Energy and the Environment Hands-On Activities
Workshop W21
AAPT 2012 Winter Meeting, Ontario Ca
John Welch
The activities in this workshop were developed by John Welch for the Cabrillo College
Summer Energy Academy, a 4-week summer intensive course designed to help attract
beginning college students to STEM fields as well as to increase their ‘energy literacy’. The
Cabrillo Energy Academy is part of a larger NSF funded program at Cabrillo called
STEEP. The activities were designed to maximize both fun and educational value and to
use relatively unspecialized equipment. Please make improvements to these activities and
modify them to fit your situation. Please share them with your colleagues as you see fit. I
would love to hear about your experience with the activities and about the improvements
you’ve made.
Contact info:
My email: jowelch@cabrillo.edu
More info on my website: www.cabrillo.edu/~jwelch/aapt.html
Cabrillo STEEP Project: www.cabrillosteep.org
Youtube video of Energy Academy: www.youtube.com/watch?v=b_5XlAE9mRI
Peak Oil Game
Concepts and skills taught:
Production inevitably peaks before oil ‘runs out’
Production becomes more difficult as the ‘easy to reach’ oil is used up first.
Graphing data in Excel.
Materials needed: 1/4 teaspoons, ½ teaspoons, teaspoons, tablespoons, long handled spoons, larger
spoons, litter box scoopers, large bag of black beans (25 lbs?) and of garbanzo beans, 24 jars, 2-3 digital
scales (1000 g capacity), paper, notebooks, 30 second timer with alarm, small measuring cups, 3 small tubs
per team (or paper bags) and 2 larger tubs for the room.
Teams of 3-5 students each.
Game Goal: Teams are told that the team that ‘drills’ the most oil in the 10 year period is the winner. This
motivates them to try hard and makes it fun, but this goal doesn’t have much to do with the real educational
goals, as the students will see later.
To start – each team starts with one person as ‘driller’ and one person as ‘processor’. Each team has a set of
jars (oil field), a small spoon (1/8 teaspoon), and 3 containers (1 for processing oil, 1 for processed oil, and 1
for accumulated oil). There are a few larger bowls for group use and a depository of ‘tools’.
The jars contain black beans (oil), garbanzo beans (dirt, contaminate), and rocks. This is their “oil field”. They
can mine the oil from any jar in any order. The “oil” gets more and more diluted toward the bottom of the jars,
so they get less and have to do more processing as they go deeper. Also, there may be obstacles in bottoms of
jars, like rocks. They cannot pick up the jars, lean the jars over, use their fingers to extract beans, or pull out
the rocks. They are limited to using their spoons to scoop beans out of the jars.
Each round of the timer (30 seconds) is one “year”.
During each ‘year’, the goal is to get as much clean oil into the team’s ‘processed oil’ container as possible.
Penalties are charged for contaminated oil and for oil spilled outside the containers. Each team also has a bag,
box or tub that they can use as an intermediate ‘processing plant’ in which to glean out garbanzo beans. The
processing must take place along with the drilling and stop after the 30 second timer goes off.
When the timer goes off, all activity stops immediately and the following things happen (in order)
1) Penalties:
-dirt in the clean container: For each garbanzo bean in the clean container, remove two black beans
(along with the garbanzos).
- spilled oil: For each black bean spilled outside the containers, remove two black beans from the
clean container.
(these amounts can be estimated rather than having to make exact ‘bean counts’)
2) Discard all spilled and unprocessed oil into the communal waste container.
3) Measure the year’s production. Weigh the beans that remain in the clean container after the penalties and
record that year’s production in the team’s notebook.
4) Add the current year’s harvest to the team’s accumulated storage container. They will use this stored oil to
purchase tools and employees.
5) Buy better tools and hire more staff. Teams use their accumulated inventory of oil as cash to buy new
equipment and hire people. It’s best to have a set ‘price’ (like say 1 tablespoon oil to start with) for either a
new state-of-the-art tool or a new employee. After each round, the instructor announces the latest technology
(say a ½ teaspoon) and the current price, which should rise as the teams get richer.
Game goes on for 10ish years – depending on the interest level of the students. It’s important to keep it going
long enough so that each team’s production has started to decline.
Groups use excel or graph paper to graph yearly production.
Dicuss the shapes of the graphs. Talk about the peaks.
Compare to real oil production graphs, for US and world oil production.
(http://tonto.eia.doe.gov/dnav/pet/hist/mcrfpus2a.htm)
Questions for discussion:
Did the oil actually run out?
What percent of the original oil is left, roughly?
In what ways is this model similar to the real world?
In what ways is it different?
oil production
700
production in grams
600
500
400
300
200
100
0
0
2
4
6
8
10
12
year
Actual US Oil Production Data
Typical Student Data
World Production from Wikipedia
World Non-Opec Data
World Production on a larger time
scale.
Wind generator activity
Concepts and skills taught:
What variables are involved in designing wind generator blades?
How is power output measured? (Volts only?, Amps only? or Watts?)
How big is a Watt?
Doing experiments: adjusting variables and carefully documenting the results.
How to use a digital multimeter.
Having a fun experience while doing science/engineering.
Materials:
-Blade material – cardboard, manila folders, plastic sheet, etc
-Gearbox Motors - available at Edmund Scientific ($20)
http://scientificsonline.com/product.asp?pn=3039118&bhcd2=1248567029
-Plastic corks
-1/16 inch welding rod, or other stiff wire (could maybe use toothpicks?)
-Strong fan
-Multimeters
-1.5 V flashlight batteries for load
- Tools to cut out blades
- Wire (banana leads?) to connect generators to lights and multimeters
-Hot glue guns or other glue to connect rods to blades.
Activity:
Teams of 2 – 3 students.
Instructor demos the general design to students.
Instructor discusses how to measure power output of a wind generator and how to use a multimeter
if students have not used them before.
Group discussion to generate a list of variables that might be involved in turbine blades:
- length
-width
-number of blades
-‘pitch’ of blades
-material
-gear ratio of motor
Teams are given 2 – 3 hours to design, build and test various blade configurations. Blades are cut
out of cardboard, plastic sheet, manila folders, etc. Two (or could try just one) 4 inch lengths of 1/16
inch welding rod are hot-glued onto blades to allow them to be poked into the cork hub at any angle.
If students have trouble poking rods into cork, it helps to use an awl to pre-poke the holes. If you use
one rod per blade instead of two, then you can adjust the pitch of the blade without removing the
blade from the hub –just make sure that there is enough friction so that it doesn’t get loose when the
turbine spins.
Students should record all findings in an organized fashion in notebooks.
At the end of the class, each team gives an oral presentation to the class on their findings.
Hints:
2 -3 blades seem to be best.
Narrow long blades are good.
Balancing the blades on the hub is important. (instructor should pre-drill holes in corks to make sure
they are centered.)
Using two gears on the gearbox seems best. (More than two gears is too much.)
Have one testing setup near fan where students can easily connect their generators.
Gearbox Motor available at Edmund Scientific ($20)
http://scientificsonline.com/product.asp?pn=3039118&bhcd2=12485
67029
Plastic corks used for hub. 1/16” steel welding rod pieces hot-glued
to blade poke into the hub.
Grid Model Activity
Concepts and skills taught:
The power grid does not currently include any storage.
Power generation must constantly be adjusted to the current demand, or load.
We can’t generate enough power to supply all possible loads simultaneously, but instead we strive
to meet ‘peak demand.’
When generation falls short of demand, the voltage drops and we get ‘brown outs.’
Power companies continually adjust the ‘mix’ of power sources, depending on time of day, year, and
based on cost.
Power is lost when transmitted long distances.
Power plants and loads are all connected basically in parallel.
Centralized vs distributed power.
The idea of a simplified model as a learning tool.
What is the ‘smart grid?’
Materials:
Hand cranked DC generators, such as ‘Genecon’.
6V Flashlight bulbs
Spring ‘junction boxes’.
‘zip cord’
Voltage display – via Vernier or Pasco interfaces, or some other meter.
Activity:
Instructor sets up the model grid like this:
There should be enough bulbs so that all the generators working together don’t have enough power
to fully light all the bulbs.
Have some power stations far away on very long wires (nuclear power is good for this) .
Have at least two banks of bulbs at different locations to represent different towns or neighborhoods.
Students are assigned different roles: nuclear power plants, solar power plants, wind power, coal
power, and consumers.
Depending on class size and materials available, each type of power can have several hand crank
generators in parallel, so that that the different types of power can be ‘ramped up’ or down. (Power
plants not currently in use should disconnect so that they don’t become loads as motors.)
Activities:
System voltage and ‘brown outs’:
Start with a medium sized load (2-3 bulbs in parallel) and one ‘power plant’ and discover with the
class how much voltage is needed to keep them fairly bright. Decide on what the nominal voltage for
this model should be.
Now screw in more bulbs and notice with the class that the voltage goes down and the lights go dim.
Ask the student with the generator if it gets harder to turn the crank.
Ask students if they have heard the term ‘brownout’.
Parallel configuration:
Show students that any of the lights can be powered by any of the generators – because everything
is connected in parallel.
Transmission Losses:
Try one power source at a time, lighting a few bulbs at the front of the room. The generator that is
farthest away should have trouble keeping the voltage high enough. Ask – why? (you can put a
resistor in their line if you need in order to ‘fake’ the power loss situation.)
Sizing of generation facilities:
Screw in all the bulbs and see if all generators working together can power them. (should not be
possible) Ask – is this a realistic model?
Response to changing demand:
Have multiple sources of power going (coal team, wind team, etc.) , keeping the system it it’s rated
voltage. Then have ‘consumers’ change the number of bulbs that are screwed in, and make
generators have to respond to try to keep the voltage constant. Discuss – how might real power
companies do this?
Mix of power sources:
Make up different scenarios and ask students what would be the best mix of power sources.
For example: “Now it’s evening in January on the east coast.” – “Now it’s noon in Florida in July”,
“Now it’s midnight in California in March.” and have them discuss which power sources to use first.
Energy Lab Activities (Physics 10 level)
1) Energy Units
When we talk about energy, we use many different kinds of units, depending on the situation.
The most common units of energy we use are Joules, calories, kilocalories, and kilowatt-hours.
In this section, you’ll get a sense for how large these are and how they compare to each other.
a) Joules. A Joule is defined as the amount of energy it takes to pull (or push) on something with
a force of 1 Newton for a distance of 1 meter. The aluminum cylinder weighs about one
Newton. Try lifting it up from the floor to the counter and you’ll see what a Joule of energy feels
like. Is that more or less than you would have guessed?
b) Calories. A calorie is the amount of energy it takes to warm up a milliliter of water exactly 1
degree Celsius. We have a milliliter of water on the counter so you can see how much that is. A
calorie is about 4 times bigger than a Joule. To see how much a calorie is, raise the weight
marked “calorie” a meter.
c) Kilocalorie, or Kcal. When you read the number of calories in some kind of food, the
“calories” they’re talking about are really kilocalories (also known as “food calories”), which
equal to 1000 regular calories. To store a kilocalorie, you would have to lift 2 large drums full of
water up to the counter. Another way to do it would be to lift a 10 kg mass up to the counter 40
times! Try it. A lot, isn’t it?
Now you might ask yourself whether you just burned off a calorie of food by doing that work.
You actually burned off a lot more than that, because our bodies, like any machine, are
inefficient and we have to burn three or four food calories to do one calorie of useful work.
2) Power Units:
Power is a measurement of how fast energy is being stored up or used (so it’s a rate). If we use
money as an analogy, I could say “I saved $1000”. That would be like an amount of energy. If I
said “I saved $100/mo, that would be a rate.
Watts. The most common unit of power is the Watt. A Watt is a rate of energy consumption of 1
Joule per second. A fluorescent light bulb might use about 10 Watts. The power plant at Moss
Landing generates about 2000 Megawatts, or 2000 million Watts. Cabrillo is hoping to build a
huge array of solar panels that will generate 1 Million Watts (1 Megawatt.)
If you like cars, you will want to know that 1 horsepower = 746 Watts. In Part 3 you will
measure your own power.
a) Power used by appliances. Look at the various appliances to see how much power they take.
Find the label that shows how many watts it takes. You can also use the Kill-a-Watt meter to
measure their power usage. (push the grey button marked W until the display says watts.)
-Which one uses the most? Which one the least?
-Which ones do you think you would be able to power yourself?
-Did any of them surprise you?
b) Different Kinds of Light bulbs. The LED bulb is using about 2 Watts. The Compact
fluorescent bulb is using about 10 W. The incandescent bulb is using about 40W. Some of this
energy comes out as visible light, and some comes out as heat.
-Which form of light do you think is most efficient? (That is, which one converts most of its
energy into visible light rather than heat?)
3) Your Power: stairs!
Power is the rate at which something does work or releases energy. Appliances like motors or
light bulbs are releasing energy constantly, so instead of asking “How much energy did that
motor generate?”, we usually ask “How much energy (Joules) does that motor generate per
second? This is power.
An old fashioned light bulb may convert electrical power into light and heat at a rate of 100
watts—and your body converts food energy into movement and heat at about 100 watts when
you are being a couch potato. Another way of measuring it is that you use about 2000 food
calories per day just to keep yourself warm. When you exercise, you can increase this rate by up
to 10 times!
a) Use the Newton-o-Meter bathroom scale to measure the weight of each member of your
group
Record your weight in Newtons here:
b) Take a measuring device, a stopwatch, and pen and paper, and go outside. Find a nice long
flight of stairs. Measure the height of each stair and count them.
Height of each stair: __________cm x Number of stairs ______ =
________cm
Total height
To get the height in meters, divide your number by 100. Total height =
____________________ m
c) Run up the stairs while a teammate times you. Do it two or three times to get an average
value.
My times ________________
__________________
_________________
Average: ________________________
d) Work done by you: Your weight in Newtons times the vertical height in meters of the
stairs:
Be careful to get the units right here. A Newton times a meter is a Joule.
My work: ____________________________________________________Joules
Since there are 4000 Joules in a food calorie, divide your work in Joules by 4000 to get the
number of food calories it took to climb the stairs. Actually, you probably burned off about 4
times this much food to climb the stairs, because your body (or any one else’s) is not very
efficient.
Food Calories burned running up stairs:
e) Power produced by you: Your work in Joules (part d) divided by my fastest time in
seconds it took:
Joules divided by Seconds = Joules/sec = WATTS.
My Power:
_______________________________________________________________Watts
f) Did you produce over 100 watts? I hope so! A Horsepower (Hp) is 746 watts. Now figure
out how many horsepower you did:
Your power in horsepower =
Power in Watts / (746 Watts/H )
=__________________________HP
g) How long do you think you could keep up that power output until you pooped out?
-What level of power do you think you could sustain for 2 hours?
h) What two things could you do to increase your power? Feel free to try. Report what
happens. Who in your group is the most powerful?
i) Where did the energy come from to get you up the stairs? Where was it before that? Trace it
back as far as you can.
4) Your Power: Bicycle
a) Fluorescents. On the light box, set the switch on the side to Compact Fluorescent. Turn on all
the bottom switches and pedal the bike to feel how much energy these bulbs take.
b) Incandescents. While still pedalling, have someone switch the side switch to “incandescent”.
What do you notice?
c) Sustainable Power level – what power level could you sustain for an hour? Turn off some of
the bulbs until you find a level you think you could keep up a whole hour. Try doing it for 1
minute on the clock and see if you still agree with your first guess. How many Watts is it ?
________
5) Cost of Energy. (do the bike station before doing this one.)
When PGE charges you for electricity, they charge in units called Kilowatt-hours. (abbreviated
kWh) This is the energy you would use by pedaling at a rate of 1000W (= 1kiloWatt) for 1hour.
Let’s estimate how much one kilowatt-hour would cost if you had to create it with a bike.
About how many people would have to pedal together to put out 1000 Watts? (hint: remember
how much power you produced in part 4). _______________
If they had to do this for a whole hour, about how much would you have to pay them altogether?
_________
What’s your guess for how much PGE charges for this amount of energy – (1 kilowatt-hour)?
$_________
Now look at the sample PGE bill and write down the actual cost of 1 kWh: $__________
How do you think it’s possible to get so much energy for this much money? ______________
The average household in the US consumes about 30 kWh of electrical energy every day!
7) Forms of Energy and Conversion
Energy is constantly being converted from one form to another, but in any conversion, we find
that the total amount of energy stays the same. We’re so confident that this is always the case
that we call it a “law”: the Law of Conservation of Energy. Another “law” says that in every
kind of energy conversion, some amount of the energy gets converted into “not useful” heat
energy.
Look at each of these situations and name the initial form of the energy (gravitational potential
energy, chemical potential energy, light energy, electrical energy, kinetic energy, etc.) Then see
if you can identify each form the energy takes as it is converted into its final form. Also identify
places where energy is converted into heat energy.
Here’s an example, using the roller coaster at the Boardwalk:
a) Hydrogen Fuel Cell - Turn on the switch and watch the propeller turn. Look at the apparatus
to see all the different energy conversions.
b) Falling weight lights a light bulb – wind up the string around the generator wheel and then
let it fall. The light bulb should light up.
c) Lifting a mass – connect the wires to the motor and watch it lift the mass. (reverse the wires
to lower it back down when you’re done.)
8) Efficiency of Energy Conversions
Here is a little story for this activity:
Your Aunt Mabel lives in Colorado and is in need of some energy to help her lift her piano to the
2nd floor of her house. You decide to help her out by producing some energy and sending it to
her over the power lines. To produce the energy, you lift some heavy weights up from the floor.
As they fall down, they generate electricity that you send to your Aunt Mabel. You think that
some energy might get lost along the way, so you lift a weight that is 10 times heavier than her
piano, just to be safe.
Try this out and create an energy flow diagram like you did in part 5 above.
To get the efficiency of the process, we need to know how much energy you put in and how
much you got out. For this activity, we’ll measure energy by multiplying the weight of the object
times the height it was lifted.
Lifted weight =
10 units
Height lifted = __________
Energy put in = (weight x height) ____________________
“Piano”: weight = 1 units
Height raised = ___________
Energy gotten out = (weight x height) ____________________
To calculate the efficiency, divide the energy gotten out by the energy put in:
Efficiency = (Useful Energy gotten out) / (Energy put in)
(you can multiply the answer by 100 to make it a percent if you want)
The efficiency of this conversion was about ___________________.