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> Solar-powered water heater
This long-term challenge is taken from the Creative
Challenge guide entitled Relevez le défi, published
by the Conseil de développement du loisir scientifique (CDLS)
All high school level students
Key words: Gravity, thermodynamics, solar energy
Space: Kitchen, laundry room or outdoors |
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Your mission |
| Your father just installed a swimming pool
in your backyard. You are planning terrific pool parties with friends
this summer. The weather office is forecasting a cool but sunny
month of June. Why not take advantage of the sun to heat the pool? |
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The challenge |
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Using a 60-W bulb, build a water heater
able to heat 1 L of water. You must also design a water circulation
system, like the one used for a pool. |
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Materials |
You can use the following materials plus an object
of your choice, as long as it is not an additional heat source:
Water container and circulation system
 Household
aluminum foil (10 m x 30.5 cm)
1 empty
1-L soda bottle
2 m of plastic
pipe (0.5 in. in diameter)
1 piece
of polystyrene (20 cm x 20 cm x 5 cm thick)
Tape
Hot glue
Modelling
clay
2 shoeboxes
Plastic
wrap (10 m x 30.5 cm)
An object
of your choice for the device
Water heater
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A cone-shaped work lamp or other light source. We have chosen 60-W bulbs for the safety of participants. |
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A laboratory or cooking thermometers. Cooking thermometers are preferable if you create your devices at home and want to test them. |
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A nearby source of water or a container large enough to hold water to be heated. |
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A stopwatch or an accurate clock (e.g. a photography lab clock or cooking timer) |
Warning: For your own safety, no source of heat other than the
lamp should be used. Never use a bulb stronger than 60-W.
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A few rules |
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Use a 1-L soda bottle to hold the water to be heated. |
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Allow a distance of 20 cm between the bottle and the heating system. These dimensions do not include the water heater. |
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Install a 60-W bulb on a cone-shaped metal desk lamp. |
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The test |
You
have five minutes to set up your device.
Place the
thermometer in the water bottle.
Once the
lamp has been turned on, you can no longer intervene.
Begin timing
as soon as the bulb is lit.
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Measure the water temperature after three minutes, than after ten minutes, then every minute until the 20 minutes are up. Depending on your assembly, you may wish to record the temperature every minute, if the water heats up quickly. |
Don't forget
to record the results after each reading.
When the
20 minutes are up, tabulate the results.
If you do this challenge with friends
The
measurements must be taken at the same times for all participants.
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If this is not possible, stagger the starting times in order to take the three measurements. |
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To ensure that the bulb gives off the same heat for every participant, it should be changed for each one. Provide as many new 60-W bulbs as there are participants. |
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How to award points |
We suggest that the scores be calculated in three stages
in order to recognize devices that are less effective in the long-term,
but that can lead to discussions once the competition is over.
Highest
temperature after three minutes: 20 points
Highest
temperature after ten minutes: 30 points
Highest
temperature after 20 minutes: 50 points
In each case, the second-place player will earn two points less, the third-place
player will earn 4 points less and so on.
For example, the team with the second highest temperature after three minutes
scores: 20 points – 2 points = 18 points. If that team has the highest
temperature after 10 minutes, it scores 30 points. If that team has the
third highest temperature after 20 minutes, it scores 50 points –2
points – 2 points= 46 points. Total points: 18 + 30 + 46 = 94 points
Participants with the same temperatures score the same number
of points.
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The science behind the challenge |
This long-term challenge is interesting because there
are two parameters that must be taken into account: gravity and thermodynamics.
You will become familiar with water heating systems similar to those used
in pools.
Use the concept of solar energy to tackle the challenge and see whether
you can draw correlations between this and other fields of science.
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Want to know more? |
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ARDLEY, Neil. How things work. London, Dorling Kindersley. (Note: The idea for this challenge was taken from the water heater illustrated on pages 58-59). |
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Do a library or on-line search using the key words at the beginning of this challenge. |
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Click on the icon to access the printable PDF format version.* |
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Click on the icon to send a message to a friend. |
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> Let the turbines spin!
This long-term challenge is taken from the Creative
Challenge guide entitled Relevez le défi, published
by the Conseil de développement du loisir scientifique (CDLS)
Primarily for Secondary I and II students
Key words: Dynamo, electricity, hydroelectric plants, hydraulic
turbine, wind energy, clean energy
| Space: |
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Wind plant: a room with NO water source |
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Water plant: a room with a water source |
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Your mission |
| As part of its support program for developing
countries, the UN is holding a contest to build small hydroelectric
plants. Each one must be able to supply electricity to a village
of 2000 inhabitants. |
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The challenge |
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You must build a small hydroelectric plant
able to supply power to a series of small neon lights connected
to a dynamo (a machine converting mechanical energy into electrical energy). You must create a system that will activate the dynamo
using either wind or water. |
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Materials |
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1 bicycle dynamo or any other system able to produce electricity. Regardless of the type of system, make sure you know the size of the rod that you will use to connect the system. |
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Be sure that the system operates on low voltage. If the system exceeds 12 V, the systems may not work. If you have a dynamo, make sure that it is working well and is properly lubricated. |
Small coloured
neon lights (available in electronics stores)
1 electric
wire to connect the neon lights to the dynamo
1 plate
to hold the dynamo
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Additional materials for the water-powered systems |
5
L of water
A single
bottle to pour the water (e.g. a large vinegar bottle)
A large
basin to collect the water (e.g. large garbage pail)
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Additional materials for the wind-powered systems |
A 3-speed household fan with 30-cm blades.
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A few rules |
For a water-powered plant
Your
system must be no larger than 30 cm x 30 cm x 30 cm.
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These dimensions do not include the dynamo, the drainage system (the 5-L bottle), the water recycling system or the rod used to connect your system to the dynamo. |
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You must build your system from scratch. Any machine operated parts must be taken from objects used for purposes other than producing electricity. |
Your system
must be able to activate a bicycle dynamo.
Always use
the same bottle to pour the water.
For a wind-powered plant
Your
system must be no larger than 30 cm x 30 cm x 30 cm.
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These dimensions do not include the fan or the rod used to connect the system to the dynamo. |
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Your system will be connected to a bicycle dynamo. |
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You can choose the desired speed, but the fan must remain 20 cm from your system. |
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Decide what container you will use to collect the 5 L of water. Calculate the time it takes to pour out the water and allot the same amount of time for the use of the fan. If, for example, it takes 30 seconds to empty the water bottle, the fan will remain on for 30 seconds |
Warning: Your system cannot be powered by both wind and water.
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The test |
Divide testing into three stages:
Stage
1: Connect two neon lights to the dynamo. If they light up = 30 points
Stage 2:
Connect four neon lights to the dynamo. If they light up = 65 points
Stage 3:
Connect six neon lights to the dynamo. If they light up = 100 points
To evaluate
your performance, award points for every light that is lit.
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You can also calculate the time that a particular light remains lit. This should be a secondary factor, since the differences are likely to be quite small. |
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In the event of a tie, you can always add more neon lights or other light sources after the first three stages have been completed. Add ten points for each additional light that is lit. |
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The science behind the challenge |
This challenge is fun because it doesn’t require
in-depth scientific knowledge. You can, of course, discuss more challenging
concepts, but the aim here is to develop a basic understanding of electricity
and become familiar with the different sources of energy. Once the challenge
is over, discuss the advantages of hydraulic vs. wind energy. Which is
the cleanest? Which is the most efficient?
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Want to know more? |
Do a library or on-line search using the key words at the beginning of this challenge.
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Click on the icon to access the printable PDF format version.* |
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Click on the icon to send a message to a friend. |
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> Fresh-water flask
This long-term challenge is taken from the Creative
Challenge guide entitled Relevez le défi, published
by the Conseil de développement du loisir scientifique (CDLS)
All high school levels
Key words: Gravitational energy, gravitational force
Space: Small room |
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Your mission |
| It’s not easy transporting water,
especially when you’re surrounded by obstacles. This time,
you have to safely transport water in a flask from a reservoir to
quench the thirst of a population living in the desert. |
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The challenge |
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You have three minutes to empty 2 L
of water contained in a flask placed on a square table measuring
75 cm x 75 cm x 70 cm high into a tank placed
at the end of another table measuring 75 cm x 75 cm
x 75 cm high and located 50 cm from the first table. |
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Materials |
1
table measuring 75 cm x 75 cm x 70 cm high
1 table
measuring 75 cm x 75 cm x 75 cm high
Spherical
flask only
Funnel
1 stopwatch
or timer
1 table
to record results
1 graduated
2-L container to fill the flask with water (e.g. empty soda bottles)
1 2-L graduated
cylinder to empty water from the flask
Supplies
to clean up spills (you’ll need them!)
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A few rules |
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It’s up to you to decide how to empty the flask of water, but you cannot transport the water from one table to the other yourself. |
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You or a team member can activate the mechanism, provided this intervention lasts no longer than five seconds. |
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Any bridge between the two tables must be installed by the mechanical system. |
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No bridges can be erected between the two tables before or after the mechanism is activated. |
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The tables cannot be moved. |
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Once the mechanical system for emptying the flask has been activated, the whole process must be completed within three minutes. |
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At the beginning of the experiment, the flask can be placed anywhere on the lower table. |
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The water from the flask emptied will be measured in a graduated cylinder. |
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The test |
Place
the flask on the lower table.
Using a
funnel, empty 2L of water into the flask.
Start the
stopwatch at the starting signal.
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After three minutes (or before, depending on the case) measure the volume of water collected and record the result in the designated table. |
The team
with the greatest volume of water will be declared the winner.
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Want to know more? |
Do a library or on-line search using the key words at the beginning of this challenge.
|
Click on the icon to access the printable PDF format version.* |
|
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Click on the icon to send a message to a friend. |
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> Airborne clown!
This long-term challenge is taken from the Creative
Challenge guide entitled Relevez le défi, published
by the Conseil de développement du loisir scientifique (CDLS)
All high school levels
Key words: Simple machines principles
Space: Large room or corridor |
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Your mission |
| The life of a circus clown can be rough.
The Genius Circus clown is really tired but is afraid of taking a rest. Why? His instructions are very clear: he can take a nap
only if he is propelled directly into his bed. However, if he doesn’t
hit the target (the mattress) he can end up in the lion pit! Using
your creativity, can you find a way to help this poor clown get his
much needed rest? |
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The challenge |
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You must build a device that will displace
a golf ball, using the principles of simple machines. The golf ball
must be able to propel the clown into his bed. Collect the most
points by hitting the target in this two-round contest. Your device will be located 1.5 m from the target during the first round and 2 m from the second. |
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Materials |
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1 wooden dowel 15 cm long and 2 cm in diameter |
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Cardboard for the circles that will make the target |
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3 5-kg bags of sand |
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1 plastic sheet or something to collect the sand |
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Material of your choice for the mechanism |
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Golf ball to activate the mechanism |
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Elastic bands,
levers under tension or springs are not considered simple machines.
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A few rules |
Target
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To prepare for both stages, cut out eight circles with a contour 8 cm deep and a diameter of 40, 60, 80,100, 120, 140, 160 and 180 cm. |
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Number each circle with the amount of points they are worth : 30, 40, 50, 60, 70, 80, 90 and 100 points. |
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When arranging your target, gently press the circles that you need in the bed of sand. |
Device
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You must build your device from scratch. You cannot use manufactured machines. |
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The device must be no larger than 1 m high x 1 m long x 0.5 m wide. |
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The device will be placed on a table of standard height (76.2 ± 2 cm). |
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Your device must have a platform on which to place the clown. You must place the clown on the platform at the end of the final mechanism in your device. Note that the method of propulsion will vary from one mechanism to the next depending on the last mechanism used. |
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Your device must combine at least three principles
of simple machines. You will not earn extra points for combining
five principles. It is important to respect the minimum. |
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You cannot push or throw the ball. Simply place it in such a way that it activates the mechanisms.
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The test |
You
have two minutes to install the device in the competition area.
You cannot
intervene once the ball is in place.
Quickly measure
the distance of the dowel from the bull’s-eye.
First round
For
this stage, place the bull’s-eye at a distance of 1.5 m.
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The target will be comprised of four circles with a distance of 20 cm between each circle. |
The bull’s-eye
has a diameter of 40 cm.
The four circles
are worth 40, 60, 80 and 100 points.
Second round
For
this stage, place the bull’s-eye at a distance of 2 m.
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The target will be comprised of eight circles with a distance of 10 cm between each circle. |
The bull’s-eye
still has a diameter of 40 cm.
The eight circles
are worth 30, 40, 50, 60, 70, 80, 90 and 100 points.
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For several players |
In the event of a tie after the two rounds, calculate
the distance of the clown from the bull’s-eye. If, for example,
you are in the 80-point circle and 35 cm from the bull’s-eye and
another team is in the 80-point circle and 38 cm from the bull’s-eye,
your team will be declared the winner.
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Want to know more? |
Do a library or on-line search using the key words at the beginning of this challenge.
|
Click on the icon to access the printable PDF format version.* |
|
|
Click on the icon to send a message to a friend. |
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* If you do not have Acrobat Reader, click on the icon : 
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© 2002, Conseil de développement du loisir scientifique
(CDLS). This document is distributed by the Conseil de développement
du loisir scientifique.
For more information, visit our Web site at www.cdls.qc.ca. |
The opinions
expressed in this section are those of the authors and do not
necessarily
reflect the opinions of Merck Frosst or its employees. |
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Household
aluminum foil (10 m x 30.5 cm)
