Making Butter is all about Physics

Posted by sophicpursuits

The author of “CookWise” and “BakeWise” writes about the science behind various aspects of cooking and/or baking. For some food items, its all about the physics. For biscuits, it is about the steam generation. For butter, it is all about the agitation and breaking of the suspension.

I have recently started looking into the physics of making butter – and while there are great hands-on science activities that relate to making butter – there is not really a good explanation of what is happening on a microscopic level. (Here is a very good making butter hands-on activity from the Scientific American) But even this experiment doesn’t really get down to the basic science of what is happening. One of the Dairy Science pages comes out and says “exactly how churning works is unknown”.

So, while there is no definitive reference for exactly what is happening, here are a couple of aspects of the overall process:

1) Whole milk – whether from goats, cows, sheep or other mammal – is a complex mixture of water, proteins and fats. In addition, the mother is also providing other essential items including vitamins, minerals and enzymes. (You can go to the Milk Composition Website to learn more.)

2) Milk that you purchase in today’s grocery stores have been pasteurized and homogenized. The pasteurization process requires the heating of the milk to kill the “bad” bacteria, i.e. those bacteria that cause illness in humans. Homogenization is a physical process, by which the larger molecules, primarily fats, are broken down to allow them to remain in suspension. If you can purchase milk from a local dairy, you may be able to find non-homogenized milk. Non-homogenized milk will separate into layers, i.e. a cream layer and a milk layer. (This is a physical separation using gravity. A commercial dairy uses a centrifuge to perform this separation and provides a milk with a consistent fat content. It is still a physical process based upon the density of the material.)

3) Milk can be considered a colloidal mixture. A colloidal mixture is a fluid in which “particles” are suspended in a liquid, or dispersed throughout. You can think of milk as being a mixture of water, butter fat particles, protein particles, etc. suspended and floating around in the container. It is essentially, a liquid with very small solid particles floating in suspension. This is a bit different than an emulsion. An emulsion refers to two separate liquids, with droplets of one liquid floating in another liquid, for example oil and vinegar salad dressing.

So, what is happening when we make butter?

First, making butter requires “churning” or mixing of the cream. We have started with a physical separation of the butter fat into the cream layer and now have begun agitating it. As the churning progresses, air is mixed with the cream to form a foam, i.e. air is trapped among the butter fat particles forming a stable suspension. As the churning process continues, the “whipped cream foam” falls, i.e. the foam is no longer stable, because the butter fat particles have now begun to aggregate into larger particles and are no longer able to form the foam lattice. The churning continues until large clumps of butter can be seen and collected using a strainer.

The entire process appears to be based on aggregation of the the butter fat particles by increasing the amount of individual interactions between the particles through physical agitation. It is apparent that the collisions between butter fat particles under these conditions is inelastic, hence the aggregation of the individual butter fat particles.

Hopefully, this brief explanation will allow you and your aspiring kitchen helpers – to play with physics and enjoy the tasty result!

The Holiday’s are Almost Over – Back to Normal?

Posted by sophicpursuits

On Monday, January 8; most of the United States will return to a “normal” work/school week. For us the holidays are over and we must return to that hectic existence we have built for ourselves. Social and sport groups are resuming full swing, and just look at that in box for the email. (It is enough to make your head spin.)

For homeschoolers, we have a bit of a choice. We can return to that hectic existence on a more reasonable pace. We can choose to focus a bit, put a bit more quality into our curriculum and not have to throw ourselves headlong back into the U.S. interstate speed culture.

So, from a science perspective; why not take a bit of time to reflect just how fast science can change our perspective and fundamentally our lives. On January 8, 1642 Galileo Galilei died. On the same date in 1980, John William Mauchly (with Presper Eckert – the co-inventor of the ENIAC – Electron Numerical Integrator and Computer – the first general purpose computer) died. And, in 1997 – Melvin Calvin died, a Nobel Prize winning chemist and discoverer for the Calvin Cycle, carbon fixing in plants.

All three of these individuals radically changed our lives. So, here are some suggestions based on these three individuals:

Make a telescope (There are several internet how to’s – youtube videos, plans and kits available. Because, every home has a different set of materials, I am not posting a particular one as it may not fit your specific resources.)
Visit the ENIAC Museum Online
Learn more about the Calvin Cycle from National Geographic Education

Boston Tea Party

Posted by sophicpursuits

Two hundred and forty years ago on December 16, 1773, there was an event in Boston. It was a protest over taxes and triggered a number of cultural differences between England and what is now the United States. In the US we have a coffee break – not a “Tea Time.”

For many – this time of year is the beginning of a winter break – so how about starting another tradition? Celebrating the Boston Tea Party – but having a Science Tea Party!

Here are some suggestions:

Want to keep everyone around the dinner table a bit longer? How about a Tea Bag that floats in air? (Note this demonstration uses fire – so needs to be done by an adult – but it is really cool!)

Or a diffusion demonstration with a tea bag – or make a supersaturated solution – Southern Sweet Tea.

How about making a dye for paper or fabric? (For the paper you can make a treasure map.)

Finally – you can explore all five senses with this fun activity.

Have fun and be safe!

A gift that continues to enhance a life

Posted by sophicpursuits

As the holiday season is in full swing – many of us are looking for that special something to give. For me it has always been books. I love to read.

Reading enhances many aspects of life – it opens doors, it expands curiosity, it activates the imagination, it stimulates thinking, and it promotes communication. For many of us – reading is second nature – but for some – it is a luxury. For example in a recent interview with David Risher on NPR he tells of an experience in Ecuador where the library was locked and children did not have access to the books. This experience has inspired him to work with tools that are available in developing countries to get books into the hands of children. While it may seem counter intuitive – eReaders and cell phones – seem to be a great solution.

There is a meme going around on Facebook – showing a child sitting on Santa’s lap saying that the toys wanted for Christmas included space travel, rocket ships, jungles, animals, etc. Santa gives him a library card.

As a child we moved all the time (I am from a military family) – one of the first places I went in our new hometown was the library as it opened the doors to the community and that is where the books were. My home is filled with books (my husband made the mistake when we first were married saying he would never question my expenditures on books – not sure he still shares that sentiment as we now have more books than many small town libraries).

So the gift of reading to me is invaluable – reading to children is a way of spreading that gift. Books allow people to explore without every leaving the comfort of their favorite chair. We have gotten away from reading due to the television and video on demand – but reading, at least to me, is much more expanding and thought provoking.

Reading teaches, reading shares life stories, reading opens opportunities, and creates visions.

So – this holiday season – or anytime – give the gift that expands a person’s world – a book.

For you science lovers – here is a link to the podcast from the AAAS describing this year’s science book recommendations for young readers. My particular favorite is Rosie Revere, Engineer.

Milling, Mining and Ore

Posted by sophicpursuits

December 9, 1879, Thomas Edison formed the Edison Ore Milling Company. The innovator had some new technologies for producing iron from iron ore. While Edison’s endeavor was not financially successful, minerals derived from ores are essential for many products. Iron for steel immediately comes to mind. In an age of plastics and nano-materials from carbon, we tend to forget that our iPhones, computers, soda cans and other common everyday items have materials that are mined and obtained from processing ores.

You probably have materials in your home that have been minimally processed. Have a cat? You might have bentonite, a clay material used as a kitty litter. How about in the laundry? Borax a cleaner is mined. Depending on your salt – it can be mined or come from evaporation. Talc is another example.

The National Mining Association has a site that gives you a list of 40 common minerals and their uses.

If you want to have fun with borax – go to the American Chemical Society website and make slime or flubber.

It is December already…..

Posted by sophicpursuits

You are probably in the throws of a busy holiday week – family, food, traditions, football, fun. And – on Monday you will think – I can’t believe that it is December already.

If you are like most people – you try not to decorate for Christmas until after Thanksgiving. If that is the case – then you can do some fun science to help decorate around the house –

Have you thought of a “Chemist” Tree? You can do pretzel and gumdrop molecules. Or do paper chromatography to create beautiful ornaments for the tree.

You can do some crystallization experiments – growing sugar crystals or growing Epsom salt crystals (NOTE: Parental supervision will be required.) You can also make a solution of Epsom salt in water and “paint” on heavy card stock and let it dry – to form crystals on the paper – this is particularly good on red card stock as you make white crystal images. (NOTE: you should not let children get the Epsom salt solution in eyes or drink the solution. Goggles are recommended.)

Have Fun.

One week away – and preparations are under way

Posted by sophicpursuits

Thanksgiving in the United States is just one week away – and in many households the preparations are underway. This week the make ahead dishes are getting started – or at least the lists are being generated and ingredients are being collected. And it is a great time to think about kitchen chemistry. Some thoughts –

1) Why does starch cause sauces and gravies to thicken?

2) Corn starch is a sheer thickening fluid (i.e. as you stir in the water the mixture becomes harder to stir).

3) There are sugar reactions that form jellies and jams.

4) Caramelization

5) Even the science of browning

All are really fun things to experiment with during this time of preparation. The above are linked to some sites that provide the science explanations.

Have fun and be safe in the kitchen.

November 18 Inspiration for Hands-On Science Fun

Posted by sophicpursuits

For most people – if you ask what happened this day in history on November 18 – not much comes to mind. It is not as famous as Veteran’s Day. But, there are events which occurred on this day – that can spur a flurry of fun science activities – particularly in the area of photography. Nov. 18, 1928 – was Mickey Mouse’s debut on the big screen as “Steamboat Willie”. In 1929 on this day – Dr. Vladimir K. Zworykin demonstrated the Kinescope – a forerunner of the video tape machine. And, in 1787, Louis-Jacques Daguerre was born – the namesake for the daguerreotype – an early type of photograph.

So here are some fun hands-on activities to help explore concepts of photography and moving pictures:

* Pinhole Camera – Instructions from Kodak

* Flip Book from Wikihow – also if you do a quick search on flip books – you can find out how to do them online.

* Using lenses and prisms to bend light – here is one with a magnifying glass – you can

* Fiber optic demonstrations -from the University of Rochester

One other “cool” event for this day in history is the discovery by US Navy Capt. Nathaniel B. Palmer – Antartica

Have fun and stay safe with your hands-on activities.

Remembering and honoring

Posted by sophicpursuits

On the eleventh hour, of the eleventh day of the eleventh month – World War I came to an end. This day is celebrated today as Veteran’s day in the United States. A Monday in November is set aside as a federal holiday to allow communities to honor those who have served and those who serve.

As homeschool families, this day provides an opportunity to integrate our various curriculum activities with what is happening in the community. There is an opportunity to explore history, and conduct interviews with individuals who witnessed events first hand. There is an opportunity to participate in community activities such as parades, concerts, flag raising and lowering ceremonies, and visiting cemeteries.

While we think primarily of history, writing, poetry, and literature for activities related to Veteran’s day – there are some science related topics that can be incorporated as well.

Weather influences history – a wind sock (you can find several craft ideas for making a wind sock) may be an excellent way to show a bit of patriotism as well as incorporating how weather may impact world events.

Technology – while it may have been developed for defense – there are a number of peace time applications of various technologies. Infrared detection is a great example. The infrared cameras can see flaws in metals, and help detect with early detection of equipment failures. Medicine and medical treatments have been influenced by events on the battlefield. Even how goods are transported to your local big box store – is the result of solving a problem during the Berlin Airlift.

Science can be reflected in a number of ways as you celebrate this holiday. You can see it right in front of you in the form of medical devices, architecture, and the overall health of some of those participating in the parade. Just take a quick second to recognize it.

But, don’t forget to thank that veteran for his/her service. It is their dedication to our values that allow us to have the freedoms we hold dear.

Fun Activities for November

Posted by sophicpursuits

Now that Halloween has past and we are beginning to look toward the holiday season – there are a number of activities that can be integrated into any curriculum. In the northern hemisphere – fall colors are in full display. In North America – Canada and the US – Thanksgiving is just around the corner. And, the summer season is starting in the southern hemisphere.

So here are some ideas for some fun science!

Natural dyes are great this time of year – as fruits, berries and spices are abound. The Learning Channel has a “how stuff works” activity on natural dyes. There is an integrated science-art lesson plan from the University of Minnesota. And, there is a quick article from Gardening Know How, which will help you to integrate science into everyday life.

While food science is fun any time of year – in the US and Canada – November is a feasting month. Chemistry and physics abound in the kitchen – look for anything written by Shirley Corriher (Cookwise and Bakewise) – she has wonderful descriptions of what is happening during the cooking and baking. Penn State has a list of several food science activities. The American Chemical Society has an activity page for food as well.

So have fun in November – doing great science while playing in the kitchen.

Don’t forget to stay safe while conducting any hands-on activities with children. These activities should be conducted under the supervision of an adult and should be reviewed prior to conducting them. For more safety tips for hands-on activities. Return to http://www.sophicpursuits.com/Educational-Materials.html.