Discrepant%20events%20and%20Demonstrations

1
Discrepant events and Demonstrations
B. Law Unionville High School benjamin.law_at_yrdsb.
edu.on.ca
2
Demonstration is a scientific experiment carried
out for the purposes of demonstrating scientific
principles. Students may have learned about the
scientific principles before seeing the
demonstration.
3
Discrepant event is one that does not appear to
follow basic rules of nature. Outcome of a
discrepant event is unexpected or contrary to
what one would have predicted.
4
There is no guarantee of learning when students
observe or experience discrepant events. (They
may have ignored or rejected it)

• Some strategies are recommended
• predict the outcome
• construct one or more theoretical explanations
• observe the outcome
• modify the theoretical explanation
• evaluate competing explanations

5
Safety comes first in both discrepant event or
demonstration
6
(A-1) Singing plastic tubes Material plastic
vacuum tube / tubes from dollar store Related
to Gr. 11 physics sound unit High pitch
sound is produced when swirling a long plastic
tube
7
(A-2) Blue Bottle demonstration - The solution
will turn blue when you shake it. It will turn
back to colorless after a short while
Materials Dextrose, Potassium Hydroxide,
methelene blue indicator Related to Gr. 9/10
Science Chemistry unit
Explanation http//jchemed.chem.wisc.edu/JCESoft/
CCA/CCA3/MAIN/BOTL/PAGE1.HTM
8
(A-3) Needle-proof balloon A normal party
balloon will not pop even a sharp needle is
inserted into it. Materials Syringe/needle ,
balloons Related to Gr. 9/10 Science
Chemistry unit
9
(A-4) Fireproof balloon A normal party balloon
will not pop when it is placed above a burning
candle. Materials Candle, Balloon (with water
inside), retort stand and ring clamp. Related
to Gr. 9/10 Science Chemistry unit
10
(A-5) Colorful fireball Fireballs in different
colors will be produced when spraying the
solution on a burning candle. Materials Spray
bottles, Solution contains mineral nitrates and
alcohol Related to Gr. 9/10 Science
Chemistry unit
11
(A-6) Isopropanol / Ethanol in pop bottle
vigorous combustion reaction can be observed
Materials Isopropanol / Ethanol, dry 2L pop
bottles, candle Related to Gr. 9/10 Science
Chemistry unit
12
(A-7) Isopropanol / Ethanol in big water bottle
--vigorous combustion reaction can be observed
Materials Isopropanol / Ethanol, Empty
distilled water bottle (large size) Related to
Gr. 9/10 Science Chemistry unit
13
(A-8) Is it illegal to burn this paper bill?
Paper bill can not be burnt when it is soaked
with 50/50 rubbing alcohol. Materials
Isopropanol, 5 paper bill, candle Related to
Gr. 9/10 Science Chemistry unit
14
(A-9) Water fall ? Good way to demonstrate
the force between water molecules (surface
tension) in particle theory. Materials
Erlenmeyer flask , wire mesh, water Related to
Gr. 9 Science Chemistry unit
15
(A-10) CCD Infra-red detector IR beam can be
detected by using a digital camera/video camera.
Make the invisible become visible. Materials
Any remote control, Video camera / Digital camera
,TV/ LCD projector with video input Related to
Gr. 11 Physics Optics unit
16
(A-11) Antigravity coffee can Materials Large
Coffee can, 1 kg mass, duct tape Related to
Gr. 12 Physics Energy unit
17
(B-1) Hammering a nail into a wood over head
(Newtons 1st law) Materials Few text books,
block of wood, nail and hammer. Related to
Gr. 11 Physics Dynamics unit
18
(B-2) Hydrogen Rocket Newtons 3rd
Law Materials Empty Pringles can, Sulfuric
acid, Zinc metal, Candle. Related to Gr. 11
Physics Dynamics unit
19
(B-3) Few Bernoullis principle demonstrations
(escaping egg, jumping coins, suspending ping
pong ball, suspending squash ball) Materials
raw eggs, small paper cups, coins, 250ml beaker,
ping-pong balls, squash balls, hair dryer and
leave blower. Related to Gr. 12 Physics
Dynamics unit
20
(B-4) Centripetal force demonstration Materials
Wooden stage with strings attached to it, bucket
with water Related to Gr. 12 Physics
Dynamics unit
21
(C-1) Thats a cool pen holder Materials
Erlenmeyer flask, party balloon, electric kettle,
beaker with cold water Related to Gr. 9/10
Science Chemistry unit
22
(C-2) Sacrificing Gummy Bear Materials Sodium
Chlorate (KClO3), large clean Pyrex test tube,
retort stand and test tube clamp, one gummy bear,
Bunsen burner. Related to Gr. 9/10 Science
Chemistry unit, Gr. 11/12 Physics Energy unit
Explanation http//www.woodrow.org/teachers/chemi
stry/institutes/1988/gummybear.htm
23
(C-3) Density demonstration suspending soap
bubbles in a fish tank Materials Empty fish
tank, baking soda, a bottle of vinegar, soap
bubbles solution. Related to Gr. 9/10 Science
Chemistry unit
24
(C-4) Dying of the fire dragon -- Methane gas
Soap bobbles Materials Methane gas (Bunsen
burner gas), soap bubbles solution Related to
Gr. 9/10 Science Chemistry unit
Extra Safety Note Wet your hands prior to
handling the soap bubbles before burning
25
(C-5) Sparkling finger -- Lighting up Bunsen
burner using index finger Materials Van de
graaff generator, short plastic stool (or
inverted recycling bin), Bunsen burner Related
to Gr. 9/10 Science Chemistry unit, Gr. 11/12
Physics Electricity unit
26
THE END
Tips Try the demonstrations/discrepant events
before showing students!
27
benjamin.law_at_yrdsb.edu.on.ca