by: Cindy Moss, Ph.D
Director of STEM Education for Charlotte Mecklenburg Schools

Guest blogger, Cindy Moss, Ph.D, reflects upon her experiences as a judge at the 2011 Discovery Education 3M Young Scientist Challenge final event and shares words of wisdom.

Serving as a judge for the Young Scientists Competition was one of the most energizing experiences of my 29 year career in education. The talent and potential I have witnessed in the past 2 national competitions has given me hope for our future. The opportunity that the 10 Young Scientists finalists have to work with successful STEM innovators from 3M will provide them with the confidence and skills they need to be successful in any endeavor they embrace in the future. And, all students who entered the competition had the experience of crafting an idea that uses math and science, and working to communicate it to others.

I am currently doing consulting work with the Ministry of Education in Thailand and a private educational group in India. China selected 25 of their top secondary math and science teachers and sent them to spend 6 months in our district to learn how we teach them. Other countries recognize that Americans are the best at collaborating and being creative, but American teachers and schools need to provide more opportunities for our students to master those skills. As educators we are under the stress of preparing our students to take high stakes multiple choice tests and many teachers choose not to take the time for competitions. However, the advent of Common Core State Standards provides STEM teachers with the impetus to engage their students in this type of work. As the Director of STEM education for 140,000 students in my district, I am constantly struggling to find the right kind of STEM learning for my students, and funding to provide it. The 3M Young Scientist Competition is exactly that type of experience. It is real-world, relevant, high quality, free and available to all students in 5th-8th grade.

National Science Foundation research has found that 1 real-world problem experience can be the difference between students choosing to take difficult math and science courses or choosing to drop out of the STEM pipeline. The National Inventors Hall of Fame found that more than 80% of the inventors in the Hall of Fame had the idea for their invention by the age of 10. Most of these successful inventors did not have actually produce their invention until they were middle-aged, but had their most creative ideas before they had been handicapped by learning all the things their current world declared impossible. In our district we have conducted research on elementary students who participated in a week of Camp Invention. An outside researcher found that the quality of the inventions from our economically disadvantaged students was as good, if not better than those of their suburban counterparts. We also found that special education, English language learners, and handicapped students were able to experience success in this type of learning. Our research indicates that Charlotte Mecklenburg students participating in creating a new invention had improved test scores in reading, math and science as a result of their experience and were willing to tackle more difficult science and math classes when they reached high school.

In conclusion I encourage you to engage 5th-8th grade students in the 3M Young Scientist competition so that they experience the joy of creating a solution to a problem and communicating their ideas to others. Remember you can't win, if you don't begin.

Introduction:
The "dog days" of summer are pretty much behind us and I have to say, although some days were brutal, I always end up missing summer. One thing I won't miss however is the feeling of getting into a hot car. You know, that intense feeling of heat overcoming you after stepping foot into your car, which had been parked in the sun all day. Experiences like this get me thinking about how the heat gets inside of the car to begin with. More specifically, how heat is transferred and how we can prevent heat transfer.

The Principles
• Conduction
• Convection
• Radiation

The Science
What is conduction and how does it work?
When heat is transferred during conduction the heat moves from an area of high concentration to an area of a lower concentration of heat. Thermal energy moves between two regions due to a temperature gradient. In most cases, one object is in contact with a second object for conduction to occur. A real-life example of this is when you hold an ice cube in your hand. The heat from your hand moves away from your hand (you are losing heat, making it feel cold) and towards the ice cube. This causes the molecules of water in the ice to speed up, and in turn the ice to melt.

What is convection and how does it work?
Convection is a type of heat transfer that takes place in liquids and gases (both called fluids). During the process of convection heat moves, because the fluid itself moves. Most of us have heard at some point in our lives that, "hot air rises." The better example of convection is water boiling. While the metal pan is heated because it is in contact with the stove (conduction), the metal pan heats the water molecules above it differently. Instead the pan does not touch each of the water molecules. These water molecules then begin to rise to the surface and are replaced by water molecules that are not as hot. A good way to think of this idea is to imagine a bag of marbles. As you carry this bag around with you a hole forms in the bag. Soon marbles start to move from the area of high concentration inside of the bag to the area of lower concentration outside of the bag. Each marble in this case represents heat that has been transferred on a fluid particle.

What is radiation and how does it work?
Radiation (often called thermal radiation) is heat that is transferred through electromagnetic radiation (remember the last blog focused on waves- electromagnetic radiation is part of the electromagnetic spectrum). See the last blog for more information about electromagnetic spectrum and how it relates to waves. A perfect example of this appears when you don't wear enough, or any, sunscreen. Sun burn is a direct result of heat transferring from the sun to our skin through radiation.

See this article for a more in depth explanation of hear transfer and conduction, convection and radiation.

Did You Know!?!
See how 3M has developed thermal barriers for use in auto and truck racing here, as well as developments for NASCAR, Heat Stopper, SHIFT, Issue 1, 2000 and Cool Cures to Beat the Heat, Stock Car Racing.

Try This!
Did you happen to see the virtual lab Too Hot To Handle on the Innovation HQ page? Once you visit the page, use the navigation bar on the left to find Virtual Labs and select the Too Hot To Handle Lab. Read the briefing document and experiment with conduction through the virtual lab.

Introduction:

As I write this blog this week I am on vacation at the shore. I love the shore! I have been lying on the beach all day, reading whatever I want, and watching the waves roll onto the shore. As I was admiring the waves earlier today, I was inspired for this blog. What exactly causes the waves in the ocean?

The Principles
• Waves- properties, characteristics and definition
• Types of waves
• What causes ocean waves

The Science

What are Waves?
Waves are pulses of energy that travel through space and/or matter. Now, not all waves are identical, but they do share the same parts, properties, and the general purpose of transmitting energy. The top of the wave is the crest and the bottom is the trough. The distance from a point on one wave to the same point on the next wave is called the wavelength. The number of waves that occur in a given point of time is called the frequency. The distance a wave travels from its rest point is called the amplitude (see Figure 1).

Some waves need matter in order to transmit energy. These waves are called mechanical waves. They rely on the vibrations of the particles of matter in which they travel in order to transfer energy. Sound is an example of this kind of wave. In order for a sound wave to travel there must be matter (a medium) for it to travel through. Most commonly sound will travel through the air that surrounds us (check this out ), but in reality sound can travel through liquids and solids as well. Have you ever seen someone place his or her ear to the ground in order to "hear" someone traveling in the distance? I saw this all the time in old western movies when I watched them with my grandfather.

Another type of wave is an electromagnetic wave. These waves differ from mechanical waves because they can travel through space without any matter being present (called a vacuum). Instead of matter that is vibrating, electromagnetic waves use the vibration of charged particles. Examples of these types of waves are light waves, radio waves, and infrared waves (really anything that can be found on the electromagnetic spectrum). To read more about waves and their parts see this article.

Types of Waves
Mechanical versus electromagnetic is not the only distinction that can be made between different waves, as there are more differences than simply what they travel through. Waves are also classified based on how they travel. There are three basic types; transverse, longitudinal, and surface waves. A transverse wave is a wave in which the particles in the medium travel in a direction that is perpendicular to that of the wave. To clarify, if the wave is moving from left to right then the particles in the wave will move up and down. The second wave type is longitudinal. In this type of wave, the particles of the medium move in a direction that is parallel to that of the wave. This means that if the wave is traveling from left to right then the particles will also travel from left to right. The final type of wave is a surface wave. Here, the particles on the surface of the medium undergo a circular motion as the wave travels.

What Causes Ocean Waves
Well, we know ocean waves are mechanical, transverse waves. They are mechanical because they need a medium (the water) in order to travel. The waves travel parallel to the horizon, but the ocean water (medium) travels up and down, so therefore ocean waves are also transverse. But how are these waves created? They are actually created from winds that blow across the top of the water. "Disturbances" are created as the wind moves across the water and when these disturbances reach the shore we see the waves "break".

Did You Know!?!
Engineers have used waves in all types of technologies in the past (we would still be a wired society if they didn't) and they continue to use waves when they develop new technologies for society. Check out how 3M uses bending wave technology to enable touch screen functionality for a variety of uses in our everyday life. Check out this link to watch a video on how dispersive signal technology works. [note to blogger....see the video, "how dispersive signal technology works" , which seems simple and instructive, at this link:

Try This!

Now Hear This

In this activity students will create a primitive phone system by connecting empty containers together by using different types of materials and communicating through the string.

Materials
• Scissors
• Metric ruler
• Tape
• String
• Yarn
• Dental floss- waxed
• Dental floss- unwaxed
• Thread
• Empty soup cans
• Empty soda cans
• Other empty containers
• 2- 8 oz. plastic cups
• 2- 12 oz. plastic cups

1. Start by taking the two 8 oz. plastic cups and use the scissors to make a small hole in the bottom of each cup.
2. Cut a piece of string, 2m (200 cm) long.
3. Thread one end of the string through the hole in one of the cups and then tie a knot in the string.
4. To hold the string in place, tape the string on each side of the hole.
5. Repeat steps 3 and 4 for the other cup.
6. Work with a partner and extend the cups as far as they will go.
7. Have your partner place the cup to his or her ear.
8. Whisper something into the cup and have your partner try to hear what you whispered.
9. Switch roles with your partner.
10. Try making different types of phone systems using different materials.

Essential Questions
Which materials work best for your device?
Why do you think this is the case?

Using what you have read above, draw a diagram or create a model of the waves you are using in the phone system you just created. Be sure to label the parts of the wave.

Introduction:

I was on the bus the other day on my way home from work and suddenly there was an outbreak of sneezing. Now, I know that sometimes people just sneeze, it is a reflex after all. The interesting part is that the first comment that I heard after the sneezing fit concluded was by a woman who said, "Well, it's that time of year!" This got me to thinking...why is it that it's this time of year for some people and not others? After all, not everyone goes through these allergies. Just in case you wanted to know a little bit more about sneezing, check out this article.

The Principles

• How Allergies Work
• Different Kinds of Allergies: Seasonal or Triggered
• Prevalence of Allergies

The Science

How Do Allergies Work?
The human body comes with its own defense mechanism, it's the immune system. The human immune system does a fantastic job of warding off disease and foreign elements, but as with anything human it isn't perfect. Sometimes it makes mistakes. Allergies originate from what is called a hypersensitive immune system. In basic terms, the immune system identifies an otherwise harmless object that has entered the body through the nose or mouth as a dangerous object. The sneeze reflex kicks in and out the object goes. To read more about how allergies work and the allergic process read this article or watch the video at the bottom of the page (Body Invaders: Allergies and Dust Mites).

Are There Different Kinds of Allergies?
We know people are allergic to different things, but there are really two categories of allergies; seasonal allergies and triggered allergies. The most common thought about allergies and allergic symptoms is that no matter the category of allergy, these symptoms are brought about by a protein.

Seasonal Allergies- this category of allergy is brought about by substances that occur at certain times during the year. While most people believe that allergies are only brought out in the spring, this really isn't the truth. Instead, people experience allergies throughout every season, it is really dependent upon your body's immune system. To read more about seasonal allergies see this article.

Triggered Allergies- this category of allergy is brought about by substances that are in the local environment to a person. For example, cats and dogs make some people sniffle. Another common type of triggered allergy is food allergies (shellfish, peanuts, etc.). To learn more about these types of allergies, read this article or watch this video (Eat Right, Live Right).

How Prevalent are Allergies in People?
It is estimated that approximately 20% of the population of the United States suffers from allergies; that makes allergies the most common chronic illness. For more information on allergies read these related articles.

Did You Know!?!
Check out the Filtrete website by 3M. Filtrete products are designed by 3M engineers to help capture airborne allergens; which include, air cleaning filters, room air purifiers and water filtration products. There are several ideas listed to help reduce common allergies here .

Try This!
Have students use the article from above, "Don't "Fall" for Fall Allergies", and the Helpful Terms to Know section of the Filtrete website to create a public service announcement for their school. The public service announcement can focus on what allergies are or how to prevent allergies. Have students create brochures and presentations to get the message out!

Introduction:

Over the last few years the price of gasoline has risen dramatically. People with various backgrounds have made suggestions on how to control those prices. Added to the debate have been the disasters over the past two years; the Earthquake in Japan this past March (and the nuclear energy issues that resulted) and the oil spill in the Gulf of Mexico around this time last year. These debates have left the public looking for clean, reliable, safe, and efficient alternatives to meet energy demands. Whether you watch the news on television, listen to it on the radio or read about it in the newspaper, alternative energy resources seem to be a popular topic these days, but what exactly are they?

The Principles

• Fossil Fuels
• Common Alternatives Energy Sources (hydroelectric, geothermal, wind, solar, and biofuels)
• New Alternatives

The Science
What are fossil fuels?

The most common fuel used to power our automobiles is through gasoline. Gasoline is made from crude oil (to see how gasoline is made from crude oil, read this article). Crude oil is a type of petroleum. All of these, gasoline, crude oil, and petroleum are referred to as fossil fuels. There are other types of fossil fuels as well, such as coal and natural gas. Fossil fuels provide more than 85% of all the energy used in the United States according to the U.S. Department of Energy (http://www.energy.gov/index.htm). This shows the great demand we have for fossil fuels here in the United States.

How are fossil fuels formed?

Of course we can deduce from the information above that fossil fuels come from the ground, but how did they get there? As the name suggests there is a tie between fossil fuels and fossils themselves. The characteristic that they share is that they are both formed from the remains of once living things. They were formed from prehistoric plants and animals that were alive millions of years ago.

As these plants and animals died they eventually decomposed and became buried under layers of rock and soil. Over thousands of years they decomposed even further into little pieces of organic material. This organic material then was exposed to great amounts of pressure and high temperatures which transformed it into the fossil fuels we use today. To see a more in-depth look at the creation of fossil fuels, read this article.

What are some common alternative energy resources?

Most people are familiar with some forms of alternative energy resources such as hydroelectric, geothermal, wind, solar and biofuels. While these resources have provided clean and safe energy sources, a major criticism has been their efficiency and reliability.

1. Hydroelectric Energy - falling water turns a turbine which then spins a generator which in turn creates electricity (for a deeper look at hydroelectric power see this article.)
2. Geothermal Energy - heat from inside the Earth turns a turbine which then spins a generator which in turn creates electricity (for a deeper look at geothermal power see this article.)
3. Wind Energy - wind turns a turbine which then spins a generator which in turn creates electricity (for a deeper look at wind energy see this article.)
4. Solar Energy - there are really two ways solar energy can be used; 1) solar energy rays can be collected and used to heat objects, or 2) these same rays can be collected by photovoltaic cells and converted into electricity (for a deeper look at solar energy see this article.)
5. Biofuels - these are fuels that are made from biological raw materials; they differ from fossil fuels in that fossil fuels come from organisms that were once alive and biofuels are living things (plants- generally extra/left-over crops); there is still much research going on around this category (for a more in-depth look at biofuels explore the resources on this page.)

What is on the horizon?

There are several "new" alternative energy innovations that have been popping up over the past several years. Click on the links below to get a closer look at each.

1. Pure (human) Energy - humans using their own mechanical energy to create electricity
2. Floating Wind Farms - wind turbines are placed in floating platforms in the ocean
3. Bug Excrement - bugs can excrete crude oil
4. Piezoelectricity - some metals, when hit, can generate electricity
5. Biogas Digestion - converting waste and kitchen garbage to useable energy

Try This!

Have students conduct a home energy audit (an example of what to look for during a home energy audit can be found here). After students have collected the data for their home, have them research ways to "fix" these issues and determine an approximate cost savings if their solutions are completed (see this article for common "fixes").

Use the Drive It Green lesson to investigate fuel efficiency of different cars and green transportation initiatives. After completion of the lesson, have students apply their own innovation and creativity to develop a commercial for the car that they chose.

Did You Know?

3M is working to improve the reliability and efficiency of both solar energy and wind energy technologies. Click on the links below to see how 3M's innovations have revolutionized these industries:

• Thin Film
• Crystalline Silicon
• Concentrated Photovoltaic
• Concentrated Solar

Introduction:

In my last blog I took a closer look at the definition and types of nuclear energy – in light of recent events in Japan. The main cause of the issues in Japan however was the 9.0 earthquake that hit the country. This blog is focused on earthquakes; where and how they occur and how they are measured.

The Principles

• Plate Boundaries
• Fault Types
• Richter Scale
• Mercalli Scale

The Science

Where Do Earthquakes Occur?
According to the theory of Plate Tectonics (To read more about Plate Tectonics see this article.) Earthquakes occur along breaks in the earth's crust where plates of rock interact with each other. These plates can interact in three different ways; they can move apart, they can push together or they can slide past each other.

When plates move apart from each other (called a divergent plate boundary), magma, from the earth's core, comes to the surface of the earth and then cools.

When the plates push together (called a convergent plate boundary), one plate usually pushes another. This plate is said to be subducting and it sinks into the mantle of the earth. Sometimes neither plate is able to subduct, so they push against each other and form mountains.

Finally, plates can simply slide past each other. The place at which this occurs is called a transform boundary. At these boundaries the plates are pushed very tightly and this causes a great deal of tension to occur.

When the plates move around each other friction is created and eventually holds the plates in place. This in turn creates a great deal of pressure and eventually the pressure causes the plates to "snap" out of place. The initial break in the earth that occurs when this happens is called a fault. This is the main source and location of earthquakes.

There are four main types of faults (see a more detailed explanation and video of each here):

• Normal Fault- as the plates move away from each other the hanging wall pushes downward, across the footwall and in turn the footwall pushes up against the hanging wall.
• Reverse Fault- similar to a normal fault, but the hanging wall pushes up and the footwall pushes down
• Thrust Fault- moves the same way as a reverse fault, but instead of the fault being vertical, it is horizontal
• Strike-Slip Fault- the two plates move in opposite directions (horizontally)

How are Earthquakes Measured?
The most common way to measure an earthquake is to use the Richter Scale (to read more about the Richter Scale see this article). The Richter Scale measures the magnitude of an earthquake and focuses on the amount of seismic energy released by an earthquake. This scale ranges from a 2.0 (which is not felt on the surface of the Earth) to 10.0+, which are massive earthquakes.

The second way to measure an Earthquake is using the Mercalli Scale. The Mercalli Scale measures the intensity of an earthquake and they are measured on a scale of one (I) to twelve (XII) using roman numerals. A value of I on the Mercalli Scale has lower intensity than the value of XII; values of XII are usually found around the epicenter of an earthquake.

Did You Know?

Earthquakes not only pose an immediate threat to human health and survival, but there can be lingering effects as well. The destruction that an earthquake causes can leave behind a large degree of ruble and debris. In these types of situations it is important to be able to respond to the clean-up immediately. This rubble can create dust and debris that humans can inhale. In Japan this risk is escalated due to the radioactivity that has been released from the nuclear reactor. In times like these the use of personal protective equipment (PPE) is much needed.

In hazardous situations, various protective solutions may be utilized; when it comes to innovation and invention, there are a lot of interesting factors that go into product development for solutions to help protect people in many scenarios. 3M develops respiratory protection, head protection, hearing protection, eye/face protection and protective coveralls, all forms of PPE, that keep workers and volunteers doing the clean-up and those delivering supplies safe. Learn more here.

Try This!

Have students take the Fact or Fiction: Earthquake Quiz after completing the activity below, Modeling Boundaries.

Modeling Boundaries

Materials:

• Candy Bar (with three layers nougat, carmel and chocolate such as a Milky Way)- this will represent the layers of the earth
• Diagram of the Earth's Layers for students to use
• Plastic Knife

Activity:

Divergent Boundary
1. Unwrap the candy bar.
2. Hold the candy bar with two hands.
3. Gently push up in the middle of the bar to "bend" the bar.
4. DO NOT separate the bar in two halves.
5. Questions for students

• Have students sketch what they see
• Which layer is cracked?
• Which layer of the earth would this be?
• Explain why earthquakes would occur at a divergent boundary.

CONVERGENT BOUNDARY
1. Holding the Milky Way in both hands, return it as close to the original bar as possible (flat, straight).
2. Push in from the ends of the bar to force the plates together.
3. It might work best to put fingers on edges of bar, not on top and bottom.
4. Try to keep the bar in a straight line.
5. The top layer should do one of two things:

• form mountains
• one chocolate layer will subduct under the other one

6. Questions

• Have students draw a sketch of what they see.
• Explain why earthquakes would occur at a convergent boundary.
• Which type of boundary might have deeper earthquakes, divergent or convergent?

TRANSFORM BOUNDARY
1. Again, return Milky Way to 'original position'- as best as possible.
2. With fingers and thumbs on long edges of bar, slide your right hand forward, pull your left hand back.
3. Questions

• Have students draw a sketch of what they see.
• Have students place an "X" along the edges in their drawing where they would expect to see the most earthquakes.
• Are earthquakes at transform boundaries shallow or deep?

Extension: Construct an Emergency Preparedness Plan

Have students read the articles, Predicting Earthquakes, Earthquake Preparedness, and Earthquake Supplies. Have students work in pairs to construct an earthquake emergency plan for their families or the class.

Introduction:

In recent weeks we've all seen the disaster that has been unfolding in Japan. In times like these it's hard for any of us to imagine what it must be like to be there. The situation with the nuclear reactor has sparked all kinds of discussion about nuclear energy here in the United States and whether nuclear energy is a viable solution to our countries increasing energy demands. I have had the opportunity to hear many conversations over the past few weeks about nuclear energy and what it is. Whichever side you find yourself on (pro or con) for nuclear energy I encourage you to learn more about it! For this blog I wanted to provide just a little background knowledge about nuclear energy and radiation.

The Principles

• Nuclear Energy
• Radiation
• Half-Life

The Science

What is nuclear energy?
Nuclear energy is energy that is produced by splitting or combining the nuclei of atoms. This energy can be naturally occurring, like in the sun. The heat and light we receive from the sun is due to the combining of nuclei of atoms (nuclear fusion). Generally, humans create nuclear energy artificially, but normally through the opposite process (nuclear fission).

Unfortunately, we often refer to nuclear energy as atomic energy. The word atomic (meaning atom) causes a misconception to occur. While the atom is certainly involved in creating energy through nuclear processes, it also provides energy through chemical processes as well. We use the term nuclear instead to refer to just the nucleus of an atom; this is where fission and fusion occur. Nuclear fission is when the nucleus of an atom is split, and nuclear fusion is when the nuclei of two atoms are joined; in either case heat is given off to use for energy.

To read more about nuclear energy read these two articles; Nuclear Energy: Basic Principles and Nuclear Energy: How Nuclear Energy is Released.

How do nuclear reactors work?
Nuclear reactors are really nuclear fission reactors. When we see the smoke that is emitted from the cooling towers, some people believe that the "smoke" is radioactive. This is a misconception. To start with, what is seen is actually not smoke at all, but rather steam.

Nuclear fission (as mentioned above) creates heat. In a nuclear power plant this heat is used to boil water, which in turn causes the water to change into steam. The steam is then pumped through a turbine. This turbine then turns a generator which produces electricity. Although there are different reactor types, the process is generally the same. To read more about nuclear reactors see this article.

What is radiation?
The term radiation can elicit a lot of different emotions from people. Some radiation can be helpful. For example, radiation is used to help kill cancer cells or can be used to heat water that turns turbines and produce electricity. Some radiation is harmful, as the radiation that we can receive from the sun; sunburn is the result of the sun's ultraviolet rays.

Radiation can be released in two forms: electromagnetic radiation and particulate radiation. Electromagnetic radiation is when the radiation has no mass and travels as a wave. Particulate radiation on the other hand occurs from the disintegration of an unstable atom. Read more about radiation here.

What separates the helpful and harmful kinds of radiation?
Both forms of radiation, electromagnetic and particulate, can come from one of two types of radiation; either ionizing or non-ionizing. Non-ionizing radiation is relatively low-energy radiation; it does not have enough energy to cause changes to atoms. Types of non-ionizing radiation include microwaves, radio waves, infrared radiations, visible light and lasers (read more about non-ionizing radiation here).

Ionizing radiation on the other hand is extremely high energy. There is so much energy in fact, that when ionizing radiation comes in contact with an atom it causes the atom to change; it can break chemical bonds. This is the type of radiation that is used to treat cancer cells since it can alter DNA molecules. This is also the type of radiation given off by radioactive molecules. There are three main types of ionizing radiation; alpha particles, beta particles and gamma rays (read more about ionizing radiation here).

Alpha particles are low-energy and can be stopped with a piece of paper or your skin. Beta particles are moderate-energy particles and can be stopped or reduced by a layer of clothing or a substance like aluminum. Along with these particles, gamma rays are emitted. These rays (waves) are high-energy and extremely penetrating; a few inches of lead or several feet of concrete are needed to shield these particles away.

What is meant by the term half-life?
Half-life is a term used to describe the life span of radioactive isotopes. Half-life is the amount of time it takes for one-half of a radioactive isotope to decay. For example, if the half-life of a given isotope is two days, after two days have passed, 50% of the original sample size will be present. Then in two more days only half of that (25% of original sample) will be present. Every radioactive element has a different half-life.

Try This!

Half Life
To have students experiment with half-life:

Materials

• Paper plate
• 100 pennies
• Plastic baggie
• Pen/pencil
• Paper (for data table and graph)

Activity
1. Have students construct a data table with two columns. Label one column trial number and the other number of pennies.
2. Have students place the 100 pennies in the plastic baggie.
3. Have students dump the pennies from the plastic baggie onto the paper plate.
4. Students should carefully examine each penny to see if it is heads-up (still radioactive) or heads-down (no longer radioactive).
5. If the penny is heads down students should remove the penny and place it on a separate pile for later.
6. After students have completed removing the heads-down pennies, they should count the number of heads up pennies and record that number on their data table (this is how much radioactivity) left in their sample.
7. Students should then place all of the heads-up pennies back in the plastic baggie and continue the process until they no longer have any pennies left.
8. After they've finished, have students create a graph of their data table (this will show the half-life of their radioactive isotope graphically).

Extension
If your students have experience with finding the slope of a line, have them find the slope of the line in their graph. This would be the numeric value of the half-life.

Social Issues
Have students research nuclear energy and radiation. Ask them to take a stand on the issue. Is nuclear energy the answer to the United States' energy demands, or do the risks outweigh the benefits? After students have conducted their research have them engage in a debate over the issue.

Introduction:

As a kid growing up I lived in a town where baseball was truly king! Kids were raised to eat, sleep and live baseball. This was what began my love affair with the game. Baseball is a beautiful game; the sun, the smells, the control. I think everyone on their Little League team wanted to be the pitcher at some point. You know, the center of all of the action!

One of the first things that intrigued me about baseball was the pitchers. Unfortunately I just didn't possess the skills you need to be a successful pitcher. I learned this at a young age and decided, I was going to be a catcher. Instead of throwing the pitches I was now the one calling the pitches. They say that baseball is a game of inches, and when a pitcher would through a slider or curveball (note that a curveball breaks from 12-6 (up and down) motion and slider breaks at more a 3-9 (sideways) motion, and a batter would be fooled by the pitch, it would drive me nuts. This leads us to the question for this blog: "How do pitchers throw a curveball?" It's important to note here that the actual science behind this is much different than the mechanics needed to throw it; first we will look at the science, and then see how it applies to the mechanics.

The Principles

• Fluids
• Air resistance

The Science

What are fluids?
Often we think of fluids as being liquids. This is simply not true. To a physicist a fluid is any substance that continually flows under a stress. A simpler way to look at this is to say that a fluid is any substance that will spill or float away. If we look at the four main states of matter (solid, liquid, gas and plasma), three of the four fit the definition above. The only one that does not is solid. The reason has to do with the molecules that make up each state. The molecules of a fluid are not tightly packed and are free to slide/move past each other. In a solid however the molecules are tightly packed and locked in place. They are not able to "flow."

Defining a fluid is important because a baseball travels in a fluid – air – and as you will see in the next section, movement through air causes air resistance.

What is air resistance?
Air resistance occurs when an object moves through a fluid (air). This is a frictional force so it opposes motion, slows an object down or changes its direction. Around 1852 a scientist named Gustav Magnus performed some experiments with air resistance. Instead of just looking at how objects travel through air in a straight line, Magnus wanted to see how these objects were affected by air resistance as they were spinning. What he discovered was that a spinning object traveling through a fluid is forced to move sideways. This is an application of the Bernoulli Theorem. As the ball is spinning through the air, the air under the ball is flowing faster than the air on top of the ball. This difference creates less pressure, which then forces the object to move downwards.

Answer to the Question

In order for a pitcher to throw a curveball, there is a series of things they must do in order to get the science to work. It starts with the pitchers grip. On a baseball there are raised seams. These seams provide a place for the pitcher to grip the ball (this increases friction between the pitchers hand and the baseball). The pitcher must hold the baseball between the thumb, index finger and middle finger (on the seam). As the pitcher throws the ball toward the plate, he "pulls down" on the baseball. This generates topspin. This is where the Magnus Effect comes into play. This topspin creates a larger air pressure on the top of the ball than on the bottom. As the pitch moves toward the plate, this pressure difference causes the pitch to drop or curve downward. For a more in-depth explanation read this article.

Try This!

Visit the Exploratorium site, "The Science of Baseball" here. Students can study the scientific aspects of the game as well as try different activities.

While at the site be sure to visit the activity "Thrown for a Curve." In this activity, you will need a Styrofoam ball, and the directions. Have students experiment with the different pitches and record their observations for each pitch and explain why it does what it does.

Introduction:

In just a few days we will be setting our clocks ahead one hour for daylight savings time. This year it takes place on March 13, 2011 (then, come November 6, 2011 we will be setting back our clocks an hour). Did you ever wonder why we do this or how it got started? Did you know that not all of the United States participates?

The Principles

• Daylight and the Seasons
• Energy Conservation

The Science
Daylight and the Seasons

In the last blog post I stated that the tilt of the Earth is 23 ½° and that due to this tilt (and the Earth's orbit around the sun) we experience warmer temperatures in the summer than in the winter. This is true, but we also get an added benefit to the tilt of the Earth and its position relative to the sun; longer hours of daylight. This is due to the more "direct" angle that the sun's rays strike the Earth. This tilt, along with the location of a region on the Earth, plays a role not only in the climate of the region, but the length of daylight hours as well. To learn more about the relationship between the seasons and the amount of daylight the Earth experiences, see this article.

Who doesn't participate in Daylight savings time? Why don't they participate?

In the United States, Hawaii, most of Arizona, America Samoa, Guam, Puerto Rico and the Virgin Islands do not observe daylight savings time. The reason is highlighted above. If we look back at the last blog, we can see that the location of a region on the Earth plays a significant role in not only the climate, but also the hours of daylight. The one common denominator of these areas is their location along a similar line of latitude. The locations are around the equator which generally experiences an equal amount (12 hours) of day and night. Areas that are closer to the poles of the Earth experience a greater fluctuation of day and night during the course of the year. To see how this works, check out the interactive here.

Energy Conservation

The concept of daylight savings time was first introduced by Benjamin Franklin (read more about Franklin's Essay). Daylight savings time actually started around World War I. The main reason for this was to more closely match the daylight hours with the hours that people were actually awake. The thought process behind this was to conserve natural resources and energy. When daylight savings time was first enacted in the United States it was observed from the first Sunday in April through the last Sunday in October. In 2005 the Energy Policy Act was established and mandated that beginning in 2007 and forward daylight savings would be expanded from the second Sunday in March to the first Sunday in November. To see future daylight savings calendar dates click here.

Answer to the Question

Daylight savings was enacted in order to more efficiently use the hours of daylight brought to us during the different seasons of the year. The main reason for switching to daylight savings time is to conserve energy and natural resources. The rationale is that by using the daylight as a means of heating and lighting, we can cut our fuel costs. The research on this is mixed, while in theory it should work, there is a need for increased fuel for cooling in the summer evenings and heating in the spring and autumn mornings.

Try This!

Have students work through the interactive, Seasons (third from the bottom). After students have completed the activity have them create a model of the Earth-Sun system and explain how the position of the Earth in its orbit affects the number of hours of daylight each hemisphere receives at different points of the year. Students should be able to explain how the amount of daylight changes from summer, to autumn, to winter, to fall.

Use the Home Connection: It's Getting Hot in Here lesson to investigate the use of solar energy in the home. After completing the lesson, have students apply their own innovation and creativity to see if they can develop a material that could be used as an insulator.

Have students conduct research on how cost effective switching to daylight savings time really is. After completing their research, have students apply their own creativity and innovation (like Benjamin Franklin did) to help conserve electricity in their community. Below are some guiding questions to get you started:

• How much energy does your (school, home, car, school bus, etc.) use in a given day?
• How can you help alleviate this energy issue in your local community?
• How can you promote awareness of your energy issue to your local community (home, school, city/town)?