Critical Thinking and Science

Science is the study of the universe and the beginning of that study is in critical thinkingA person who thinks critically asks questions about nature and attempts to find answers.

When a person is thinking critically, he is attempting to explain events, solve problems, or just simply— to understand God’s universe.  Thinking critically does not mean just being critical, but the the ability to probe and examine a subject open-mindedly and from many points of view.  Once we understand the value of these kinds of thought processes, we can incorporate them into our homeschool agenda.

Critical thinking skills are vital.  Those who can employ critical thinking are better problem solvers, better equipped to understand how and why things work, and better at presenting and defending a logical argument not only in science but in nearly every field of study.

It is only natural, then, to teach critical thinking skills in home school, but what kinds of activities teach critical thinking skills?

First, we have to determine just what is this thing we call critical thinking.  There are several processes involved— analysis, synthesis, evaluation, and attempting to answer the question “why?”.  These types of thought processes really can’t be easily separated one from another, but it is helpful to distinguish them for the purposes of instruction.  These four thought processes are considered to be higher order thinking, and when they are used together, they become problem solving methods. 

Lets examine the four thought processes and then discuss problem solving methods in a bit more detail.

  1. During analysis, the thinker will try to break down ideas to determine an underlying pattern.  For example, you can check your student’s compositions to see if there are any consistent mistakes.   Another example would be checking over test answers to find a pattern revealing a weak understanding in a particular area or subject mastery in another.  In reality, these analyses are what a good teacher does with every test or paper.  Similarly, a scientist will look over data to see if she can determine patterns which would explain the data.  Analysis is often the first higher order thought process applied to solve a problem.
  2. Synthesis is another higher order of thought.  When a person uses synthesis, he or she is combining ideas to get a larger idea or concept.  In the case of a major weather event, scientists often attempt to determine if there is a pattern to the weather system which can be predicted based upon signs like temperatures or barometric pressure patterns.  A common example of synthesis is the combination of high strength of steel with the flexibility of thin strands to make a steel cable for a suspension bridge.  When a new idea emerges from a body of current knowledge, synthesis is at work.
  3. Evaluation is the thought process whereby we try to decide whether an explanation is true.  In school, we teach the children to evaluate their own work and they gradually begin to judge the work of others.  Another use of evaluation is deciding if a conclusion is justified, or correct, or true.  When writing up an experiment, the student is asked to write a conclusion: why did the experiment do what it did?  The student may have used analysis and synthesis to reach the conclusion, but at some point the student will have to decide that it is a good and satisfactory explanation. 
  4. Simply trying to answer the question ‘Why?’ is another type of higher order thinking skill.  Involving you children in this activity is a great way to practice higher order thinking.  These are the ‘I wonder” questions which spark a young scientist’s imagination.  Training a child to ask himself these questions is the goal of a good teacher.  A person who is curious about the universe is one who will learn easily.  This skill is really two-fold: first, the asking of the question, then the attempt at an answer.  Both of these can be learned and practiced.

Techniques for Problem Solving

Problem solving is a way we can practice critical thinking.  Two principle ways of problem solving are the scientific method and the engineering method.  The scientific method allows a scientist to determine what factors may be affecting a system.  By eliminating all but one factors, the scientist can then vary that one factor and measure its effect.  Norman Edmund, founder of Edmund Scientific has written a wonderful book which details the many parts of the scientific method.  Really a book about critical thinking, The General Pattern of the Scientific Method is valuable to every student.

The engineering method, like the scientific method, is systematic, but it is usually applied in concrete rather than theoretical situations.  When a person uses the engineering method, she attempts to solve a very specific problem using the materials at hand.

  1. First, she will carefully define the problem in order to understand exactly what she needs to do.  
  2. Then she will brainstorm ideas to determine many possible methods to overcome the problem.  
  3. Next, she will weigh those ideas to determine the best one for the situation.  
  4. Last, she will refine her work. 

Practice, Practice, Practice! 

Now, for some ideas you can use at home to practice critical thinking skills.  A student may be asked to solve a problem like making a lunch which includes all of the major food groups with an assortment of good-tasting foods— and be made up of what is available without a trip to the store.  This may sound simplistic, but is a good way to introduce the engineering method to your students.

Another good exercise is to build a crane of building blocks (or Legos or whatever) capable of lifting a glass of water off the ground.  Your students use the materials on hand to solve a particular given problem.

Problem solving can be done in the imagination, too.  You can present the children with a hypothetical problem— or one they have read about— and get them to brainstorm possible solutions.

Practicing brainstorming is another fun activity for home.  Science, without brainstorming or divergent thinking, would never have progressed to our high level of technology.  Just think of all of the everyday things you use which have been invented by people doing divergent thinking.  Velcro, transitors, tape recorders, airplane wings, and even the screw, are all examples. 

There are many fun ways you can practice brainstorming, but remember the primary rule:  don’t criticize the ideas the children come up with.  The single quickest way to cut off creativity is to be critical, so make no judgements about an idea no matter how far-fetched.  The important thing is the free flow of lots of ideas.  Later, you will analyze the ideas and toss out the ineffective ones, but for the present, you just want ideas and lots of them.

What kinds of things can you brainstorm with your children?  How about these—

  • how could we get across the street without touching the ground?
  • how can we make light with no house current?
  • how can we save energy used for cooking
  • how can we arrange the furniture for convenient homeschooling?  (You would be surprised at the ideas for this one that the children will come up with.)

Teaching Critical Thinking

Critical thinking is easier to teach when you are deliberate about it.  Most curricula do not attempt to teach critical thinking, so it becomes a stretch for the homeschool parents to follow through.  However, the benefits are greatly outweigh the effort required.  Do teach the children to think— after all, the Scirpture tells us that we should seek wisdom above all else.

How to use an activity to teach critical thinking:

  1. First, do something which allows you to collect data, keeping track of weather and temperatures, for example.  
  2. Next, you chart the data.  The making of a chart is helpful to scientists and students enabling them to see relationships more easily.
  3. Then, help your student to analyze the chart for information or patterns.  
  4. Ask your student if the information applies to other situations or studies.   
  5. Have the student write a conclusion or summary of what was learned.  
  6. If your student is curious about the outcome, he may want to do more experiments to find out more information.  At this point, the wise parent will drop out of the action becoming the curious audience.  This student is now becoming a self-directing critical thinker.

Here’s an Example…

Below is a performance chart which shows some of the factors affecting an aircraft’s takeoff.  An airplane accelerates down the runway causing air to flow over the wings at greater and greater speed.  As the air passes over the wings, they generate lift.  The faster the air, the more lift is created.  But speed is only one vital piece of information in determining takeoff performance.  Weather conditions also affect the takeoff.

Aircraft Takeoff Performance

Gross Wt(lbs) Airspeed at 50 ft. Head
to 50′
to 50′
to 50′
to 50′
2300 68 0 865 1525 1040 1910 1255 2480 1565 3855
2300 68 10 615 1170 750 1485 920 1955 1160 3110
2300 68 20 405 850 505 1100 630 1480 810 2425
2000 63 0 630 1095 735 1325 905 1625 1120 2155
2000 63 10 435 820 530 1005 645 1250 810 1685
2000 63 20 275 580 340 730 425 910 595 1255
1700 58 0 435 780 520 920 625 1095 765 1370
1700 58 10 290 570 355 680 430 820 535 1040
1700 58 20 175 385 215 470 270 575 345 745

Look the performance chart above and answer these questions.
1. What is the temperature of a day when the airplane can take off in the shortest distance?

2.  What are the best conditions for take off? The worst?

A normal curriculum will ask these first two questions.  These questions ask the student to read and show understanding of the chart.  This is the type of question normally found on an achievement test.   

Read on for questions requiring more critical thinking!

3.  How does air temperature affect the lift generated by the wings on an aircraft?  Brainstorm lift factors which the temperature of the air might affect.

4.  In a gas, the molecules have more energy and are farther apart when the temperature is warm.  How does this fact relate to the data in the chart? 

5.  What could you do to the design of an airplane to make it takeoff in a short distance?

6.  If you put ice in the wings, it would cool them and the air around them.  Would this reduce the takeoff roll of the airplane? 

7.  Could you reduce the take off roll by putting big fans at the end of the runway and blowing air down the runway towards the plane?

Are you teaching critical thinking in your homeschool?  Leave a comment and let us know how you’re doing it!

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Fossils: Stones and Bones, part 3: Searching for Fossils on the Internet

Use these helpful resources as you study fossils in your homeschool!

Fossil Sites and Collecting Locations
Straight-forward list by state.

Fossils for Kids
Great, creative website with fun things like the X Marks the Spot page, Now and Then (my favorite), and a Shark Teeth collection!

St. Louis Science Center
Nice museum site: fossils, dinosaurs, and many other topics.

The Creation Museum
70,000 square foot museum in Kentucky that brings the pages of the Bible to life!

San Diego Natural History Museum: Finding Fossils
Kids’ site on the who, what, when, where, why of fossils

Fossils, Rocks, and Time
Produced by the US Geological Survey, a very informative site for your older students

Everything Fossils…Fossil Facts and Finds
An educational site that tells you everything you need to know about fossils, including activities, coloring pages, specific dinosaur information, articles, links, and lesson plans

Black Hills Institute of Geological Research, Inc.
“the leader in paleontological excavations and preparation since 1974, BHI has been helping supply museums and collectors the finest in professionally prepared fossils and cast replicas.”

United Kingdom Natural History Museum: Dino Directory
Online guide to 333 dinosaurs, images, and classroom activities with printable data files.

Champlain Sea Fossils
See pictures of sea fossils from Canada.

Collecting Fossils in California
All you need to know if that’s the state you hail from- check it out!
You can purchase fossils from this outfit: specializing in low-cost, quality fossils.

Fossil Lesson Plans from Dinosaur Train!
I couldn’t resist.  I will definitely be using this with my little Dinosaur Train fanatic.

Print Resources:

An Illustrated Guide to Fossil Collecting by Richard Casanova and Ronald P. Ratkevich.  A fundamental book on fossils and fossil collecting, it starts out with a brief history of collecting incuding some of the famous collectors of the past like Mary Anning who was twelve when she found a complete skeleton of Ichthysaurus.  Following a description of fossils and  how they are formed, is a discussion of fossil classification.  Sounds technical but it is written for the real person who collects for his or her own bookshelf.  There is a generic chapter on the history of the Earth, evolutionary, of course, but written from the ecological standpoint.  Chapters on how to collect and display your fossils are included.  Lists of resources with museums, geological surveys, societies and paleontological libraries finish up the book.  The best chapter in number seven.  This is the chapter on fossil collecting localities in North America.  This is definitely the resource you need to find fossils on your vacation trips.  Recommended for all ages.

Dry Bones…and other fossils by Gary Parker.  A Master Books publication, this one is written from a Creationists viewpoint.  It is a dialog between Dr. Gary Parker and his family on a typical fossil hunting trip in Indiana, Dr. Parker covers most of the bases in the creationist story of the Earth from creation to the big flood, explaining fossils and how they are made.  This book also comes in a read-along tape version for your little ones.

The Illustrated Origins Answer Book  by Paul S. Taylor.  A wonderful reference book for older readers, the Answer Book has two parts: a textbook and a reference section.  The text is very concise having good definitions which are not oversimplified on the page the word occurs.  This book is not for young children, but for interested adults and older children who have been wondering about some little problem with scientific creationism, but didn’t know where to look.  There many quotes from scientists, creationists as well as non-creationists, in the reference section.  A handy reference for creationists who may become involved in debates or lively discussions.

Field Guide to North American Fossils by Ida Thompson.  Photographs!  In color!  This field guide claims to be the first all-photographic one published. Written for the field, the guide is valuable to have in your field pack so that you can identify that odd fossil without losing face before your children.  Actually, any age can use this great little guide.  It is, of course, evolutionary and has a description in the first part of the history of the Earth period by period.  There are interesting details of recent research in this discussion, so don’t overlook it just because of the evolutionary bias.  After the photo section is a chapter which uses words to describe the fossils of that type.  The discussions are correlated to the photos.

Roadside Geology Series This series is wonderful for keeping in the car on a trip and reading along as you ride through the countryside.  Most of the major routes through a state are covered in the books and a lot of the minor ones.  Geology is best studied outside and these books help you do that.  They help you figure out what is going on with the Earth as you travel past roadway cuts and outcroppings.  The book for Texas covers the different geographical sections (examples are from Southeast Texas: Upper Gulf coast), the typical landforms (like saltdomes and rivers), the different processes still going on (like longshore drift and hurricanes), and the larger routes (like Interstates 10, 35, and 45)  and US routes (59 and 290) and state routes (36)  The glossary in the back and lots of pictures throughout the text make it simple to understand.  Most states are covered, you can purchase the books at The Geology Store.

Dino-Trekking:  The Ultimate Dinosaur Lover’s Travel Guide   by Kelly Milner Halls.  This is another traveling book, but you’ll use it before you get in the car.  Well-known and not so well-known dinosaur sites are listed and described here.  In the margin are the details like address, admission prices, and facilities available. There are side boxes with interesting notes from the curators of some of the museums and parks. The last section is a description of many dinosaurs plus a few non-dinosaurs which are included.  Useful for dinosaur lovers.

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Fossils: Stones and Bones, part 2

Here are some activities for you to try at home as you study fossils!

1. Make a cast of a footprint.
Find a really nice paw print of a dog, of a cat, or of some other animal. Clear away the leaves and debris from the outer edges of the print. Take a 1-inch wide strip of card stock (an index card works well) about 11-inches long (longer if necessary) and staple it into a circle. Place the card circle so that it surrounds the print like a fence. Dig it into the dirt a little so that it is secure.  Pour plaster which is the consistency of toothpaste into the print and the fence.  Let set and remove.  You should have a cast of the print.  If you do not have a good footprint, make one using your dog, a little dirt, and some water.  Make mud and press your dog’s paw into it.  Allow the print to dry until it is hard enough to keep it’s shape when touched.  Then make the cast as before.

2. Making a plaster copy of a footprint.
After your cast of the animal footprint has become firm, put a thin layer of petroleum jelly all around the inside of the cast.  Put another card stock sleeve around the casting to make a cuplike form.  Pour plaster of paris at a toothpaste consistency into the cup.  Allow to set.  Remove the card stock and separate the layers.  You should now have a plaster copy of the foot print.  You can do this with your little sister’s hand print, too.

3. Dissolving the bone / the first step of replacement.
When a future fossil is replaced by minerals it is done very slowly, a particle at a time so that the structure of the original organism is still preserved by the replacing minerals.  Sometimes even the cells of the plant are able to be seen even though the original cells are long gone.  This is how the trees were petrified in the Petrified Forest.  The water first dissolves the material of the organism, then replaces it with another particle, a mineral.  Some fossils are replaced with beautiful agates and are turned into wonderful specimen you can use as decorations at home.

You can not try replacement, but you can experiment with the first part of the process, the removal of the material of a bone.  Place a chicken bone in a glass of vinegar or of carbonated water.  Each of these liquids are acidic and will dissolve the calcium out of the bone leaving the cartilaginous material which bends easily.  When a tooth is placed in carbonated water, it will dissolve completely.  Ground water filtering through a future fossil may be acidic.  This acid will dissolve the calcium in the organism leaving a spot which may be filled by a mineral also in the water.  A useful tip:  You can increase the calcium content of a stew by adding the bones of the meat along with a tablespoon of vinegar.  You will not taste the difference but the stew will have a considerable amount of calcium in it taken from the bone by the acid.

4. Fossil hunt
You can make up some artificial fossils by putting objects to be excavated into a matrix which is then carved away to reveal the “fossils”.   What you choose to place into the matrix should depend upon the age of the child and whether it is to be eaten during the experiment.

There are several different things you can use as the matrix.  Some people prefer using plaster of Paris because of its rock-like texture, but it is hard and can be difficult to carve.  If you use this matrix be sure to use eye protection.  Parafin can be used and then carved easily with nails and popsicle sticks.  You can simulate different rock layers by using crayons to color the melted wax.  Remember to be careful with the melted wax.  You can even use cake dough and cook some whole pecans into the dough.  Excavating can be done with forks and spoons.  Jello is another matrix you can use for the “fossil” excavation.  If using an edible matrix, be sure to use edible “fossils”.

The best type of fossil hunt you can do, though, is outside hunting real fossils.  If you live in a city, look for building made of limestone, marble, or some other once sedimentary material.  Many building materials have fossils in them.  Marble, though, once sedimentary has been metamorphosed and changed by pressure or temperature.  The fossils within will have been changed, too, but in many cases are still recognizable.  Many libraries have shells embedded in their steps and we walk over them without ever noticing them.

5. Collecting data.
Use a 3×5 Data Card to record notes while collecting fossils.  You may forget where you collected the specimen and you may want to remember a particular location. On a 3×5 card, jot down the following notes:

Name of the fossil (type of creature or plant, if you know it):
Rocks the fossil came from:
Drawing of the position of the fossil in the rock:
Location of collection site: Get out and collect some fossils and try some of these activities!  Stay tuned for part 3 of this post: Internet and Print Resources for the study of fossils.

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