Friday 9 December 2011

Cardiovascular System

The cardiovascular system is responsible for transporting nutrients and removing gaseous waste from the body. This system is comprised of the heart and the circulatory system. Structures of the cardiovascular system include the heart, blood vessels, and blood. The lymphatic system is also closely associated with the cardiovascular system.

Structures of the Cardiovascular System

  • Heart

    The heart is the organ that supplies blood and oxygen to all parts of the body. This amazing muscle produces electrical impulses through a process called cardiac conduction. These impulses cause the heart to contract and then relax, producing what is known as a heart beat. The beating of the heart drives the cardiac cycle which pumps blood to cells and tissues of the body.
  • Blood Vessels

    Blood vessels are intricate networks of hollow tubes that transport blood throughout the entire body. Blood travels from the heart via arteries to smaller arterioles, then to capillaries or sinusoids, to venules, to veins and back to the heart. Through the process of microcirculation, substances such as oxygen, carbon dioxide, nutrients, and wastes are exchanged between the blood and the fluid that surrounds cells.
  • Blood

    The blood delivers nutrients to cells and removes wastes that are produced during cellular processes, such as cellular respiration. The blood is composed of red blood cells, white blood cells, platelets, and plasma.
The lymphatic system works closely with other body systems such as the immune system and the cardiovascular system. Lymphatic structures filter blood removing microorganisms such as bacteria and viruses, as well as cellular debris and waste. Once filtered, the blood is returned to the circulatory system. Lymph fluid, also called interstitial fluid, bathes tissues and helps to deliver nutrients and oxygen to cells.

"Shocking"

"Shocking" science with actor Kevin Pollak.
This is a clip from a show that highlighted some of Ben Franklin’s science experiments. The host is actor/comedian Kevin Pollak. Here we are demonstrating one of Franklin’s favorite gadgets called a Leyden jar. It was invented in 1745 by Pieter van Musschenbroek and it became an important invention for studying electricity.
A Leyden jar is able to store large amounts of static electricity. The more it is charged with static, the stronger the voltage becomes in the jar. In this clip, actor Marc Evan Jackson is really getting shocked by the Leyden jar, and his reaction is quite real. While the charge in this clip was harmless, a large leyden jar can hold enough of a charge to actually kill a person.

Rapid Color Changing Chemistry!

Sometimes it’s hard to tell SCIENCE from MAGIC - and this little demonstration is a great example of that. In this experiment you will watch an almost clear liquid suddenly turn dark blue in a flash. It takes a bit of preparation, and probably a trip to the pharmacy for materials, but we think it’s worth it.





IMPORTANT SAFETY INFORMATION: This experiment should only be done with the help of an adult. Iodine will stain just about anything it touches and it can be hazardous. Hydrogen peroxide can cause eye and skin irritation - safety goggles are needed throughout the experiment. Be sure your helpful adult reads the caution labels on each container.

YOU WILL NEED :
  • 3 clear plastic cups 4 ounces or larger
  • A 1000 mg Vitamin C tablet from the pharmacy (you can also use two 500mg)
  • Tincture of iodine (2%) also from the pharmacy
  • Hydrogen peroxide (3%) yep, also from the pharmacy
  • Liquid laundry starch (see below for alternatives)
  • Safety goggles
  • Measuring spoons
  • Measuring cup
  • An adult helper
WHAT TO DO:

  1. Put on those safety goggles and mash the 1000 mg Vitamin C tablet by placing it into a plastic bag and crushing it with a rolling pin or the back of a large spoon. Get it into as much of a fine powder as possible. Then put all the powder in the first cup and add 2 ounces (60 ml) of warm water. Stir for at least 30 seconds. (The water may be a little cloudy) Let’s call this “LIQUID A”
  2. Now put 1 teaspoon (5 ml) of your LIQUID A into a new cup and add to it: 2 oz (60 ml) of warm water and 1 teaspoon (5 ml) of the iodine. Notice the brown iodine turned clear! Let’s call this “LIQUID B.” By the way, you’re done with LIQUID A - you can put it aside.
  3. In the last cup, mix 2 oz of warm water, 1 Tablespoon (15 ml) of the hydrogen peroxide and 1/2 teaspoon (2.5 ml) of the liquid starch. This is, you guessed it, “LIQUID C”
  4. Okay, that was a lot of preparation, on to the fun part. Gather the friends and family and pour all of LIQUID B into LIQUID C. Then pour them back and fourth between the 2 cups a few times. Place the cup down and observe….be patient....somewhere between a few seconds and a few minutes, the liquid will suddenly turn dark blue!

This is an example of the chemical reaction know as the IODINECLOCK REACTION. It is called a clock reaction because you can change the amount if time it takes for the liquids to turn blue. (see experiments below) The chemistry of the demonstration gets a bit complicated, but basically it is a battle of chemistry between the starch which is trying to turn the iodine blue, and the Vitamin C which is keeping it from turning blue. Eventually the Vitamin C loses and, bam! - you get instant blueness.

Note: If you do not have liquid starch, you can also use 1/2 teaspoon of corn starch or potato starch. The liquids will be more cloudy and the reaction will happen a bit more slowly, but it’s still impressive.
Clean up: Carefully pour all liquids down the drain with plenty of water and wash your hands. Recycle the cups or dispose of them in the trash.

What is science??

The word science comes from the Latin "scientia," meaning knowledge.
How do we define science? According to Webster's New Collegiate Dictionary, the definition of science is "knowledge attained through study or practice," or "knowledge covering general truths of the operation of general laws, esp. as obtained and tested through scientific method [and] concerned with the physical world."
What does that really mean? Science refers to a system of acquiring knowledge. This system uses observation and experimentation to describe and explain natural phenomena. The term science also refers to the organized body of knowledge people have gained using that system. Less formally, the word science often describes any systematic field of study or the knowledge gained from it.
What is the purpose of science? Perhaps the most general description is that the purpose of science is to produce useful models of reality.
Most scientific investigations use some form of the scientific method. You can find out more about the scientific method here.
Science as defined above is sometimes called pure science to differentiate it from applied science, which is the application of research to human needs. Fields of science are commonly classified along two major lines:
   - Natural sciences, the study of the natural world, and
   - Social sciences, the systematic study of human behavior and society.

Science experiment