Transcript The CrickSAT Mission connections to math, electricity and electronis

Making connections with math and basic
electricity, and electronics
Why is math important?
 Read the article “Math Mistakes in History: The
Mars Climate Orbiter”
http://threesixty360.wordpress.com/2007/11/14/math-mistakes-in-history-the-mars-climate-orbiter
 Explain what went wrong with the Mars Climate
Orbiter.
/
On 9/23/On 9/23/99, $125,000,000 Mars Climate Orbiter entered
Mars’ atmosphere 100 km lower than planned and was destroyed by
heat.
99, $125,000,000 Mars Climate Orbiter entered Mars’ atmosphere
100 km lower than planned and was destroyed by heat.
1 lb = 4.45 N
“This is going to be the
cautionary tale that will be
embedded into introduction to
the metric system in elementary
school, high school, and college
science courses till the end of
time.”
What is scientific Notation?
 Scientific notation is a way of expressing really big
numbers or really small numbers.
 It is most often used in “scientific” calculations where
the analysis must be very precise.
Why use scientific notation?
 For very large and very small numbers, these numbers
can be converted into scientific notation to express
them in a more concise form.
 Numbers expressed in scientific notation can be used
in a computation with far greater ease.
 Mass of Proton:
 .00000000000000000000000167 grams
 Number of electrons passing by a point in a circuit:
 6250000000000000000 electrons per second
Scientific notation consists of two
parts:
 A number between 1 and 10
 A power of 10
N x 10x
Are the following in scientific notation?
Changing standard form to
scientific notation.
To change standard form to scientific notation…
 Place the decimal point so that there is one non-zero
digit to the left of the decimal point.
 Count the number of decimal places the decimal point
has “moved” from the original number. This will be
the exponent on the 10.
 If the original number was less than 1, then the
exponent is negative. If the original number was
greater than 1, then the exponent is positive.
Example 1
 Given: 289,800,000
 Use: 2.898 (moved 8 places)
 Answer: 2.898 x 108
Example 2
 Given: 0.000567
 Use: 5.67 (moved 4 places)
 Answer: 5.67 x 10-4
Practice
 Use the link below to practice converting standard
form to scientific notation.
 Converting to Scientific Notation
Changing scientific notation
to standard form.
To change scientific notation to standard form…
 Simply move the decimal point to the right for positive
exponent 10.
 Move the decimal point to the left for negative
exponent 10.
(Use zeros to fill in places.)
Example 3
 Given: 5.093 x 106
 Answer: 5,093,000 (moved 6 places to the right)
Example 4
 Given: 1.976 x 10-4
 Answer: 0.0001976 (moved 4 places to the left)
Practice
 Use the link below to practice converting scientific
notation to standard form.
 Converting to Standard Form
Even More Practice
 Below is a list of links to games and activities all having
to do with scientific notation.
 http://www.aaamath.com/dec71i-dec2sci.html
 http://janus.astro.umd.edu/cgi-bin/astro/scinote.pl
 http://www.sciencejoywagon.com/physicszone/lesson/
00genral/dectosci.htm
Now take the quiz to test your
scientific notation skills!
 Click on the link below to take the quiz and then use
the answer key for the correct answers.
 Quiz
 Answers
Metric Prefixes
Metric Prefixes
I can rearrange equations to solve
equations for specified variables.
 What is the equation for solving for speed?
 Can you rearrange the equation to find distance?
 Can you rearrange the equation to find time?
The CrickSAT Mission
 Reflection: Write a reflection paragraph that includes
your understanding of the following questions.
 The CrickSAT Mission data analysis relies upon your
ability to collect the data, put into its appropriate
forms and to calibrate the information correctly.
Based upon what you have learned about basic math in
the first lesson, explain the importance of being able
to calculate and use basic mathematics correctly.

End of Importance of Math Basics
Connecting Satellites and Electronics
All you need to be an inventor is a good imagination
and a pile of junk.
-Thomas Edison
To understand electronics we must review basic
electricity.
What is Electricity?
 Everything is made of atoms
 There are 118 elements, an atom is a single part of an
element
 Atom consists of electrons, protons, and neutrons
 Electrons (- charge) are attracted to protons (+ charge),
this holds the atom together
 Some materials have strong attraction and refuse to
loss electrons, these are called insulators (air, glass,
rubber, most plastics)
 Some materials have weak attractions and allow
electrons to be lost, these are called conductors
(copper, silver, gold, aluminum)
 Electrons can be made to move from one atom to
another, this is called a current of electricity.
 Surplus of electrons is called a
negative charge (-). A shortage
of electrons is called a positive
charge (+).
 A battery provides a surplus of
electrons by chemical reaction.
 By connecting a conductor from
the positive terminal to negative
terminal electrons will flow.
In your CricketSAT Mission Notebook In the Electronics Tab Create a Table to
organize the variables and specific characteristics of each.
Always put your name and date at the top of your table.
Quantity
Definition
Symbol/varia
ble
equation
Unit of
measure
Resistance
Current
Voltage
How you should be thinking
about electric circuits:
Voltage: a force that
pushes the current
through the circuit (in
this picture it would be
equivalent to gravity)
Voltage
 A battery positive terminal (+) and a negative terminal (-). The
difference in charge between each terminal is the potential energy
the battery can provide. This is labeled in units of volts.
Water Analogy
How you should be thinking
about electric circuits:
Current: the actual
“substance” that is
flowing through the
wires of the circuit
(electrons!)
Current
 Uniform flow of electrons thru a circuit is called current.
WILL USE CONVENTIONAL FLOW NOTATION ON
ALL SCHEMATICS
How you should be thinking
about electric circuits:
Resistance: friction that
impedes flow of current
through the circuit
(rocks in the river)
Resistance
 All materials have a resistance that is dependent on cross-
sectional area, material type and temperature.
 A resistor dissipates power in the form of heat
Ohm’s Law
I=V/R
Georg Simon Ohm (1787-1854)
I
= Current (Amperes) (amps)
V
= Voltage (Volts)
R
= Resistance (ohms)
Ohms law
 defines the relationship between voltage, current and resistance.
 These basic electrical units apply to direct current, or alternating
current.
 Ohm’s Law is the foundation of electronics and electricity.
 This formula is used extensively by electricians.
 Without a thorough understanding of “Ohm’s Law” an electrician
can not design or troubleshoot even the simplest of electronic or
electrical circuits.
 Ohm established in the late 1820’s that if a voltage was applied to a
resistance then “current would flow and then power would be
consumed”.
Ohm's law magic triangle
Voltage = E or V
Current = I
Resistance = R
Ohm’s Law
If you know E and I, and wish to determine R, just eliminate R
from the picture and see what's left:
If you know E and R, and wish to determine I, eliminate I and see
what's left:
if you know I and R, and wish to determine E, eliminate E and see
what's left:
The force
or
pressure
behind
electricity
variable
Symbol
and
Unit
Ω = Ohm
milliamp or just mA
Conversions of units
•As a milliampere (milliamp or just mA) is 1/1000th of an ampere, we
can convert mA to Amps by just dividing by 1000. Another way is to take
the current in mA and move the decimal to the left three places to
accomplish the division by 1000. Here's the scoop:
275 mA / 1000 = 0.275 Amps
•Note that the decimal in 275 is to the right of the 5, and it's written as
275.0 (with a 0 added to show where the decimal is). Moving the
decimal to the left three places gets up to .275 Amps, but we usually
hang a 0 in front of the decimal.
•To convert Amps to milliAmps, just multiply by 1000 or move the
decimal to the right three places. Just the opposite of what we did here
to convert the other way.
Power
Definition
Variable
Equation
unit
Depends
on
Electrical Power
 Power is the rate of using or supplying energy:
 Power = Energy / Time
 Power is measured in watts (W)
Energy is measured in joules (J)
Time is measured in seconds (s)
Electrical Power
 Electronics is mostly concerned with small quantities
of power, so the power is often measured in milliwatts
(mW), 1mW = 0.001W.
 For example an LED uses about 40mW and a bleeper
uses about 100mW, even a lamp such as a torch bulb
only uses about 1W.
 The typical power used in mains electrical circuits is
much larger, so this power may be measured in
kilowatts (kW), 1kW = 1000W. For example a typical
mains lamp uses 60W and a kettle uses about 3kW.
Electrical Power
Besides this basic equation for power:
P = I*V
remember we also have Ohm’s Law:
V = I*R .
Challenge: Based upon the two
equations, how is power related to
resistance?
Power
Definition
Power is the rate of using or
supplying energy
Variable
P
Equation
Power = Energy
time
unit
Power is measured in watts (W)
Energy is measured in joules (J)
Time is measured in seconds (s)
Depends
on
Variable
Unit
Ω = Ohm
ELECTRICAL CIRCUITS
S.MORRIS 2006
More free powerpoints at www.worldofteaching.com
Activity Sheet should include your name, date, and the following discovery information
as well as you data table and conclusion. Put in your Mission note book under the
Electronics Tab.
Discovery Activity: Open and Closed Circuits
Purpose: Evaluate and create an open and a closed circuit.
Materials: Mini light bulb, connecting wire, battery
Prediction: Make a prediction of what an open and a closed circuit would be.
Procedure:
1. Read all of the directions. Create a data table to record your results.
Include draws and explanations.
2. Manipulate the materials in many different ways to light the light bulb. Be
sure to draw and explain each trial on your data table.
Conclusion: Review and analyze your data collected from the discovery
activity. Write a conclusion, What is an open and closed circuit.
Would This Work?
Would This Work?
Would This Work?
The Central Concept: Closed
Circuit
circuit diagram
Scientists usually draw electric circuits using symbols;
cell
lamp
switch
wires
Simple Circuits Series circuit
 All in a row
 1 path for electricity
 1 light goes out and the
circuit is broken
 Parallel circuit
 Many paths for electricity
 1 light goes out and the
others stay on
Series and Parallel Circuit
Activity
 Create an Activity Sheet for the following activity.
 Purpose: Describe what happens to the current in a
series as more resistors are added to the circuit.
 Prediction: Predict what will happen to the current in
a series as more resistors are added.
 Procedure: Read all of the directions and create a data
table to organize the information. Include drawings in
your table.
 Materials: 6 V battery, 3 light bulbs (Christmas lights
will work), 6 connector wires
Part 1 Series Circuit
 1. Connect one bulb to the battery creating a closed
circuit. Record the relative brightness and draw the
circuit.
 2. Repeat step 1 and add a second light. Record and
draw.
 3. Repeat step 2 and add a third light. Record and draw.
 4. Remove the middle light. What happened?
 5. Conclusion: Write a statement which decribes what
happens to the current in a series circuit as you add
more resistors (lights)?
1
2
PARALLEL CIRCUIT
 Place two bulbs in parallel. What do
you notice about the brightness of the
bulbs?
 Add a third light bulb in the circuit.
What do you notice about the
brightness of the bulbs?
 Remove the middle bulb from the
circuit. What happened?
The CrickSAT Mission
 Reflection: Write a reflection paragraph that includes
your understanding of the following questions.
 What connections can you make between Ohm’s Law
and The CrickSAT Project? (purpose, importance,???)