Category: general science

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Friction for Children: 4 Tricks to Help Children Understand Friction

By Lorie Moffat

If you’re looking for ways to aid in teaching friction for children then keep reading. So your child comes home from school with questions about friction. How can you help your child understand this concept? Without friction life as we know it would not exist. Every surface would be more slippery than ice. You could not walk, run, write, or even feed yourself without friction. Friction for children is as easy as using common examples to guide your explanation.

Friction for children starts with the basics. Friction is a push, pull, or a force which works against the motion of objects that are in contact as they move past each other. When objects are touching their surfaces tend to stick together, like the tiny loops and hooks of Velcro. Heat and sound are also produced by friction. If you rub the palms of your hands together quickly your hands get warm and you can hear the sound that friction creates.

There are three types of friction; sliding friction, rolling friction, and fluid friction. Sliding friction is caused by two objects touching each other that slide past one another. For example, when you push a large wooden crate across a floor you push against sliding friction. The entire surface of the crate that is in contact with the floor slides against the floor, slowing down the motion of the crate. Rolling friction uses wheels. If you move the identical large wooden crate with a wagon then you exert a force against rolling friction. Only the bottom of each wheel is in contact with the floor. Rolling friction is less than sliding friction; it takes less effort to push the crate on the wagon than to push the crate that is directly resting on the floor. When an object is in contact with a fluid, a liquid or a gas this is considered fluid friction. Airplanes and race cars are streamlined to reduce fluid friction. They have smooth, curved surfaces to reduce the friction, called drag, with the air.

When teaching friction for children it’s important to stress how friction can be advantageous. You light a match using friction. As you strike a match, friction creates enough heat to ignite a chemical compound in the match head that then burns the rest of the match head. Automobile brakes work because of friction. As the brake pads rub against the car’s wheels, the car slows down. Shoes designed for some sports have special soles to use friction to your advantage. Baseball shoes and football shoes have cleats to increase friction by sticking to cracks in the ground. A violinist puts rosin on his bow to increase friction between the bow and the violin strings, therefore producing sound.

However, friction can also be disadvantageous. If a door hinge squeaks, the noise is caused by friction. The space shuttle’s nose and wings heat up dramatically as it returns to Earth from orbit. The ceramic tiles on the shuttle’s nose and wings are designed to dissipate this heat caused by friction. The moving parts of a car’s engine rub against each other and can stick together, causing the engine to seize and to stop working. Using oil in a car’s engine protects the parts from friction. Cooked foods tend to stick to pans. Teflon on non-stick cookware reduces friction between the food and the pan, causing the food to slide. Competitive swimmers wear specially designed racing suits to reduce the friction between themselves and the water so that they can swim faster. A bowler wears extremely flat-soled shoes to slide on the lane right before he releases the bowling ball. Silicone aerosols, oils, grease, graphite (the very soft form of carbon in “lead” pencils), and ball bearings are all used to reduce friction.

By using every day examples, you can teach friction for children and help them better understand this concept. The three types of friction, sliding, rolling and fluid, can either be beneficial or detrimental to the motion of objects. Friction between your pen or pencil tip and the paper you write on allows you to write on the paper. Friction between the ground or the floor and your feet allows you to run or walk along these surfaces. Friction between your food and a spoon or fork allows you to eat with these utensils.

Lorie Moffat has 20 years of teaching experience in both public school classroom and science museum settings. Contact her about special summer online tutoring packages.

Source: http://www.homeschool-articles.com/friction-for-children-4-tricks-to-help-children-understand-friction/

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Standard Time

By Jay Ryan at Homeschool-Articles.com

In the modern world, we use “Standard Time” in which the whole world is divided into 24 time zones. As a result, on any day of the year at any latitude, the times of actual sunrise and sunset vary depending on your location within a time zone — the Sun rises and sets earlier in the eastern end of a time zone, and later in the western end of a time zone.

Standard Time and Daylight Savings are conveniences of our modern world, but this whole scheme tampers with the classical practices of astronomical timekeeping. Throughout history, time was measured according to “Sundial Time.” “12 Noon” was simply the time when the Sun reached it’s highest point in the sky, directly above Due South. Each person saw Noon at a unique time for that location. One sundial would point to Noon while a sundial 50 miles away would read differently by a few minutes.

This system worked fine until our current modern period where inventions of the telegraph and the railroad enabled high speed transportation and communication, requiring a common standard reference for telling time. The problem is, with the current system, the Sun no longer reaches its highest point in the sky at 12 Noon.

Nowadays with Standard Time and Daylight Savings, the Sun can reach “High Noon” in the sky as late as 1:30 PM. The modern system of timekeeping plays havoc with the natural order of “Sundial Time.” Thus, timekeeping is now decoupled from God’s natural timekeepers, the Sun and Moon. Perhaps this is one reason why so few people today understand or appreciate Classical Astronomy, since we no longer take our time directly from the Sun. Sundials can be corrected for Standard Time and Daylight Savings, but not many people today know the tricks. So nowadays most sundials are simply lawn decorations, but not useful as timekeepers.

Jay Ryan is the author of Signs and Seasons, an illustrated, Biblically-centered homeschool curriculum for Classical Astronomy. He is also the creator of the Classical Astronomy Update, an email astronomy newseltter especially for Christian homeschoolers.  Visit his website at ClassicalAstronomy.com.

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Your Science Tool-Kit: Evaluating Scientific Messages

By Samantha Burns at Homeschool-Articles.com

On any given day we are presented with any number of scientific messages;  it is important to understand science, so that we might better understand the natural world around us.  But what do we do if the information makes no sense to us?  What should you do if the message gets garbled by the news-reporter and sounds alien?  How do we know the information we are receiving is accurate, and not skewed to suit a corporation with a private agenda?
We use our scientific tools to question and research the information.
Ask yourself:

  1. Where does the information come from?
  2. Are the views of the scientific community portrayed accurately?
  3. Is the scientific community’s confidence in the ideas accurately portrayed?
  4. Is it a controversy misrepresented or blown out of proportion?
  5. Where can you get more information?
  6. How strong is the evidence.

With these tools you can decipher the messages, discern truth from exaggeration, and gain a better insight to the world around you.  This will aid you in every day decisions you make.  From the minor to the most monumental life-changing decisions you make, I guarantee that a better understanding of science and the world around you is only going to benefit you and yours.
Use the following checklist to determine how scientific something is.

How Scientific Is It?

  • Focuses on the natural world.
  • Aims to explain the natural world.
  • Uses testable ideas.
  • Relies on evidence.
  • Involves the scientific community
  • Leads to on-going research.
  • Benefits from Scientific “Behavior”.

Science is not just a subject to play around with in our school endeavors; it is part of our every day lives.  It is crucially important that we give our children the skills and tools necessary to decipher the scientific messages bombarding them on any given day.  In a world where the natural state of things is in such a precarious place, and a society that is increasingly reliant upon technology, science will surely play a key role.

Samantha Burns is a self-taught homeschool teacher to 2 sons, and wife 10 years to a citizen scientist. You can visit her website at www.squidoo.com/chronologicalhistorystudies.