Biology 101: Learning How to Use a Microscope

"The child should never be required to learn the name of anything...but the name should be used so often and so naturally in his presence that he will learn it without being conscious of the process."

-Anna Botsford Comstock, Handbook of Nature Study, p.11.

In order to study microorganisms,  students must first learn how to use a microscope properly. To do this, your student needs to learn the proper vocabulary associated with the microscope. I was most impressed when I was first reading both Charlotte Mason's and Anna Comstock's works how they treated the task of memorizing these types of terms. They suggest that you leave a drawing of the object with the terms labeled on it up in the school area and that, combined with the teacher's proper use of the terms, will lead to the student naturally learning and using the appropriate terms without any special attention paid to the memorization process itself. This was very useful for me because I happen to be that kind of learner myself, having huge difficulty with memorizing lists of things, but not nearly as much trouble memorizing in context.

I have noticed the same is true for many students, even those who find memorizing lists of facts rather easy. When I  taught a group of students biology several years ago, I gave all my students an unannounced end of the year final. I found that a few of the students who excelled on the chapter tests really bombed the final and a few who had only average grades on the chapter tests, received higher marks on the final. After talking to the students,  it seems that the answer was that the students that memorized for the chapter tests used their short term memory, and this information was dumped when the task of memorizing for the next test came along. The students that learned by doing and immersing themselves in the unit only received average grades because they had only been learning about and using the terms for a short two weeks, and hadn't yet completely mastered them yet. By the end of the year, however, they had used, applied and built off of what they had been learning all year and did really well on the cumulative test.

If your student, however, prefers the memorization method, you can practice this with the terms written on Post-it notes and have them put the terms on the correct area of the microscope. Make sure you read through the manual that comes with your microscope to learn the specifics of your instrument.Whatever method you use, make sure you, as the teacher, know and use the correct terms.

To begin your microscope studies, have your student plug in and adjust the brightness of the illumination intensity, and then place the chosen specimen on the mechanical stage and secure it. Make sure that the mechanical stage is farthest position from the objective so that the objective does not touch the specimen slide. Now adjust the x and y stage movement with the knobs so that the specimen is in the center of the viewing area.

Begin with the lowest magnification setting. In our case it was 10x. Next, using the course focus knob, raise the mechanical stage (or lower the objective, if that is how your microscope works) until the objective is close, but not touching the specimen slide. If the student starts with the objective as far from the specimen as he can, the student could accidentally hit the objective against the slide as he goes too close and possibly scratching the lens as well as ruining the specimen or slide while trying to focus the image.

Now your student can focus the image using the coarse focus knob, moving the objective and the mechanical stage farther from each other until the specimen is in focus. Once the specimen is in focus, he can use the fine focus knob to get a sharp image.

Your student can follow the same procedure for the various objectives your microscope may have.

This is the most basic outline of microscope use. Your microscope may have additional features that will need adjustment such as the diopter eyepiece, the iris aperture or the installation of glass filters. You can refer to the manual that came with your microscope to see how to adjust your microscope for these features.

What are some good things to look at initially? 

Starting with a piece of newspaper or a dollar bill can be interesting because it quickly shows the student not only the amount of magnification but also that the images are upside-down and backwards. The student can see that if he moves the paper to the left, the image moves to the right. When he moves the image toward him, the image moves away. Practice with a specimen that is easy to tell this with will make it easier for your student when he gets to specimens for which this fact seems less obvious.

The second specimen I like my students to look at are threads. If you use small pieces of different colored thread, you can show your student how depth of field can affect the image. Have your student put a drop of water on a blank slide sitting on the table. Using tweezers have him place down the first thread. 

Next have him place the second thread on the slide in the same manner, but this time have him place it perpendicular across the first thread so that it makes a cross or X. 

Now have him place the third thread so that it crosses the middle of the X, making a small sunburst type pattern. Now have him place a cover slip over the threads. 

Teach him how to put on a cover slip so as to reduce the possibility of bubbles. To do this carefully place the cover slip so that it is at the edge of the area you want it to go, holding it carefully by its edges. Now, carefully let it fall over the area.

Now have him focus on each thread separately. When one is in focus, the others are out of focus. This will happen when your specimen is not flat.

photo of a "gray" hair, by James using a smart phone camera.

Lastly, I would like to tell you that you can take photographs of the specimens you look at using just a smart phone camera. Just put the camera up to the microscope eyepiece and snap a shot, making sure that the flash has been turned off. As you can see, the photos are not professional quality, but they are nice and can be included in your student's notebook pages. If you print the photos out on regular blank paper, he can make notes or label the parts right on the photo.

Elementary and Middle School Physical Science: Mechanics in Motion: Newton's First Law of Motion {Inertia}

Newton's First Law of Motion is the law of inertia, or the fact that something at rest prefers to stay at rest unless something forces it to move, and something in motion prefers to stay in motion unless something forces it to stop moving.

Inertia Demonstration 1

Stack 5 pennies in a neat stack on a table. Lay another penny on the table near the stack. With a lot of force, slide the penny into the stack.

Only the bottom coin of the stack should have moved. It was forced to move by the moving penny which hit it. The other coins resisted movement because they prefer to stay at rest.

Inertia Demonstration 2

Place a glass of water on a table and place an index card on top of the glass of water. Next, carefully place a stack of 5 pennies on top of the index card. Now, yank the card out.

Did you notice the stack of coins was suspended in midair for a moment? That is inertia.

Now, set up the experiment again, but this time grasp the card with your fingers and slowly  put it away from the glass, keeping the card level as you pull it away. 

This time the coins should have traveled with the card instead of falling into the glass. The coin had a certain amount of inertia sitting at rest. In order to overcome this inertia, a strong enough force would have to be applied. In the first part of this demonstration, friction was not allowed to work long enough to overcome the coin's inertia, so the coin did not move with the card. In the second part of the demonstration, however, friction was allowed to work long enough to overcome the coin's inertia and the coin moved with the card.*

sources and resources:

• Exploring Creation with Chemistry and Physics, Jeannie Fulbright
• Exploring Creation with Physical Science, Jay Wile*

Middle School Biology (grades 5-8) Botany and Human Biology

Weeks 1 and 2: What is Life? An Introduction to Human Anatomy and Physiology


Weeks 3 and 4: Classifying Life

Weeks 5 and 6: Biomes and Food Chains

1. Teach the student about food chains. Include plants, animals, decomposers and scavengers in the chain. Have your student choose a biome such as desert, mountian, rainforest or swamp and write about some of the relationships found in the biome your student is studying.
2. Ask your student to choose an animals from the biome he is studying and find out what type of home the animal makes for itself. 
3. Teach the student about parasites. In this relationship, one organism gets its food from another organism and harms it in the process. A common parasitic relationship is between a flea and a rat. The rate in this relationship is called a host. (Cross-curriculum link: Middle Ages and The Black Death.)
4. Teach about mutualism or symbiosis. In this relationship the two organisms involved help each other. One may provide food and the other may provide shelter.
5. Teach about commensalism. Sometimes two organisms live together but only one of the two benefits and the other is not harmed by the relationship. Have your student look for specific species that have his relationship.
6. Have your student draw a picture and label the cycle of decomposition. Include the living organisms that die, the decomposer that breaks them down into nutrients and the new life that benefits from the nutrients.

Week 7: Botany

Week 8: The Mint Family and Leaves

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Week 9 Parts of a Flower

Week 10: Monocot and Dicots

Week 11: Leaves

Week 12: Stems

Week 13: Fruits

Week 14: Composite Flowers

Week 15:The Human Biology: The Skeletal System

1. The skeleton is a support system that gives the body shape. The human body has 206 bones that protect the organs and act as a system of levers that allow the body to move.
2. Compare bones to exoskeletons.
3. Study the major bones of the body and label the bones on a skeleton sketch. (ribs, ulna, tarsals, patella, phalanges, metatarsals, radius, ilium, maxilla, carpals, ischium, mandible, metacarpals, sternum)
4. Read about joints.
5. Read about ligaments. Ligaments join bones at the joint.  A sprain is a tear in a ligament and take a long time to heal. 
6. Demonstrate the ligament on an uncooked chicken wing or leg.

Week 16: The Muscular System

source: Hands On Muscle Lesson from Adventures in Mommydom

1. There are three types of muscles in the body, skeletal, cardiac and smooth. Skeletal muscle, also called striated muscle, covers the skeleton and makes up a large body weight. Cardiac muscle is found in the heart. Smooth muscles make up the stomach, intestines, blood vessels and diaphragm.
2. Read about how skeletal muscles move a limb. Draw a diagram in your science  journal.
3. How does temperature affect the movement of muscles?

Weeks 17 and 18: Energy and Life

1. Learn about producers, consumers and decomposers and the cycle of life.
2. Learn about how organisms get energy from their food.
3. Learn about combustion in living organisms.
4. Learn about the role of carbohydrates in organisms.
5. Learn about how the body uses calories and metabolic rates in mammals.

Weeks 19 and 20: Health and Nutrition

1. Discuss the role of good nutrition in the health of the human body.
2. Research a topic related to nutrition and write a report or present your findings in a creative format.
3. Complete a nutritional analysis of one day's meals. Analyze the calories, fat, protein, and the minerals and vitamins, calories, protein and carbohydrates. How does it compare to the recommended daily diet of the food pyramid?
4. Discuss the elements of a healthy diet. Refer to the food pyramid that teaches what you should eat each day. Have your student design a menu of foods that would provide you with the appropriate foods for a day. Choose foods that you like, making sure you include each food group.
5. There are three types of exercise. Stretching exercises lengthen muscles and keep them from getting tight. You should stretch before and after vigorous exercise. Teach the student some stretching exercises.
6. Weight lifting is another type of exercise. It develops muscle strength. There are different exercises for the different muscle groups in the body. Resistance of any kind can build muscle. Teach the student some safe resistance exercises.
7. Aerobic exercise is the third type of exercise. It increases the heart and breathing rates, making the heart and lungs stronger.  Brainstorm a list of games, activities and exercise that make your heart beat faster and increase your breathing rate. Make a plan to do these at least three times a week. 
8. Have your student make a circle graph that shows how he spends his day. Have him divide a large circle into 24 pie shaped wedges. Each wedge represents an hour. Have your student make a color code for different activities. For each hour of his day, have him color the wedge to show what he did.

Weeks 21 and 22: The Digestive and Renal Systems

1. Draw and label a diagram of the digestive system.
2. Learn about the pancreas and the effect of sodium bicarbonate on stomach acid.

Week 23: Respiratory System

1. Read about the respiratory system. Review the work of the nose, throat, larynx, trachea, lungs, bronchial tubes, and diaphragm. The respiratory system has the job of providing the body with the oxygen it needs to function. We need oxygen to breathe, but our blood and all other cells need oxygen as well. Respiration includes inspiration or inhalation and expiration.
2. Make a model of the respiratory system.
3. Draw a diagram of the respiratory system. Draw and label arrows to show what happens when we breathe.
4. Learn about blood oxygenation by completing a demonstration showing the capacity of your lungs.
5. Make a working model of the lungs.
6. Discuss respiratory problem and diseases such as tuberculosis, asthma, emphysema, pneumonia, lung cancer, bronchitis and the common cold. Pick one a write a short report about its cause and cure.
7. Conduct an experiment to analyze the chemical make-up of the air we exhale. Pour 100ml of red cabbage indicator in a freezer bag. Make note of the color. Place a drinking straw in the top of the bag and fasten the bag tightly with a rubber band. Take a deep breath and blow into the bag through the straw. Remove the straw and hold the bag shut and swirl the solution gently about ten seconds. Remove the rubber bad and pour the contents of the bag into a plastic cup. Note the change in color. Using an eyedropper, add ammonia (a base) to the solution. Count the number of drops it takes to return the solution to its original color. Discuss the results. What gas did you inhale? How can you tell? What did the ammonia do to the color? Why?

Weeks 24 and 25: The Circulatory System and Life in the Blood

1. The circulatory system includes the heart, the blood, and the blood vessels. Read about this system. The circulatory system supplies food and oxygen to the cells of the body. It also carries carbon dioxide and other wastes away from all parts of the body. The circulatory system also carries substances throughout the body that promotes the body from disease. The heart is the pump that sends the blood coursing rapidly through the network of blood vessels. Make a sketch of how the blood flows through the heart.
2. Read about the elements of blood. Blood is made up of plasma, red blood cells, and platelets. Make a model of the components of blood.
3. What is the difference between the systemic circulatory system and the pulmonary circulatory system? The circulatory system delivers oxygen to all parts of the body. It takes two different routes. One route, the systemic circulation, carries oxygen-rich blood through arteries to all parts of the body. The same system returns the blood, now containing carbon dioxide, through veins to the heart for more oxygen. The other route, the pulmonary circulation, carries blood from the right side of the heart, travels only to the lungs to pick up oxygen, then returns the blood to the left side of the heart where it is sent on to the systemic circulation. Learn about the differences between arteries, veins and capillaries.
4. Learn about blood typing and blood transfusions and complete an activity explaining this.

Week 26: Immune System

1. Vocabulary: Pathogens, bacteria, antibody, vaccinations, immunization, immunity, parasites, antigen, lymph, white blood cells, viruses, fungi, antibiotic, pathology
2. Explain the difference between an active immunity and a passive immunity.
3. Allergies are the result of the immune system reacting to a usually harmless. Allergens stimulate a response such as mucous production.
4. Good personal hygiene can prevent the transmission of diseases. Review good hygiene practices.

Weeks 27 and 28: The Nervous System

1. Read about the brain, spinal cord and nerves.
2. The three major parts of the brain include the cerebrum, the cerebellum and the medulla. Read about the  job of each. The largest part of the brain is called the cerebrum. It appears wrinkled and deeply grooved. The cerebrum controls sight, hearing, thinking, and voluntary muscle movement. The cerebrum is made up of a right and left hemisphere The hemispheres are made up of lobes. The cerebellum is located at the back of the brain and under the cerebrum. The cerebellum controls balance and coordination of movement. The medulla, also known as the brain stem, connects the spinal cord and the cerebrum. The medulla controls involuntary movements, such as the heart, eyes, lungs, stomach and intestines.
3. Draw and label a diagram of a human brain.
4. Some actions are reflexes. The message of pain is sent to the spinal cord and the message is quickly sent back to remove the body from the source of pain.
5. 
   

Week 29: The Integumentary System

1. The skin is the largest organ of the body. It has three layers: the epidermis, the dermis, and the subcutaneous tissue. Read about the make-up of the different layers. Make a model of skin.
2. Draw a diagram of a cross section of skin.
3. One of the jobs of the skin is to regulate the temperature of the body. Learn about the role of perspiration in cooling the body.
4. Another role of the skin is to prevent harmful chemicals and diseases from entering the body. Discuss the importance of keeping the skin clean.
5. Read about how and why pimples are made. What is acme?
6. Read about skin color and how it is determined. Skin color is determined by heredity and exposure to sunlight. The amount of brown pigment, melanin, that the skin cells produce varies.

Solving the Mystery

This week students organized the information they have been getting by analyzing the crime scene map and the lab work they have completed.

 To facilitate their organization of the clues, I took a piece of poster-board and divided it into columns which I headed with the suspects names.

Then we reviewed each of the clues that they could get from the crime scene map...

and the lab work they completed and they evaluated what implications of each clue and put it in the proper column or columns (some clues could implicate more than one person.) 

We then went over each clue and determined whether it was something that definitely implicated that person or whether it indicated that it could be evidence to implicate that person. For the ones that were definite, we outlined them with a marker. We discussed the possibilities of who had committed the crime and talked about whether the suspects had the means (the ability) to commit the crime and what the possible motive (the reason the suspect committed the crime) might be.

We then made a timeline of the events as stated in the statements from the suspects. To make the process easier, we assumed that everything that the suspects said was the truth from their point of view and that the murderer just left out the part where the crime was committed. This helped the students to see the sequence of events and when the suspects had opportunity (whether the suspect had the chance to commit the crime).

I then took a show of hands for each suspect to see which students thought which suspect committed the crime. (There were a few who thought it was multiple people working together.) Based on this, I broke the students up into groups with similar thought and asked them to come up with a story about what happened the night that Mr. Body was killed. (We even had a group that felt that Mr. Body had committed suicide.)

After some time, I had them come back together and each group was allowed to present their case and the rest of the class was allowed to ask questions or ask for facts to back up their story's details. When all the groups were finished, I took another vote and discovered that the stories changed some people's minds.

I did not tell them who I had intended to be the criminal because next semester we are going to take the criminal(s) who the class voted to be the most likely to have committed the crime to trial, and I want them to see through this process how important it is to have solid evidence to convict a criminal. It is a learning process!

As a follow-up to this class, we also had a Mock Trials class. We based the entire Mock Trials class on the information we had gotten from this class. 

CSI: More Labs: Determining pH, Iodine and Vinegar Demonstrations and Fingerprint Analysis

This week we analyzed the cola and the ice cube tray for poison, determined what the white powder found at the crime scene was and examined the fingerprints on the glass.

Class Preparation:

• You will need to have fingerprints for the students to compare with the cup. Use only the thumb and of course make sure that the same person who left the fingerprint on the cup is the same as the one you are using for Mr. Body. Have fingerprints for comparison for the suspects as well.
• You will also need to take with you the cup that was taken from the crime scene in which you developed fingerprints.
• You  need to make up some cabbage juice pH indicator. I found the easiest way is with a blender. You will also need a can of cola and three containers, preferably very small. An eyedropper is very helpful.
• You will need to bring with you water from the ice cube tray (the water you have added 1 Tab. baking soda to 1 cup of water.)
• In addition to the mysterious white powder that was collected from the crime scene, you will need to take with you a package of corn starch, a package of baking soda and some egg carton trays cut into six sections. Small plastic spoons and an eyedropper are very useful as well.

Class Activities:

• Analyze the cola for poison. Obviously, I didn't put actual poison in the cola (and I told the students this) but it does afford us an opportunity to do some pH demonstrations and it mimics similar techniques used to determine what a substance is in actual labs. I put about 1/8 teaspoon of baking soda in the cola to change its pH. For this demonstration, have three small containers available (I used vials). Have your students put some cabbage juice pH indicator in each of them. I used an eyedropper for this. At this time, I talked about what pH was, related it to gardening, and showed them that cola was acidic by the fact that phosphoric acid is one of its ingredients, and that for the purposes of this scenario, our possible "poison" was alkaline. I then talked about how cabbage juice can indicate the pH of a substance, determining whether the substance is acidic or alkaline, by its color change. I then had a student add some of regular cola to one of the vials and the students were thrilled to see the color change despite the fact that the cola was colored brown. They then added some cola from the crime scene and were delighted to see that it changed to a different color. This proved that "poison" was added to the cola! What does this clue tell you?
• Analyze the water in the ice tray for poison. Do this in the same way as you did the cola, using plain water and the water from the ice cube tray (in which you have already added baking soda to.) The colors will be even more dramatic without the cola brown to mute them. Your students will find out that the poison was in the ice, and therefore got into the cola probably from the ice. What does this clue tell you?
• Analyze the mysterious white powder to determine whether it is cornstarch or baking soda. To your six-section containers add cornstarch to the two cells of the first column, and baking soda to the two cells of the second column. Now have your students test the first row by adding three or four drops of iodine to the powders. If the iodine turns black, that means there is the presence of a starch. You can see that it doesn't change color in the baking soda. Now have your students test the second row by adding a few drops of vinegar to the cells. The vinegar will fizz in the presence of baking soda, and will do nothing to the cornstarch but get it wet. Now have your students test the mystery powder. Is it cornstarch or baking soda? What does this clue tell you?
  
  
  

• Compare the fingerprints that have shown up on the cup with those in the case file. You might need to help your students by guiding them to look for loops, whorls and arches. 



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What does it mean that only Mr. Body's fingerprint was found on the glass?

Next week we will be analyzing all of the clues to help us determine what happened to Mr. Body.

CSI: The First Labs: Ink Chromotography, DNA Fingerprinting, Handwriting Analysis, Developing Fingerprints

We did our first labs for our CSI class. This class will need a little prior preparation, but it was well worth it because the kids were very interested and kept to task the entire period.

Preparing for Class:

The chromotography demonstration set-up.

• Prepare chromotography strips for the class. Take the pen you used for the note and another pen and make chromotography strips for them. Instead of a second pen, to make sure the strips are dissimilar, you can use ink from a jar of ink used in pen and ink projects or you can make your own ink by mix together 1/2 tea. red food color and 1/4 tea. green food color. 

from Mystery Science; Part III: Ink Chromotography (If you want to do the experiment yourself)

Make a dot of the ink from the ink used to write the note on one 1-inch x 3 inch rectangle of paper towel. Make a similar dot of the second ink on an identical 1-inch x 3 inch rectangle of paper towel. Label each strip with a pencil. Tape the strips each to a pencil or craft stick. Set these sticks over the rims of two glasses of water so that the water touches the strips and climbs up the strips. When the water moves through the dots, the ink should separate. They should separate in a different manner. If they don't, then choose another type of ink for your second sample. You want them to look noticeably different.

• Prepare the DNA fingerprints. To prepare someone's DNA fingerprint, cells are removed from that individual and the DNA is extracted from those cells, then cut into small pieces with restriction enzymes. Because everyone's DNA is different, restriction enzymes cut everyone's DNA into different sizes and numbers of pieces. By analyzing the DNA pieces, an investigator can distinguish one individual from another. To look at these pieces, the DNA fragments are loaded onto a gel and then are exposed to an electrical field that causes the fragment to travel through the gel. The rate and distance at which fragments can travel through the gel depends on their size.  Eventually the fragments form invisible bands throughout the gel. These DNA bands are then transferred to a nylon membrane. Radioactive DNA probes are added to the membrane, then x-ray film is placed over the radioactive probes on the membranes. When the x-ray film is developed, the radioactive probes have exposed it in places where there is DNA. This film makes a DNA print. As you can see, completing this process in a class lab would be difficult (although not impossible -see below) and so you will need to draw some fictitious DNA fingerprints. On a thin strip of white paper, draw a series of thick, medium and thin lines with gaps of various widths between them. Make two copies of one (one for the perpetrator and one that the lab will give to your CSIs) and different ones for the other suspects.
• Prepare handwriting samples. Have four people, including the person who wrote the note, give a handwriting sample, even if it is just a signature on the statements (see below.)

Class Activities:

• Read and analyze the suspect's statements. I wrote out statements of each of the suspects. They were a little lengthy to put in this post, but if you are interested in doing this scenario, I can send them to you. (NOTE: I HAVE SINCE LOST THESE DURING S HIME RENOVATION PROJECT AND CANNOT SEND TO ANYONE. I AM SURE YOU CAN MAKE UP STATEMENTS THAT WILL FIT. JUST THROW IN A COUOLE OF RED HERRINGS!) The pertinent facts were that a brown pen was found in the kitchen and another in Professor Plum's front pocket. Each of the statements were signed. Analyzing the statements for clues may take a bit of time, so work through it slowly.
  
• Perform chromotography lab on the ink from the brown pens. Your students will now perform the same lab as you did with the two inks, with the ink from the mysterious note. Which ink is it more like once it begins to divide? Can you identify which pen the ink came from. Who does this implicate?
• Identify the DNA fingerprint from the hair in the comb. Explain the process of DNA fingerprinting and then show your students the DNA fingerprint you made that the lab will give to your students. Show them the DNA fingerprints from all the suspects. Have them compare them and match the DNA fingerprint from the lab to the matching one among the suspects. What does this clue tell us?
• Analyze handwriting samples. Have your students compare the handwriting samples to that of the mysterious note. There are twelve basic characteristics your students can look for  when comparing handwriting. They can circle where they see similarities in the samples. Which one has the most comparisons to the note? What does this tell us?
• Line quality: Do the letters flow or are they written with very intent strokes?
• Spacing of words and letters: What is the average space between words and letters.
• Ratio of height width and size of letters: Are the letters consistent in height, width and size?
• Lifting pen: Does the author lift his pen to stop writing a word and start a new word?
• Connecting strokes: How are capital letters connected to the lower case letters?
• Strokes to begin and end: Where does the letter begin and end on a page?
• Unusual letter formation: Are any letter written with unusual slants or angles? Are some letter printed rather than written in cursive?
• Pen pressure: How much pen pressure is applied on upward and downward strokes/
• Slant: Do letters slant to the left or right? You may be able to use a protractor to determine the degree of the slant.
• Baseline habits: Does the author write on the line or does the writing go above or below the line?
• Fancy writing habits: Are there any unusual curls or loops or unique styles?
• Placement of diacritics. How does the author cross the t's or dot the i's?

• Develop the Fingerprints. Hold up the bag from the crime scene with the fingerprints.  Put 3 or 4 drops of Krazy Glue on a small piece of aluminum foil. Place the glue so that it won't directly touch the cup and seal the bag and put it some place safe. Explain that over several hours, the gas from the glue will adhere to the oils of the fingerprints and make the fingerprints appear white and easier to see. Explain that you will have them try to identify the fingerprints the next time you meet.

(Note: You can do your own DNA fingerprinting lab if you can buy Edvotek Kit #109 ($79), electrophoresis apparatus ($199), power supply ($199), automatic micropipet and tips ($179), balance, microwave or hot plate, white light visualization system ($119). Obviously this is out of most home educator's budget for just one science demonstration. I felt I needed to say, however, that it can be done at home, if you are so inclined.)

How to Make Red Cabbage pH Indicator (without stinking up the kitchen!)

Red cabbage makes a great pH indicator, but making it by boiling it on the stove for the juice can make the house smell like, well, cabbage, which for most, is an unpleasant smell.

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There is an easier way, and, surprisingly, it produces more juice than the boiling method.

1. Take about 1/3-1/2 of a small red cabbage and slice it into large shreds.
2. Put the cabbage shreds into a blender.
3. Add about 2 cups of boiling water.
4. Turn on your blender and blend until you have a mush (yes, mush is a scientific term on this blog.)
5. Put a strainer over a bowl. Pour the mush into the strainer, straining out the juice.
6. Now you can  use this red cabbage juice as an indicator. Acids will turn the pigments in the indicator to a reddish color; bases will turn the pigments bluish or yellow-green.
   
   

How to Make Litmus Paper with Red Cabbage Juice

1. Cut strips from plain white paper towels about an inch wide and a couple inches long.
2. Take the paper towel strips and soak them in the cabbage juice for about a minute. Remove them and let them dry on something that won’t stain.
3. Let the paper strips dry and as soon as they are dry your litmus paper is ready to use.