When you hear the word science, lots of things probably come to your mind. Maybe stuff like this:
78
-
Upload
nickolas-dixon -
Category
Documents
-
view
213 -
download
0
Transcript of When you hear the word science, lots of things probably come to your mind. Maybe stuff like this:
When you hear the word science, lots of things probably come to your mind. Maybe
stuff like this:
We’re interested in knowing what you think. So, tell us:
What is Science?
1
Maybe you wrote,
“Science is learning about plants and animals and rocks and planets”
Or, maybe you wrote,
“Science has a lot of facts and hard vocabulary words”
You might even have written,
“Science is all about boring stuff I don’t care about. I like art and social studies and music a lot
better.”
None of these answers is wrong.
Science involves all of these things.
(Like anything else, science can be boring. Most scientists love their jobs, but even they get bored
sometimes.)
Still, we need a definition of science that we can all share. That way, we know we’re all talking
about the same thing.
The following question might help us make a definition of science.
What can be done during science class that won’t be done during math, language arts, or social
studies? (Give examples)
2
Maybe you wrote that you go outside and watches butterflies getting nectar from flowers.
Maybe you wrote that your class puts baking soda into vinegar and describes what happens.
You might even have written that you use tools such as magnifying glasses to study fossils.
Answers like these help us figure out how science is different than other subjects.
Science makes knowledge that humans use to understand things and events in the natural world.
VOCABULARY
How do people make scientific knowledge?
One way to make scientific knowledge is to observe things and events many times.
What does it take?
Consider the example of the Sun
People have seen the Sun rising and setting for thousands of years.
These repeated observations help us trust our knowledge about what the Sun will do each day.
More recently, scientists have used special telescopes to figure out that the Sun is a star
made mostly of hydrogen and helium.
So, repeated observation of the natural world is one way to make scientific knowledge.
Think ahead to the year 2023.
Predict two things that will happen to broad leaf trees (maples and oaks, for example) as the
seasons change from summer to fall,
And then from fall to winter.
3
Do you think your prediction will come true?
4
Explain your answer
5
VOCABULARY
Fair test is another way to make reliable knowledge by planning and running an
experiment.
Why is it called a “fair” test?
Look at it this way.
Imagine that you’re playing a game, but the rules of the game make it completely impossible for
you to win.
In other words,
The results of the game are known before the game even
starts!
The game is unfair.
How is a fair game different than an unfair game?
6
A fair test is like a fair game.
A fair test has carefully defined rules which do not change during the test.
Changing the rules during the test would be cheating!
Results of a fair test are not known ahead of time.
Scientists who plan and run a fair test may think they know what the results will be
But
It is possible for the actual results to be different from what the scientists expect.
A fair test leaves room for unexpected results.
There’s a lot that goes into planning and running a fair test.
A story has been written to take you through the process of doing both planning and running a fair
test.
John and Brenda are 6th grade students learning about plants.
One day, they become curious about something they’ve noticed:
Plant stems always grow up into the air,
And
Plant roots always grow down into the soil.
But why?
So, John and Brenda ask their teacher this question:
What makes the stems of plants grow up and the roots of plants grow down?
7
At this point, the teacher has 2 choices.
She can give them the answer.
She can help them discover the answer.
When do you remember things better?
When a teacher gives you an answer, or when you discover the answer by yourself?
8
The teacher asks,
“Well, what do you think? What makes stems grow up and roots grow down?”
After thinking for a moment,
Brenda says,
“Light. A little light gets through the soil. So, light is what causes stems to grow up and roots to
grow down.”
Okay, now stop.
Let’s think about this story as a scientist would.
Fair tests usually start with curiosity
(something that grabs your interest and that you want to know more about)
You can then put your curiosity in the form of a question.
A good question helps you figure out exactly what you want to know more about.
Finally,
You can make a statement that is a possible answer to your question.
Notice that we said
“a possible answer”,
Not
“the right answer”
If you already knew the right answer,
You probably wouldn’t be curious about what you saw, right?
VOCABULARY
Your statement just needs to be one that you can support, disprove, or change because of
observation or a fair test.
Scientists call such a testable statement a
hypothesis
What are John and Brenda curious about?
What question helps them figure out what they want to know more about?
9
10
What is their hypothesis, or testable statement?
11
John, Brenda, and their teacher plan and set up a fair test to figure out whether light makes stems
grow up and roots grow down.
They take the following steps.
1. They soak four corn seeds in water overnight. This will help the seeds sprout quickly.
2. They put wet sponges into two glass Petri dishes.
3. They put two corn seeds in each dish, and tape the dishes shut.
4. They balance the dishes on their sides and tape them to the table so they will not fall.
They cover the left dish with a box so no light reaches the seeds.
They shine a light over the other dish.
Everything else about the dishes is exactly the same:
Type of corn in the dishes
Amount of water in the sponges,
And so on.
In 5 days, they’ll lift the box and compare the seeds in the 2 dishes
What do you think will happen to the seeds in the light?
12
John says the stems will grow up to reach the light and the roots will grow down to get away
from the light
Okay, how about the seeds in darkness?
13
John and Brenda talk to each other then decide:
The stems and roots in darkness won’t know which way to grow, so they’ll grow all over the
place.
They’ll be totally confused!
The teacher only said, we’ll see if you are right in 4 days
Let’s stop and think like scientists.
To plan a fair test, you must identify 3 things:
VOCABULARY
Independent variable
This is something that you control or change during your experiment
Dependent variable
What you measure, count, or observe happening due to the change to the independent variable
Constants
All of the other things that should be kept the same throughout the fair test
(everything except your independent variables)
The goal of a fair test is to figure out what effect (if any) the independent variable has on the
dependent variable
By keeping all other conditions constant, your fair test will examine only the relation between the
independent variable and the dependent variable.
What is the independent variable in John and Brenda’s fair test?
14
15
What is the dependent variable in John and Brenda’s fair test?
What are some constants in the fair test?
(name at least 3)
16
As you plan a fair test, you should also make a prediction
about how the dependent variable will react to the independent variable.
In other words, you should predict the results of your fair test.
Remember a hypothesis is your statement that you can support, disprove, or change because of
observation or a fair test.
Your prediction must be based on your hypothesis.
By comparing your prediction with the actual results of the fair test,
You can judge whether your hypothesis was supported, not supported, or somewhere in-
between.
What prediction did John and Brenda make?
17
stems will grow up to reach the light and the roots will grow down to get away from the light
stems and roots in darkness won’t know which way to grow, so they’ll grow all over the place
Scientists often put a hypothesis into an “if-then” statement.
If I change the independent variable then this will happen to the dependent variable
Look at John and Brenda’s hypothesis that they made then write it in an “if-then” sentence.
18
After 5 days, John, Brenda and their teacher lifted the box and compared the seedlings in the
dishes.
This is what they see.
Seedlings Grown in Dark
Seedlings Grown in Light
Based on the photos, was John and Brenda’s hypothesis correct? Explain.
19
The photos show that, in both sets of plants, the stems definitely grew up and the roots mostly
grew down
So, John and Brenda’s hypothesis seems to be at least partially unsupported
It isn’t light that makes plant stems grow up and roots grow down
It’s probably something else
This is their conclusion
VOCABULARY
Restates the hypothesis that the experiment tested and prediction based on the hypothesis
AND
States whether the results indicate that the hypothesis was supported, not supported or
somewhere in-between
A conclusion may also spark a new investigation.
If the results don’t support the hypothesis, then it’s time to make a new hypothesis
and
plan a new test
John and Brenda are still curious about why stems grow up and roots grow down.
Their teacher tells them that gravity causes both things to happen.
Suppose John and Brenda want to plan a fair test to examine their teacher’s claim.
What would be the independent variable in such a test?
20
Why would it be hard for John and Brenda to test their teacher’s claim?
21
Does the fact that their hypothesis was not supported make John and Brenda bad scientists?
No
Absolutely not!
Scientists often prove a first hypothesis wrong
When this happens, a scientist will make a second hypothesis, plan and run a new fair test,
and compare the new results to the second hypothesis
A scientist may do this several times until he or she finds a hypothesis that seems to explain what
he or she is curious about.
A fair test is part of a larger process called a
Scientific investigation
Not all investigations follow these steps, but the following diagram shows the general pattern for
most investigations
1. Observe and generalize
2. Ask a question
3. Form a hypothesis
4. Make a prediction
5. Experiment and observe
3. Change hypothesis
4. Make a prediction
5. Experiment and observe
Repeat steps 3-5 until prediction matches observation, then
6. Report findings
Scientific investigation
The procedures used in science to produce data
There’s one last thing to keep in mind about fair tests:
They can usually be improved!
Maybe the question can be more focused.
When planning a fair test, always think about ways to make it better.
Maybe the hypothesis can be more clearly stated!
Maybe more conditions need to be held constant.
When many tests show that a hypothesis is probably correct,
The hypothesis becomes something stronger than a “possible” answer.
It becomes an explanation
VOCABULARY
Why an object is the way it is
Or
Why an event happens as it does
Some explanations are reasonable,
Which means that they seem possible given our knowledge of nature.
Other explanations are unreasonable
Which means that they do not seem possible given our knowledge of nature
Write a reasonable explanation for why the following events happen.
Flocks of birds fly south during the winter months
On extremely rare occasions, a black disk covers up the Sun during the day.
22
23
Before ending this review, let’s quickly compare the goals of science with the goals of technology
The goal of science is
To study things and events in the natural world and make predictions
The goal of technology is
To improve the world by making things that can solve human problems and improve human lives
Suggest one way in which each of the following objects, designed by people, have either solved a human problem or improved the quality of human
life
Candles: 24
Light bulbs:25
Refrigerators:26
Stoves:27
Benjamin Franklin
(United States 1706 – 1790)
Benjamin Franklin has often been called the
“First American”.
As one of the signers of the Declaration of Independence, Franklin was an important
political figure.
In addition, he was a well-known writer and inventor.
Franklin’s most famous experiment involved him flying a kite into a storm cloud.
The kite drew a spark of electricity from the storm cloud
Because of this, Franklin realized that a bolt of lightning is actually a spark of electricity with an
enormous amount of energy.
Luckily, lightning did not strike the kite directly, or Franklin could easily have died from
electrocution.
Using the knowledge he gained from his discovery about lightning, Franklin invented the
lightning rod, which protects buildings from being damaged by lightning.
His other inventions include:
Bifocal glasses
A furnace stove
The odometer
Just to name a few!
A scientific investigation usually begins with curiosity and a question
Produce a hypothesis and plan a fair test or a set of observations to test it
A fair test studies how an independent variable might affect a dependent variable
A hypothesis can be wrong. Don’t be discouraged if an experiment doesn’t produce the
results that you expected
Technology makes objects that solve problems and improves lives
