Observation is using all five senses to gain information
about your surroundings
1.
2.
3.
4.
5.
Touch
Taste
Smell
Hear
See
There are 2 kinds of observations:
Qualitative observation describe things and are NOT used for
scientific research.
Quantitative observations are precise measurements that scientists
can use when doing research. (number & unit)
Scientists around the world use a quantitative system of
measurement called the international system (SI) or the
metric system. Scientists can communicate information to
anyone in the world using this system.
•Measurements are described in numbers and units.
•The SI system is based on multiples of ten.
TO MEASURE :
Length
UNIT/SYMBOL:
TOOLS to USE:
rulers
meters/m
Mass
grams/g
triple beam balance
Time
seconds/s
clock, watch, timer
Temperature
degrees Celsius/ C
thermometer
Volume
liter/L
cubic centimeters/ cm3
graduated cylinder
measure with ruler
Inference- to draw a conclusion based on the facts learned
from an observation.
Scientists make observations and develop a problem or question.
Then, scientists design experiments to gain information about the
problem or question.
A scientists must begin an experiment with a plan. First, the scientist must make decisions
about VARIABLES.
3 Kinds of Variables :
1) Independent Variable (Manipulated Variable)- the variable that the
scientist purposely changes (ONLY ONE of these)
2) Dependent Variable (Responding Variable)- the variable that
responds in an experiment; the scientist can’t control this variable
(what the scientist measures)
3) Constants (controlled variables)- factors that must be the same in
both groups
The scientist must identify the control group and the
experimental groups for the experiment.
Control Group•group in the experiment where everything is natural or
unchanged as possible
•There will be only ONE of these (or there may be no control
group at all.)
Experimental Group•Group in the experiment that has a single factor changed
•There can be more than one of these groups
Title:
How do preservatives affect how fast apple slices turn brown?
Leticia timed how fast apple slices turned brown after being dipped in
different preservatives, such as lemon juice, fruit freshener, and lime soda.
Use the information to identify the following:
• Independent variable
• Dependent variable
• Constants
•
•
Control Group
Experimental Groups
1)
2)
3)
Answer:
I.V.- type of preservatives
D.V. -time it takes for the apple to get brown
Constants- type of apple, way the apple is cut, amount of preservatives, dipping time
Control Group- apples NOT dipped in any preservatives
Experimental Groups1) Apple in lemon juice
2) Apple in fruit freshener
3) Apple in lime soda
Before the scientists actually does an experiment, he/she must write a hypothesis.
Hypothesis- a statement about the predicted relationship
between the independent variable and the dependent
variable.
Rules for writing a hypothesis1) It must be in an “If…,then…” format
2) Do not use personal pronouns, like I, me, he, she, we, us, them…
Use this formula when writing a hypothesis-just fill in the red and blue blanks!
If the (I.V.) (increases or decreases), then the (D.V.) will (increase
or decrease).
EXAMPLE:
I.V. – amount of fertilizer
D.V. plant growth
If the amount of fertilizer increases, then the plant growth will increase.
Repeated Trials are done to make sure that the
results of an experiment are as accurate as possible.
Doing many trials ensures that the results are NOT
because of an error or mistake.
HOMEWORK: Fill out another experimental design diagram using the following experiment:
Title:
How does the length of the paper helicopter blade affect
the rotational speed of the blades?
A title is written as a question.
HOMEWORK: Fill out another experimental design diagram using the following experiment:
Write the title on your blank experimental design diagram.
Title:
How does the height of a container’s sides affect the
time for liquid to evaporate?
Title: How does the height of a container’s sides affect the time it takes the liquid to evaporate?
Hypothesis: If the height of a container’s sides increases, then the time it takes for the liquid to
evaporate will increase.
Independent Variable: height of the container’s sides (cm)
Level of I.V.
Level of I.V.
1 cm sides
5 cm sides
Repeated trials
5
Repeated trials
5
Level of I.V.
10 cm sides
Repeated trials
5
Dependent Variable: time for liquid to evaporate (hours)
Constants: type of container; type of liquid; amount of liquid; temperature of the heat
source; location of the containers; starting time
HOMEWORK: Fill out another experimental design diagram using the following experiment:
Write the title on your blank experimental design diagram.
Title:
How does the height of a ramp affect the distance a toy
car will move?
Title: How does the height of the ramp affect the distance a toy car can move?
Hypothesis: If the height of the ramp increases, then the distance a toy car can move will
increase.
Independent Variable: height of the ramp (cm)
Level of I.V.
Level of I.V.
1 cm ramp
5 cm ramp
Repeated trials
15
Repeated trials
15
Dependent Variable: distance the toy car can move (cm)
Constants: same type of ramp; same car; same location
Level of I.V.
10 cm ramp
Repeated trials
15
Classwork- Video on scientific method
Answer on separate paper.
DATE
1- List the 8 steps of the scientific method.
2-Define hypothesis
3- List 3 reasons that it is important to write down your procedures before an experiment.
4- Which group has NO variable being tested?
control group OR experimental group
5- Which group has ONE variable being tested at a a time?
control group OR experimental group
6- What 3 ways can you organize information for your summary?
7- What do you do in the conclusion?
•Organizing data from experiments into data tables helps scientists better understand their
results.
•A scientist must design a data table to use during the course of the experiment to record
measurements of the DEPENDENT VARIABLE.
•There is usually an area on the data table to record the average of the repeated trials. The
average is calculated after ALL data has been gathered and recorded.
•The data will be used to make a graph to illustrate the findings of the experiment.
There are 3 kinds of graphs:
1. Circle graph
2- Bar graph
3. Line graph
CIRCLE GRAPH
•A divided circle
•It shows how a part relates to a whole
•The numbers are written as percents
•The total of the numbers will be 100%
Bar Graphs
•Has bars to help compare things
•Drawn on graph paper
•Vertical line (up & down) is the Y- axis
•Horizontal line (across) is the X-axis
•Choose the scale by looking at the highest and lowest number in your data
•The number divisions on the scale must be equal
•ALL bar graphs have a scale and equal divisions
Line Graphs:
•Lets you plot several forms of data
•Shows changes
•Help to answer an “If…,then..” question (hypothesis)
•X-axis is the INDEPENDENT VARIABLE
•Y-axis is the DEPENDENT VARIABLE
Y-axis
Dependent
Variable
0
Independent Variable
X-axis
When a scientists finishes an experiment, he/she must communicate the
results in a lab report.
Rules for a Lab Report:
•Use proper spelling, grammar, and punctuation
•Write in complete sentences
•Do NOT use personal pronouns (I, we, he, she, us, you, them, ect.)
•Do NOT lie or make up data
•A stranger should be able to repeat the experiment exactly by reading the report.
Parts of a Lab Report:
Title:
Hypothesis:
Materials:
Procedures:
Data/Observations:
Discussion:
Parts of a Lab Report:
Title:
Hypothesis:
** Copy both of these from the experimental design diagram you completed during the
planning of the experiment
Parts of a Lab Report:
Materials: (You must list every single thing that you used) JUST LIST-NO SENTENCES
Materials: 15 small styrofoam cups
plain potting soil
250 ml measuring cup
water
Parts of a Lab Report:
Procedures: (You must list in detail every step you did when setting up this experiment)
***Someone should be able to repeat the experiment exactly by reading your directions
Procedures: Get 15 small styrofoam cups. Label each cup with a number 1-5 for the control
group and the 2 experimental groups. Organize all of the cups in the tray. Put 10 scoops of
plain potting soil in all of the cups. Put one lima been seed 5 cm into the soil and cover the
seed with soil.
Parts of a Lab Report:
Data/Observations: (look at the measurements and notes in your lab log for important
information about the results of the experiment)
Data/Observations: The data collected shows that the plants that received vinegar did not
grow. The plants without vinegar grew an average of 5 cm in 2 weeks. The plants without
vinegar were tall and very bright green.
`
Parts of a Lab Report:
Discussion: (write a conclusion about whether or not the results supported the
hypothesis)
Discussion: The data collected did not support the hypothesis. The plants with vinegar did
not grow more than the plants with the vinegar.
Discussion: A conclusion can not be made because of error in the experiment. All of the
plants were destroyed by a dog.