1. Scientific Method- Senses Lab
Procedure
In pairs
One drops ruler, one reacts
Repeat each sense 5 times (5 trials), for each of the 3 senses (Sight, Touch, Sound)
Record data as you go, switch once you are finished

2. Scientific Method- Senses Lab
Catcher: Start with top of index finger at 0cm (ruler should have measurements on index finger side); fingers close to ruler but NOT touching
Highest point where index finger lands is recorded on worksheet, repeat each trial 5 times
IT IS OK if the catcher does NOT catch the ruler (null result)

3. Precise versus Accurate
Accuracy: how close a measured value is to the actual (true) value.
Precision: how close the measured values are to each other.
So, if you are playing soccer and you always hit the left goal post instead of scoring, then you are not accurate, but you are precise!
Precise but not accurate
Accurate but not precise
Accurate and precise

4. Brain 6 5 1 4 2 3 Eye 8 7 Arm ruler Biggles’ guide to…
‘Catch the ruler!’
Associative centres 5
RULER + FALLING =
What should I do ?
ruler 1 4 2
visual information
about falling ruler
Visual centres 3
Eye 8
grasping action 7
Motor command
to catch ruler
distance travelled
Arm

5. Calculating Average
For each trial you are required to calculate average or mean of your trials
Mean= T1+T2+T3+T4+T5 5
If you had a “dropped” ruler you add it as 30cm
t = d X 1000 g
Where:
t = Reaction time (milliseconds)
d = Distance ruler dropped (cm)
g = Acceleration due to gravity (980 cm/sec2)
X 1000 = To convert the time from seconds to milliseconds.
Extension: Calculate reaction time in milliseconds

6. Graphing and Reporting

7. Bar Graph
cm Drop Average

8. How did you do? DISTANCE – REACTION TIME CONVERSION TABLE Catch Catch
Distance Reaction time Distance Reaction time
(cm) (milliseconds) (cm) (milliseconds)

9. Class Data
Sight
Touch
Sound
701
#DIV/0!
702

10. Think about it…
After you’ve tested yourself, why not experiment further. Here’s a few suggestions, do reaction times vary:
for people of different ages (children versus adults)?
if you use your dominant hand versus non-dominant hand?
if you are tired or alert?
for men or women?
depending on your mood?
after an alcoholic drink?

11. Conclusion Statement- RERUN
Restate: Restate the lab experiment. Describe the assignment. (include your independent, dependent and controlled variables)
Explain: Explain the purpose of the lab. What were you trying to figure out or discover? Talk briefly about the procedure you followed to complete the lab.
Results: Explain your results. Confirm whether or not your hypothesis was supported by the results. (Use simple language such as, “The results supported the hypothesis,” or “The results did not support the hypothesis.”)
Uncertainties: Account for uncertainties and errors. Explain, for example, if there were other circumstances beyond your control that impacted the experiment (“Controlled Variables” that weren’t controlled)
New: Discuss new questions or discoveries that emerged from the experiment.

12. Some Thoughts…
generally the older you are the longer your reaction time (that ruler keeps hitting my foot!)
as you might expect, the dominant hand has a faster reaction time.
in ‘Catch the ruler’, it helps to pay attention – so being alert is a great asset.
who is faster ‘men or women’? …you tell me?
mood affects attention and therefore reaction times.
alcohol greatly increases reaction times.