"Shadow"

A shadow is formed when light is partially or completely being blocked by an object.
It is an area of darkness that is formed on a surface.
Do you know that shadows will vary in size depending on the size of the light source, distance between the light source and the object and the distance between the screen and the object.

The shorter the distance between the light source and the object, the bigger is the shadow formed.

The longer the distance between the light source and the object, the smaller is the shadow formed.

When the Sun is low, long shadows are formed while short shadows are formed when the Sun is high.

Heat Energy

Heat is a form of energy. We use it for a lot of things, like warming our homes and cooking our food.

Heat energy moves in three ways:

Conduction
Convection
Radiation

Conduction occurs when energy is passed directly from one item to another. If you stirred a pan of soup on the stove with a metal spoon, the spoon will heat up. The heat is being conducted from the hot area of the soup to the colder area of spoon.

Metals are excellent conductors of heat energy. Wood or plastics are not. These "bad" conductors are called insulators. That's why a pan is usually made of metal while the handle is made of a strong plastic.

Convection is the movement of gases or liquids from a cooler spot to a warmer spot. If a soup pan is made of glass, we could see the movement of convection currents in the pan. The warmer soup moves up from the heated area at the bottom of the pan to the top where it is cooler. The cooler soup then moves to take the warmer soup's place. The movement is in a circular pattern within the pan.


The wind we feel outside is often the result of convection currents. You can understand this by the winds you feel near an ocean. Warm air is lighter than cold air and so it rises. During the daytime, cool air over water moves to replace the air rising up as the land warms the air over it. During the nighttime, the directions change -- the surface of the water is sometimes warmer and the land is cooler.

Radiation is the final form of movement of heat energy. The sun's light and heat cannot reach us by conduction or convection because space is almost completely empty. There is nothing to transfer the energy from the sun to the earth.

The sun's rays travel in straight lines called heat rays. When it moves that way, it is called radiation.

When sunlight hits the earth, its radiation is absorbed or reflected. Darker surfaces absorb more of the radiation and lighter surfaces reflect the radiation. So you would be cooler if you wear light or white clothes in the summer.

Energy story

Energy is one of the most fundamental parts of our universe.
We use energy to do work. Energy lights our cities. Energy powers our vehicles, trains, planes and rockets. Energy warms our homes, cooks our food, plays our music, gives us pictures on television. Energy powers machinery in factories and tractors on a farm.

Energy causes things to happen around us. Look out the window. During the day, the sun gives out light and heat energy.Energy from the sun gives us light during the day. It dries our clothes when they're hanging outside on a clothes line. It helps plants grow. Energy stored in plants is eaten by animals, giving them energy. And predator animals eat their prey, which gives the predator animal energy.

Everything we do is connected to energy in one form or another.

Energy is defined as:

"the ability to do work."

When we eat, our bodies transform the energy stored in the food into energy to do work. When we run or walk, we "burn" food energy in our bodies. When we think or read or write, we are also doing work. Many times it's really hard work!

Cars, planes, light bulbs, boats and machinery also transform energy into work.

Work means moving something, lifting something, warming something, lighting something. All these are a few of the various types of work. But where does energy come from?

There are many sources of energy. In The Energy Story, we will look at the energy that makes our world work. Energy is an important part of our daily lives.

Stored and Moving Energy
Energy makes everything happen and can be divided into two types:

Stored energy is called potential energy.
Moving energy is called kinetic energy.

Changing Energy

Sunlight is taken in by the leaves on the corn stalk and transformed through photosynthesis. The plant takes in sunlight and combines it with carbon dioxide from the air and water and minerals from the ground.

The plant grows tall and creates the ears of corn - its seeds. The energy of the sunlight is stored in the leaves and inside the corn kernels. The corn kernels are full of energy stored as sugars and starch. The corn is harvested and is fed to chickens and other animals. The chickens use the stored energy in the corn on the cob to grow and to move. Some energy is stored in the animal in its muscle tissue (protein) and in the fat.

The chicken reaches maturity, a farmer slaughters it and prepares it to be sold. It's transported to the grocery store. Your parents buy the chicken at the supermarket, bring it home and cook it (using energy).

You then eat the chicken's meat and fat and convert that stored energy into energy in your own body. Maybe you ate the chicken at a picnic. Then you went and played baseball. You're using the energy from that chicken to swing the bat, run the bases and throw the ball.

As your body uses the energy from the chicken, you breathe in oxygen and exhale carbon dioxide. That carbon dioxide is then used by other plants to grow.

So, it's a big circle!


Energy can be transformed into another sort of energy. But it cannot be created AND it cannot be destroyed. Energy has always existed in one form or another.

Here are some changes in energy from one form to another.

Stored energy in a flashlight's batteries becomes light energy when the flashlight is turned on.

Food is stored energy. It is stored as a chemical with potential energy. When your body uses that stored energy to do work, it becomes kinetic energy.

If you overeat, the energy in food is not "burned" but is stored as potential energy in fat cells.

The Muscular System

Muscles are bundles of cells and fibers.
Muscles work in a very simple way. All they do is tighten up--that is, contract--and relax.
You have two sets of muscles attached to many of your bones which allow them to move.
There are 630 active muscles in your body and they act in groups.
Muscles can only pull. They never push.
Muscle contracts to move bones and body parts...

The Skeletal System

Information

Our Skeletal System is made up of bones and joints that works together with our Muscular System to enable our body to move. Our Skeleton is made up of many bones.(Can you guess how many bones are there in our body?) There are 206 bones in our body. (Did u get it right?) ~Questions~ ^_^

1.) What does the skeleton do??? The answer is: It supports our body and gives us our shape. Without the skeleton, we will lose our shape and we will lay flat on the ground. It also protects our delicate organs in our body.

2.) Do you know which are the organs that are protected by our skull and ribcage??? The answer is: Our skull protects our brain and eyes while our ribcage protects our heart and lungs.

The Human Respiratory System

Respiration is a process in which living things take in oxygen to break down digested food to produce energy. During respiration, carbon dioixide is given out.

External Respiration

When a breath is taken, air passes in through the nostrils, through the nasal passages, into the pharynx, through the larynx, down the trachea, into one of the main bronchi, then into smaller broncial tubules, through even smaller broncioles, and into a microscopic air sac called an alveolus. It is here that external respiration occurs. Simply put, it is the exchange of oxygen and carbon dioxide between the air and the blood in the lungs. Blood enters the lungs via the pulomanory arteries. It then proceeds through arterioles and into the alveolar capillaries. Oxygen and carbon dioxide are exchanged between blood and the air. This blood then flows out of the alveolar capillaries, through venuoles, and back to the heart via the pulmanory veins.

Internal Respiration

The body tissues need the oxygen and have to get rid of the carbon dioxide, so the blood carried throughout the body exchanges oxygen and carbon dioxide with the body's tissues. Internal respirtaion is basically the exchange of gasses between the blood in the capillaries and the body's cells

Science Factfile

BREATH IN -- your body gets oxygen from the air. Rib muscles contract to pull ribs up and out. The DIAPHRAGM muscle contracts to pull down the lungs. Tissue expands to suck in air.
BREATH OUT -- you get rid of other gases that your body does not need. Rib muscles relax. The Diaphragm muscle relaxes. Tissue returns to resting position and forces air out.

Our Digestive System and How It Works

The digestive system is a series of hollow organs joined in a long, twisting tube from the mouth to the anus Inside this tube is a lining called the mucosa. In the mouth, stomach, and small intestine, the mucosa contains tiny glands that produce juices to help digest food.

Why is digestion important?

When we eat such things as bread, meat, and vegetables, they are not in a form that the body can use as nourishment. Our food and drink must be changed into smaller molecules of nutrients before they can be absorbed into the blood and carried to cells throughout the body. Digestion is the process by which food and drink are broken down into their smallest parts so that the body can use them to build and nourish cells and to provide energy.

How is food digested?

Digestion involves the mixing of food, its movement through the digestive tract, and the chemical breakdown of the large molecules of food into smaller molecules. Digestion begins in the mouth, when we chew and swallow, and is completed in the small intestine. The chemical process varies somewhat for different kinds of food.

Movement of Food Through the System

The large, hollow organs of the digestive system contain muscle that enables their walls to move. The movement of organ walls can propel food and liquid and also can mix the contents within each organ. Typical movement of the esophagus, stomach, and intestine is called peristalsis. The action of peristalsis looks like an ocean wave moving through the muscle. The muscle of the organ produces a narrowing and then propels the narrowed portion slowly down the length of the organ.

The first major muscle movement occurs when food or liquid is swallowed. Although we are able to start swallowing by choice, once the swallow begins, it becomes involuntary and proceeds under the control of the nerves.

The esophagus is the organ into which the swallowed food is pushed. It connects the throat above with the stomach below. At the junction of the esophagus and stomach, there is a ringlike valve closing the passage between the two organs. However, as the food approaches the closed ring, the surrounding muscles relax and allow the food to pass.

The food then enters the stomach, which has three mechanical tasks to do. First, the stomach must store the swallowed food and liquid. This requires the muscle of the upper part of the stomach to relax and accept large volumes of swallowed material. The second job is to mix up the food, liquid, and digestive juice produced by the stomach. The lower part of the stomach mixes these materials by its muscle action. The third task of the stomach is to empty its contents slowly into the small intestine.

Several factors affect emptying of the stomach, including the nature of the food (mainly its fat and protein content) and the degree of muscle action of the emptying stomach and the next organ to receive the contents (the small intestine). As the food is digested in the small intestine and dissolved into the juices from the pancreas, liver, and intestine, the contents of the intestine are mixed and pushed forward to allow further digestion.

Finally, all of the digested nutrients are absorbed through the intestinal walls. The waste products of this process include undigested parts of the food, known as fiber, and older cells that have been shed from the mucosa.

These materials are propelled into the colon, where they remain, usually for a day or two, until the feces are expelled by a bowel movement.

Science Factfile

When you eat, your body digests the food so your cells can use it to make energy.
Acids and enzymes eat away at the surface of food to break it down.
The small intestine is where food is broken down into molecules tiny enough for the body cells to use.
In the villi are tiny tubes that carry blood called VESSELS. Food molecules are taken into these blood vessels. Once the food is in the blood, it can travel all over the body.