A Well Designed Investigation
Catch It!
Engage in Reaction Time
• The soccer goalie on the cover page sees
the ball coming and has to move quickly to
reach and catch the ball.
• In less than a second, he must see where
the ball is traveling and know where to
move his arms, legs, and hands so he can
catch the ball before it goes into the goal.
• How can the goalie make all these
decisions so fast? (student responses)
Explore Reaction Time
• Today you will explore how quickly people
react to catch a falling ruler.
• Then, you and your partners will compare
the reaction times of different people.
Teacher Model (Procedures)
• The teacher (starter) holds the ruler vertically (straight
up and down).
• The student opens the fingers of the catching hand and
holds them near the bottom of the ruler, right next to the
“O” cm line (without actually touching it)
• Without warning, the starter lets go of the ruler and the
student (catcher) catches it by quickly pinching the
fingers around the falling ruler.
• The teacher reads the measurement on the ruler at the
point where the fingers are holding it.
• All members record the distance the ruler dropped in a
data table.
• Repeat several times.
Record Your Data
• Use the following data table to record your
reaction time for each trial (3 trials).
• Record your average reaction time for 3
trials.
• Students should work in pairs (one person
is the starter, and the other is the catcher)
• Students should collect all the data from
each member of their team
• (see data table on next slide)
Distance Ruler Dropped/Reaction
Time
Distance Ruler Fell (cm) Reaction Time (sec.)
1
.05
2
.07
3
.08
4
.09
5
0.10
10
0.14
15
0.18
20
0.20
25
0.23
Data Collection Table
See Data Table 2016
Class Data Table
• (see word document)
Analyze the Data
• Compare the class data
• Which of your subjects had the fastest
reaction time?
• What factors contributed to the different
reaction times?
• Were there any similarities among the
people with the fastest reaction times?
• List observations and questions for
research.
Data Observations
Fast Reaction Time
Traits
Slow Reaction Time
Traits
Questions For Further Research?
• What factors influence human reaction
time?
• How do your senses get information to the
brain and how does your brain respond?
• (list student questions)
Reaction Reflection
• Reaction Time Definition: The interval of
time between application of a stimulus and
detection of a response.
• Reaction time (RT) is the elapsed time
between the presentation of a sensory
stimulus and the subsequent behavioral
response
Types of Reaction Time
• Simple reaction time is usually defined as
the time required for an observer to detect
the presence of a stimulus. For example,
an observer might be asked to press a
button as soon as a light appears. Simple
RT to detect the onset of a light flash is
approximately 150 to 300 milliseconds[3].
Reaction Time in Your Body
• Stimulus 􀃆(Drop Ruler)
• Sensory Neuron 􀃆(Sends message to
spinal chord)
• Spinal Cord or Brain 􀃆(Brain receives
message)
• Motor Neuron 􀃆sends message back to
response area
• Response (the action that responds to
the stimulus)
Sensory neurons convert a stimulus into an electro-chemical signal, which
flows the length of the
sensory neuron(s), then through a neuron or neurons of the central nervous
system, and then
through the length of the motor neuron(s). Generally, motor neurons will cause
a muscle to
contract or a gland to secrete a substance. Reactions that involve only the
receptor, the spinal
cord, and the effector, are faster than those which involve processing in the
brain. Reactions
which only travel to, through, and from the spinal cord are often called spinal
reflexes or cordmediated
reflexes; withdrawing one’s hand from a hot stove is an example of such a
reflex.
Types of Reaction Time
• In ‘simple reaction time’ experiments, there is only one
stimulus and one response. Catching a dropped stick, or
hitting a button when a light changes are examples.
• In ‘recognition reaction time’ experiments, there are
symbols to respond to and symbols to be ignored.
• In ‘choice reaction time’ experiments, there are multiple
stimuli and multiple responses.
• The reaction must correspond to the correct stimulus.
• Typing a letter which matches a printed letter prompt is
an example of this type of experiment
What Affects Reaction Time?
• (list factors)-see next few slides for some
help!
Factors Effecting
Reaction Time
Setting Up
“A Well Designed Investigation”
• DECIDE: Introduce an independent variable (what you are
changing) and form a testable question and a hypothesis based
upon the control set up (ruler drop time experiment)
• DESIGN: Form a set of procedures for the experiment
• CREATE: Create a data table to organize the collection of your
dependent variables (what you are measuring or recording)
• CONDUCT: Perform the experiment and collect the data (put all
data on data table)
• CALCULATE: The average time it took each student in your group
to catch the ruler
• GRAPH: Create a bar graph that compares the average reaction
times of the students for the factor you tested
• INTERPRET THE DATA: Forma conclusion discussing how the
independent variable affected the reaction time of each person.
Present Your Findings:
Poster Rubric
• The testable question your group was
investigating is clearly visible
• A brief description of how your group did
your experiment
• A bar graph demonstrates your findings
• A conclusion is included that includes data
support