The Scientific Method  
 
Georgia Professional Standards Addressed in this Lesson:  
S7CS4: Students will use tools and instruments for observing, measuring and manipulating equipment and materials in scientific activities.  
S7CS6: Students will communicate scientific ideas and activities clearly.  
 
Science is basically the process of observing things, asking questions about the observation and conducting experiments to find answers to the questions.  
 
Life Science - the study of living things. Life scientists conduct research or experiments that help in finding cures for diseases, conduct research to understand the components of cells, understanding how the living organisms in the environment effect each other as well as the forces or occurrences that impact living organisms.  
 
In order to do the work of scientists, the scientific method has been designed to break the process into stages. The scientific method is often described as a series of steps that is used to answer a question or solve a problem.  
 
There are six steps to the scientific method: 1) Ask a Question 2) Form a Hypothesis 3) Test the Hypothesis (Conduct Experiment) 4) Analyze the Results of the Experiment 5) Draw Conclusions and 6) Communicate the Results.  
 
Ask a Question  
When you observe something you do not fully understand you often ask yourself a question about what may have caused what you observed. Once you ask yourself a question, you must often do more observations while searching for the answer.  
 
Form a Hypothesis  
The hypothesis is a logical explanation for what you have observed. In other words you make a possible explanation to the phenomenon you observed. The hypothesis is usually written in the form of an If…,then statement. Example: If I take a balloon and fill it with air I can poke it with a sharp needle and then it will deflate very fast. This can be easily tested with a blown up balloon and a sewing needle.  
 
Test the Hypothesis  
When you test your hypothesis you are conducting experiments that may help you explain the phenomenon or observation. Many of the experiments scientists use are designed by the scientist working on solving the problem or phenomenon observed. This means that many scientists must be somewhat creative and often think “outside the box” to set up their experiments.  
 
When scientists test their hypothesis, they utilize controlled experiments. A controlled experiment is an experiment that tests only one factor at a time. The one factor being tested is known as the variable. Scientists only test one variable at a time to be more certain that it is the variable causing the effect.  
 
 
 
Analyze the Results  
After the experiments have been completed, the scientist must carefully analyze the results and determine if the results help in solving the problem or answer the hypothesis.  
 
 
 
Draw Conclusions  
The scientist must look at the data gathered from the experiments and draw a conclusion based on the results from the experiment. In other words, does my data support or not support the hypothesis that was formed.  
 
 
Communicate the Results  
This step involves telling others in the scientific field about your experiment and your findings. At this point other scientists may want to see if they can replicate you experiment or maybe modify your experiment to see if they come up with the same conclusion(s).  
 
Sometimes a problem may be tested over and over with scientists getting the same results. When this occurs, we call the explanation of why something occurs in a particular way a theory.  
 
Tools that Scientists Use  
Many of the tools scientists work with are often new and have been developed to work on specific research experiments. We often call this technology. Technology is the use of knowledge, tools, and materials to solve problems and accomplish tasks.  
 
One of the most common pieces of equipment for scientists to use is a microscope. Scientists use microscopes to see things in more or greater detail. There are two main types of microscopes scientists use: 1) Compound Light microscope and 2) Electron microscope.  
 
Compound Light Microscope – has three main parts (a tube with lenses, a stage and a light source). Specimens are often viewed with compound light microscopes that have been dyed (stained) in order to see the object better. The specimen or object is placed on the stage in order for the light to pass through it and as the image passes through the lenses, it becomes magnified.  
 
Electron Microscope – this is where tiny particles of matter (called electrons) are passed through (with a transmission electron microscope) or bounced off of the specimen (scanning electron microscope). A flat image is produced with the transmission electron microscope and a three dimensional image is produced with a scanning electron microscope. All organisms viewed with the electron microscopes must be dead because the electrons passing through them or bombarding them will cause death or mutations.  
 
Other Tools  
X Rays allow us to detect internal structures (broken bones) or living organisms.  
 
CT (Computed Tomography) Scans and MRI (Magnetic Resonance Imaging) these tools provide clearer images of internal tissues than X rays. These tools create images that experts can interpret.  
 
Computers are very prevalent in science. Computers now allow scientists to model different problems and modify the influences to see what results occur. You are probably familiar with computer generated weather forecasts if you watch the weather on nightly news. Computers are also one of the fastest methods for communicating, writing research articles for journals, calculating numerical data, and organize information to name a few uses.  
 
 
Systems of Measurement  
Scientists are constantly measuring things (temperature, mass, velocity, volume, and length to mention several). Scientists use the metric system to take measurements. For length we use the meter as the standard, for mass we use the gram as the standard, and for temperature we use Celsius, and for volumes of solids we use cubic units and for liquid volume we use liters.  
 
We must realize that each major unit has subunits based on the value of 10. Look at the following prefixes and know what they represent: (we will be using the prefixes with the standard length unit in this example)  
 
Kilo = 1,000 Kilometer = 1,000 meters  
Hecto = 100 Hectometer = 100 meters  
Deci = 1/10th Decimeter = 1/10th of a meter  
Centi = 1/100th Centimeter = 1/100th of a meter  
Milli = 1/1,000th Millimeter = 1/ 1,000th of a meter  
 
Most of these prefixes are also used with other measuring units. Example: Many times scientists need a liquid in small amounts so we measure it in milliliters (1/1,000th of a liter). We will practice with these in our homework/class work worksheets throughout the year. Remember to use the best suited unit for your measurements. We would not measure the length of a soccer field in millimeters normally, we would want it in meters. Small objects like algae or bacteria would not be measured with meters, but some subunit of meters like micrometers (1/100,000th of a meter).  
 
Measuring Area - area is the measurement of how much surface something has. We measure area with the following formula:  
Area = Length X Width or (L)(W)  
Notice that this will give us SQUARE UNITS. Example: If we have a rectangle that measures 3 meters in length and 2 meters in width, we can calculate the area of the rectangle by using our formula Area (A) = (L)(W) or (3)(2) which equals 6 SQUARE meters.  
 
Practice: Measure a regular sheet of notebook paper and calculate the square inches in centimeters. Answer: _________________ square centimeters (sq. cm.)  
 
Measuring Volume – volume is the amount of space something occupies or as in the case of a box, the amount of space it contains. We can calculate volume by using the formula as follows:  
Volume (V) = Length (L) X Width (W) X Height (H)  
Notice this will require a cubic unit on the answer. Example: If I have a plastic container that measures 4 meters wide, 6 meters in length and 2 meters in height, we can calculate the volume of water the container will hold.  
V = 4 meters X 6 meters X 2 meters which equals 48 Cubic meters  
 
Scientists often have specific tools to measure liquids. The most accurate tool is the graduated cylinder. It is a cylinder with marks (often in milliliters) that we will use in lab. When in class you can see one of the graduated cylinders on page 25 of your text book.  
 
Measuring Mass – mass is the amount of matter that makes up an object. The basic unit of mass is the kilogram. When we measure the mass of small items or organisms we may use milligrams, or in the case of our labs we usually measure in grams. The tool used to measure mass is the triple beam balance scale. We will use one of these in lab and you must know how to use it and read the scale.  
 
Measuring Temperature – temperature is the measure of how hot or cold something is. Temperature is really a measure of how fast or slow molecules are moving. The higher the temperature, the faster those molecules are moving. We measure temperature with a thermometer and in degrees Celsius. Celsius is the metric system’s unit of scale, while Fahrenheit is the unit we use in the United States.  
 
You should know that water boils at 212 degrees Fahrenheit, which is 100 degrees Celsius. Normal human body temperature is 98.6 degrees Fahrenheit, which is 37 degrees Celsius. Water freezes at 32 degrees Fahrenheit, which is 0 degrees Celsius.  
 
Safety – during science class this year we must observe safety rules. No horseplay will be allowed in the science room, no eating or drinking should occur. Always follow directions your teacher outlines and discusses. If you do not understand something, ask the teacher instead of “trying” something that could result in an accident.  
 
 
 
SCIENTIFIC METHOD WORKSHEET  
 
The study of living organisms in best known as L_________ S______________.  
 
The s_____________________ m_________________ is often described as a series of steps that is used to answer a question or solve a problem.  
 
The six steps to the scientific method are  
A_____ a Q_____________  
F______ a H______________  
T_________ the H________________  
A_____________ the R______________  
D_____________ C_____________________  
C_____________________ the R____________________  
 
An h__________________ is an “if…….then” statement that scientists use to try and explain an event or phenomenon.  
 
A c____________________ e____________________________ is an experiment in which only one factor is tested for at a time.  
 
The factor that scientists are testing during a controlled experiment is known as the v________________.  
 
After a scientist completes an experiment, the scientist should a______________ the r_____________________.  
 
After all the data from an experiment has been carefully reviewed or analyzed, a good scientist will d_____________ c_______________________.  
 
When a scientist has made all of their conclusions, they should c___________________________ the r____________________ to other scientists as well as others interested in their research.  
 
A t_______________________ is an explanation of why something occurs in a particular way and has been tested many times with the same results.  
 
The use of tools, knowledge, and materials not previously available to scientists is known as t__________________________.  
 
A c______________________ l__________________ m______________________________ is often used to magnify objects. This tool consists of a tube with lenses, a stage, and a light source.  
 
A e_____________________ m__________________________ uses tiny particles called electrons to form a computerized image of an object being looked at.  
 
X R_________ are a form of technology that allows us to form images of internal structures like bones.  
 
Computers are often used in making m_________________ to see what different effects occur when different variables are applied.  
 
The metric unit for measuring length is the m__________________.  
 
The metric unit used for measuring mass is the g_______________________.  
 
Liquid volumes are often measured in l_________________ or small amounts in m_____________________.  
 
C__________________ is the metric unit we use to measure temperature in science.  
 
If we want to get the area of a field that is 20 meters wide and 40 meters long we would multiply the l______________ times w__________________.  
 
What is the area of the scenario in question 20? ____________________ square meters.  
 
If a refrigerator has the inside dimensions of .5 meters deep, 2 meters wide and 4 meters tall, what is the volume? _______________________ cubic meters.  
 
Scientists often utilize a t___________________ beam b___________________ in order to get the mass of an object in their laboratories.  
 
How many centimeters are in one meter? _____________________  
 
How many meters are in one kilometer? ______________________  
 
Which prefix means 1/1,000th? M____________  
 
Ten centimeters make up one d______________________.  
 
Revised from Robert Littlejohn  
Revision credited to Kara Ammons 

Posted by: Jeff Allen

NOTES: Copy and Paste these into a word document if you want to print them! 
 
Most organisms must eat other organisms in order to obtain energy for survival, but we have found some organisms that obtain their energy from hydrogen sulfide. These organisms are bacteria. Other organisms then feed on the bacteria. Not only are these bacteria found in deep ocean trenches and in Movile Cave that was discussed in your reading.  
 
PART 1 NOTES  
Every living thing has cells. Humans are composed of about 80 trillion cells. A cell is a membrane-covered structure that contains all of the materials necessary for life.  
 
Most cells are too small to be seen with the naked eye. Organisms with many cells have cells that carry out special functions. Example: Your nerve cells carry impulses to your brain. These impulses may be signals to walk, laugh, talk or be silent.  
 
All organisms have the ability to sense change in their environment and respond to that change. (Getting more cloths if you are cold, taking a sweater off if you are hot).  
 
Living organisms respond to change.  
 
A change in the organism’s environment that affects the activity of the organism is called a stimulus. (Plural - stimuli).  
 
Stimuli can be chemicals, gravity, darkness, pain, light, sounds, tastes, or anything that causes an organism to respond.  
 
Homeostasis  
 
The maintenance of a stable internal environment is called homeostasis.  
 
Even though an organism’s external environment changes, their internal environment must remain fairly constant. Example: the human body must remain at 37o Celsius. If it falls below this, we could go into hypothermia (hypo – below, thermia – temperature) or if it rises much above we could go into hyperthermia (hyper – above, thermia – temperature). Both of these conditions may result in death.  
 
**The maintenance of a stable internal environment is called homeostasis.  
 
If you are too hot, your body sweats. This is your body’s method to cool itself off and maintain homeostasis. If you are cold, your body shivers. This creates heat from the muscles and raises your body temperature to maintain homeostasis.  
 
Living Things Reproduce  
 
Organisms make other organisms like themselves. They can do this in one of two ways: asexual reproduction, or sexual reproduction.  
In asexual reproduction a parent produces offspring that are identical to the parent. (Hydra producing buds on page 38).  
 
In sexual reproduction, it requires two organisms to serve as parents to produce offspring, which will have traits from both parents. (Bears).  
 
Can you think of other asexual and sexual organisms?  
 
Living Things Have DNA  
 
The cells of all living things contain a special molecule called DNA (deoxyribonucleic acid). DNA provides the instructions to build the proper proteins in the organism. These proteins take part in the organism’s cells activities.  
 
The transmission of the characteristics from one generation to the next is called heredity. What are some traits you received due to heredity?  
 
Living Things Use Energy  
 
All living organisms must have energy in order to carry out daily activities. An organism’s metabolism is the total of all of the chemical activities that it performs.  
 
The cells in your body must transport materials into and out of them in order to remain alive. All of this requires energy and the total energy needs is your metabolism.  
 
Living Things Grow and Develop  
 
All living things, whether they are made up of one cell or many cells, grow during periods of their lives. (Single celled organisms have their cell get larger. Multi-cellular organisms add cells to become larger.)  
 
Organisms also go through different stages of development. Humans go through different stages as we develop. (Embryo, fetus, baby, child, adolescent, young adult, middle aged, senior citizen.) (An oak tree begins as an acorn, seedling, sapling, and then a tree)  
 
 
Review  
 
1. What characteristics of living things does a river have? Is a river alive?  
 
A river has energy (it moves – kinetic energy), and can grow larger (flooding). But it is not alive because it is not made of cells, cannot respond to stimuli, has no DNA, and cannot reproduce.  
 
2. What does a fur coat on a bear have to do with homeostasis?  
 
Homeostasis is the maintenance of a stable internal environment. The fur coat of a bear helps it keep a stable body temperature.  
 
 
3. How is reproduction related to heredity?  
 
Heredity is the passing of characteristics from parents to offspring. When organisms reproduce, offspring inherit copies of their parents DNA.  
 
4. What are some of the stimuli that you respond to in your environment?  
 
 
**Notes - Credited to Kara Ammons 
 

Posted by: Jeff Allen

NOTES: Copy and Paste these into a word document if you want to print them!  
 
Section 1  
Cells are similar to factories in that they must obtain materials form outside the cell membrane and remove material within the cell membrane. Food and liquids must be brought into the cell and wastes must be removes from the cell. All of this exchanging must be carried out across the cell membrane.  
 
Diffusion  
 
Particles are always moving whether they be in the form of a liquid, solid or gas. Particles naturally move from areas that are crowded to areas not as crowded. Stated scientifically we would say particles move from areas of greater concentration to areas of lower concentration. We call this process diffusion. Diffusion can occur across cell membranes or outside of the cell. Diffusion does not require any energy expended on the cell’s part.  
 
Diffusion of Water  
 
All living things require water. Recall that humans cannot survive except for about three days without water. Water is diffused through a cell membrane, but we call this process osmosis. Osmosis is the process by which water disperses from an area of high concentration to an area of low concentration.  
 
If we place a semi-permeable membrane between pure water and food coloring, what would happen?  
 
Semi-permeable membrane  
|  
Pure Water (100%) | Water (80%)  
| Food Coloring (20%)  
|  
 
In this situation we would have pure water “100%” in a higher concentration and it would flow to the area of lesser concentration (80%) until equilibrium were reached.  
 
Osmosis will occur across cell membranes also. This is why a wilted plant will become firm and erect when watered. The water will enter into the plant cell (area of lower concentration).  
 
Moving Small Particles  
 
Many substances can cross the cell membrane by diffusion and osmosis, but some may be too large to pass through the cell membrane. Recall that the cell membrane is a double layer of phospholipids. Embedded within the cell membrane, you will find some proteins that act as passageways into and out of the cell. Objects that are too large to directly pass into and out of the cell must enter or leave by way of these proteins. This can occur by passive or active transport.  
 
Passive Transport  
 
This occurs where the substance or particle entering or leaving the cell is too large to directly pass into or out of the cell. In passive transport, the particles travel from an area of higher concentration to an area of lower concentration by way of the embedded protein. The cell does not use any energy for this to occur.  
 
Active Transport  
 
In active transport, the particles flow in the opposite direction of diffusion. In other words, the embedded proteins transport the particles from lower concentration to areas of higher concentration. This process requires energy expended by the cell. This energy is ATP. An example of active transport could include sugar molecules needing to get inside a cell where the concentration is higher than the outside of the cell.  
 
Summing it up: Diffusion, Active Transport and Passive Transport are good methods to move small particles into and out of the cell.  
 
Moving Large Particles  
 
At times, large particles will need to enter and exit the cell. This can be done in two ways: endocytosis and exocytosis.  
 
Endocytosis – the cell membrane surrounds the large particle and encloses it to form a vesicle. The vesicle is “pinched off” inside the cell to be used. Remember: endo - into  
 
Exocytosis – This is carried out when a large particle must be removed from the cell. In exocytosis, the vesicles are formed at the endoplasmic reticulum or the golgi complex to carry the particles out of the cell. Remember: exo – exit.  
 
Review on your own:  
1). what is diffusion? 2). what is Osmosis? 3) How do cells take in large materials into the cell? 4). How do cells remove large particles from the cell? 5). Explain passive and active transport.  
 
Section 2  
 
Cell Energy  
 
All cells must have food in order to survive. When you feel hungry, your cells are telling you they need something to eat.  
 
Nearly all the energy for all life comes from the sun. Plants and some algae are able to capture this light energy and convert it into food through the process of photosynthesis. If we did not have plants and other producers, there would not be any consumers.  
 
Photosynthesis  
 
As we discussed in class, plants have molecules that are able to capture the energy of sunlight. These special molecules are called pigments. Most people have heard of the term chlorophyll, this is the molecule that can capture the sun’s energy and use the energy in the production of ATP. The chlorophyll is located in structures called chloroplasts. The chlorophyll is responsible for the colors we see in plant leaves/stems in most cases.  
Plants use carbon dioxide + water + sunlight to yield glucose and oxygen.  
The chemical formula will look like this:  
6CO2 + 6H2O + light energy -à C6H12O6 + 6O2 Glucose is a carbohydrate; this is a form of energy the plant can store. If a consumer eats a producer, the consumer can use the glucose as a source to be used for the production of ATP. Notice that photosynthesis also produces oxygen. We need oxygen to carry out our respiration processes.  
 
 
 
Getting Energy From Food  
 
Consumers must eat other organisms (plant or animal) in order to obtain food. This material can be broken down into a form of energy our cells can use. There are basically two methods to this: 1) cellular respiration and 2) fermentation.  
 
Cellular Respiration  
 
When we respire, we breathe. This means we take in a breath of air into our lungs and we exhale the waste gas carbon dioxide. This is respiration, but not cellular respiration. Cellular respiration is occurring at the cellular level. In general terms, our cells are taking the food in the form of glucose and breaking it down into carbon dioxide and water and releasing energy. This energy being released is in the form of heat. Most of this heat is used to maintain homeostasis (37 degrees Celsius). Some of the energy is stored in the form of ATP. The ATP can be used to carry out biological functions of the cell (we will discuss this in detail later). All of this cellular respiration is occurring in the organelle called the mitochondria.  
 
Summarizing: Glucose + Oxygen à Water + Energy (ATP)  
This is the reverse of what? That’s correct, photosynthesis.  
 
Fermentation  
 
This is essentially the partial breakdown of glucose in the absence of oxygen. When you run and your muscles begin to ache, you are experiencing a type of fermentation. The aching is lactic acid building up within your muscles. Another type of fermentation occurs when yeast cells are mixed with flour and water (making dough). The yeast cells will begin to break down the glucose and give off carbon dioxide gas. This is what causes bread dough to rise.  
 
Fermentation is also used to produce alcohol products. Yeast is added to some form of sugar and as the yeast break down the glucose they give off carbon dioxide and produce ethanol. The percent of ethanol being formed is what finally kills the yeast cells. (Example – winemakers press the sugars out of the grapes and the yeast cells will begin to ferment the juice into wine. Once the wine gets to a certain percent alcohol it becomes toxic for the yeast and they die.  
Section 3  
 
Cell Information  
 
The cell goes through a cycle during its life. The cycle begins when a new cell is made and that new cell goes through specific stages or phases and divides to form new cells.  
 
Before cells can divide to produce new cells, they must make copies of their DNA. Recall that DNA is the hereditary information or genetic information that contains all the information to produce proteins. The DNA is in the form of structures called chromosomes. We can recognize the phase that a cell is in during cell division by looking at the chromosomes and where they are located during the division process. We will look at these phases shortly.  
 
Division of Prokaryotic Cells  
 
Recall that bacteria do not have a nucleus and the DNA is in an oval pattern and is not complex. The bacteria also do not have organelles that are enclosed by a membrane. These are the main reasons that bacteria or prokaryotic cell division is simple compared to eukaryotic cells. Essentially the DNA is copied and the bacteria cell divides with each new cell receiving one copy of the DNA. This division process is known as binary fission, of prokaryotic cells.  
 
Division of Eukaryotic Cells  
 
Recall: Eukaryotic cells are much larger than prokaryotic cells and they are more complex. They have a nucleus and organelles that are enclosed within membranes. The nucleus is where the DNA is “housed”.  
 
The number of chromosomes in organisms has nothing to do with the complexity of the organism in eukaryotic cells. Example: Fruit flies have 8 chromosomes, humans have 46, and potatoes have 48. So is a potato more complex than a human? Don’t answer that! (Joke). If the number of chromosomes determined the complexity, the potato would be more complex. Chromosomes are lined up into pairs. Each chromosome in each pair is similar to each other.  
 
 
 
 
General Eukaryotic Cell Division  
 
The eukaryotic cell cycle has three main stages. The first stage involves the cell growing and copying organelles and chromosomes. The duplicated chromosomes are called chromatids. The chromatids are held together in the center by a centromere (disk shaped structure). Imagine two pieces of wire the same length and same diameter laying beside each other. Then picture the wires joined in the center with a disk of glue. This is essentially what the chromatids look like.  
 
The second stage of eukaryotic cell division involves the chromatids separating. When the chromosomes separate, the process is known as mitosis. This separation stage or mitosis ensures the new cells each get a copy of each chromosome.  
 
During the third stage of the cell cycle, the cell divides and two identical cells, called daughter cells, are formed.  
 
Specifics of Eukaryotic Cell Division  
 
Interphase – this is the phase before mitosis begins. During this phase, all of the DNA and organelles are copied and the cell is preparing itself to enter the mitosis phases.  
 
Mitosis Phase 1 called prophase. During prophase, the DNA begins to “twist” together and darken within the cell. (Imagine tiny, thin fibers twisting. These fibers will become thicker, shorter and more visible. This is similar to what the DNA or chromosomes are doing during prophase). The nuclear membrane breaks apart and organelles known as centrioles move to opposite ends of the cell. A “spindle” made of protein fibers is formed between the two centrioles.  
 
Mitosis Phase 2 called metaphase. During metaphase, the chromosomes line up on the spindle of the cell and are located at the equator of the cell.  
 
Mitosis Phase 3 called anaphase. During anaphase the spindle fibers begin to shorten and the chromosomes attached to the spindle begin to move away from the equator with one pair of chromosomes moving toward the poles or to the centriole location.  
 
Mitosis Phase 4 called telophase. During telophase the cell begins to divide into two cells. Close to the equator of the cell, the cell begins to “pinch inward. This area is called the cleavage furrow. This is the location where new cell membranes will be forming for each cell. Now mitosis has completed and we must discuss the last phase of cell division.  
 
The last phase of cell division is called cytokinesis. During cytokinesis, the cytoplasm divides and the new cell membranes completely form and the result is two identical cells called daughter cells. These cells are genetically the same as the original cell that we started with. At this point the new cells are starting their life cycle or cell cycle.  
 
Plant versus Animal Cell Division  
 
Recall: Plant cells have a cell wall and a cell membrane. During telophase in plant cells, instead of a new cell membrane forming at the cleavage furrow, a cell plate is formed. The cell plate will form the cell membrane of the two new plant cells. After this, a cell wall will form between the two membranes to complete cell division of the plant cell.  
 
Notes adapted from Robert Littlejohn and Kara Ammons 

Posted by: Jeff Allen