, the vet hypothesizes that something in the cat litter is irritating the cats’ skin.
Use Your Noodle!
Write the following in your Science Notebook.
Define:
What is a hypothesis? Give two examples.
You have 3 Minutes!
How do scientists test a hypothesis? Scientists test a hypothesis by
performing an experiment. In an experiment, they hypothesis is tested
using controlled conditions.
Back to the cat problem…….
Cat Problem
The vet gets permission from the owner to test her hypothesis by running an experiment.
The vet reads the label on 2 brands of cat litter.
She finds that the ingredients of each brand are the same except that one has a deodorant.
The cat litter in the clinic has a deodorant.
The vet finds out that the litter the cats have at home does not have a deodorant.
How do scientists use control in an experiment?
The vet separates the cats with sores from the other 2 cats.
She puts each of the cats with sores in a cage by itself.
One cat is called the experimental cat. This cat gets a litter box with litter that does
not have deodorant The other cat gets a litter box that has cat
litter with deodorant. The cat with the deodorant cat litter is the
control
Control and variable
A control is the standard to which the outcome of a test is compared. The control cat will be compared with the
experimental cat at the end of the experiment.
Whether or not the cat litter has deodorant is the variable A variable is something in an experiment that
can change. An experiment should have only one variable Other than the difference in the cat litter, the vet
treats the cats the same.
Use Your Noodle!
Write the following in your Science Notebook.
Analyze:
Why is it important to have only one variable in an experiment?
You have 3 Minutes!
How do scientists analyze data?Observation
During the week, the vet observes both cats.
She collects data on how often and when the cats scratch or chew.
She records the data in a journal The data show that the control cat
scratches more often than the experimental one does.
The sores on the experimental cat begin to heal.
The sores on the control cat do not.
How do scientists draw conclusions?
The vet draws the conclusion that the deodorant in the cat litter probably irritated the skin of the two cats.
To draw a conclusion is to get a logical answer to a question based on data and observation. The next step is to accept or reject the
hypothesis. The vet accepts the hypothesis
If she had rejected it, then she world need to conduct new experiments.
Conclusion
The vet realizes that even though she accepted the hypothesis, she should continue her experiment to be surer of her results.
She should switch the cats to see if she gets the same results again. However, if she did this, the healed cat might
get new sores. She makes an ethical decision and stops the
experiment. Ethical decisions are important in deciding
what experiments should be done.
Use Your Noodle!
Write the following in your Science Notebook.
Draw Conclusions:
If the hypothesis is rejected, the scientist has failed. Is this statement true or false?
Explain your reasoning.
You have 3 Minutes!
What do scientists do with results of experiments?
It is important to share the information when using scientific methods.
The vet shares her results with the cat’s owner
She tells him she has stopped using the cat litter with the deodorant.
One of the most important parts of the scientific method is communicating the results!
Developing Theories
After scientists report the results of an experiment that supports the hypothesis, many repeat the experiment.
If the results always support the hypothesis The hypothesis can be called a theory.
Scientific Theory is an explanation of things or events based on scientific knowledge that is the result of many observations and experiments.
Theory Vs. Hypothesis
Hypothesis An educated guess Can be tested Can be observed
Theory Explains many hypotheses Can raise new questions Data or info from new experiments might
change conclusions and theories can change
What is scientific law?
Scientific law is a statement about how things work in nature that seem to be true all the time.
Although laws can be modified as more information becomes known, they are less likely to change than theories.
Use Your Noodle!
Write the following in your Science Notebook.
Explain:
Talk to your neighbor….
Give an example of a scientific law that has changed due to new information.You have 3 Minutes!
Laws
Laws tell you what will happen under certain conditions but do not necessarily explain why it happened.
For example: You might learn about the law of heredity. These laws explain how genes are
inherited, but do not explain how genes work.
How do scientific methods help answer questions?
You can use scientific methods to answer all kinds of questions.
Using these methods does not guarantee that you will get an answer.
Often they lead to more questions and more experiments.
Science is about looking for the best answers to your questions.
Use Your Noodle!
Write the following in your Science Notebook.
Explain:
What scientific laws can tell you about nature.
You have 3 Minutes!