The Properties and Uses of Materials & Human Body Systems

Properties and Uses of Materials

• Materials are made from matter or substances that can be seen, felt, and touched.
  • Examples: Clothes made from fibers, chairs made from wood or plastic.

Investigating Absorbency

• Experiment to determine which paper has the most absorbency.
  1. Lay a piece of paper.
  2. Label the brand.
  3. Pour the sample.
  4. Observe how the brand reacts.
  5. Record your results.
• Questions:
  • Which brand is the best?
  • Are all types of paper the best in absorbency?

Properties of Materials

• A property of a material describes its characteristics.
• Materials have different properties depending on their composition and intended use.
• Examples of properties:
  • Hardness, softness.
  • Opacity, translucence.
  • Lightness.
  • Roughness, smoothness.
  • Shininess, dullness.

Other Properties to Describe Materials

• Transparency: Can the material be easily seen through?

• Absorbency: Can the material absorb liquid?

• Strength: Can the material be broken easily?

• Flexibility: Will the material bend easily without breaking?

• Electrical Conductivity: Will the material allow electricity to pass through it?

• Heat Conductivity: Will the material allow heat to pass through it?

  1. Take different materials.
  2. Have them touch a heat source inside.
  3. Take observations.
  4. Carefully take the material.
  5. Take notes on which material is best with heat conductivity.

• Magnetic Properties: Can the material attract or repel magnets?

Reversible and Irreversible Changes

• Matter is constantly changing.
• Materials can be changed using different methods.
• Some changes don't form new substances (reversible), while others do (irreversible).

Explore 1: Changes Without Forming New Substances

• Materials needed: butter, metal spoon, dish, hot water.
  1. Place butter on a metal spoon.
  2. Gently place the spoon in a dish with hot water.
  3. Observe the butter after a few minutes.
  4. Record observations.
  5. Predict what would happen if the butter was placed in a freezer for approximately 15 minutes.
  6. Record predictions.
• Questions:
  • Would there be any changes in the substance?
  • Were there any new substances formed?

Reversible Change Defined

• A reversible change can be undone or reversed, returning the original substances.
• Reversible changes alter position, shape, color, size, or state without forming new materials.
• Examples: Melting, freezing, evaporating, condensing, dissolving, and filtering.

Explore 2: Changes Forming New Substances

• Materials needed: Plastic cup, baking soda, vinegar.
  1. Pour some vinegar into the cup.
  2. Add baking soda to the cup with the vinegar.
  3. Record observation.
• Questions:
  • Were there any changes in the material?
  • Were there any new substances formed?
  • Is it possible to return the material to its original state?
  • What do you think would happen if you add more baking soda or vinegar, or change the vinegar to lime juice?

Irreversible Change Defined

• An irreversible change cannot be changed back to its original form; a new substance is formed.
• Irreversible changes are permanent and cannot be undone.
• Example: You cannot change a cooked egg back into its original ingredients.
• Examples: Burning, heating, mixing.

States of Matter

Solids, Liquids, and Gases

Key Concepts

• States of matter: solid, liquid, gas.
• Processes: melting, freezing, evaporation, condensation.
• Matter has weight and takes up space.
• Matter is made up of atoms.

Explore 1: Common Characteristics

1. Find several liquids(the more the better)
2. Add some liquid in container
3. Use a measuring container
4. Pour liquids.

• Questions:
  • Did the volume change?
  • Did the state change?
  • Do liquid have volume?

Explore 2: Solids

1. Examine any solid such as: a rock, a marble, a coin, a paper clip, cotton ball, rubber band or any other solids you can find.
2. List as many properties as you can.
3. Place each solid on a tray. Then place each solid in a box.

• Questions:
  • Did the shape or size of any of the solid change at any time when placing in the different containers?

Comparison of States of Matter

• Solids: Definite volume and shape. Particles are close together and vibrate when heated. They are fixed in place.
• Liquids: Definite volume but no definite shape; takes the shape of its container. Particles can move from one place to another. When particles in a liquid are heated they move apart.
• Gases: No definite volume and no definite shape. Particles move easily in any direction to fill the space they are in.

Analogy

• Gas particles compared to few people moving about in a large space.

Changes in States of Matter

• Matter can change from one state to another when heated or cooled, but the substance itself doesn't change. For instance, water can exist as ice (solid), liquid water, or water vapor (gas), but it is still water H_2O.
• Molecules do not change; only their arrangement and the space between them change.

Types of Changes

• Melting: Solid becomes a liquid. The melting point is the temperature at which a substance begins to melt.
• Freezing: Liquid becomes a solid. The freezing point is the temperature at which a liquid becomes a solid. Pure water freezes at 0^\circ C and 32^ while salt water freezes at a lower temperature
• Evaporation: Liquid becomes a gas, usually occurring at the surface of a liquid.
• Condensation: Gas changes its state to become a liquid.

Terms Related to Changes of State

• Melting: Solid (Ice) to Liquid (Water)
• Evaporation: Liquid (Water) to Gas (Water Vapour)
• Condensation: Gas (Water Vapour) to Liquid (Water)
• Freezing: Liquid (Water) to Solid (Ice)

Human Body Systems

Overview

• The human body consists of millions of cells organized with special functions.
• Cells form tissues, tissues form organs, and organs belong to systems.
• Organ systems do not work in isolation but collaborate to carry out life processes.

Key Vocabulary

• Systems, circulatory, digestive, excretory, nervous, reproductive, respiratory, skeleton, muscular.

The Circulatory System

Function

• Responsible for the flow of blood throughout the body.
• Moves oxygen around the body.
• Moves carbon dioxide and other waste products out of the body.
• Moves nutrients and water to the cells in the body.

Parts of the Circulatory System

• Heart, blood vessels (arteries, veins, capillaries), and blood.

The Heart

• Main organ of the circulatory system.
• Pumps blood throughout the body.
• Made of cardiac muscle.
• Located a little to the left of the middle of your chest.
• Four chambers: right atrium, left atrium, right ventricle, left ventricle.
• Blood flows into the heart through the atrium.
• Blood leaves the heart from the ventricles.
• Valves separate chambers.

Have you ever wondered how big is the size of your heart?
Clench your fist-that is about how big the size of your heart.

The Blood

• Transports nutrients, removes waste materials, and acts as the body's defense against infections and diseases.
• Made up of red blood cells, white blood cells, platelets, and plasma.
• Red blood cells contain hemoglobin and function mainly as oxygen carriers.
• White blood cells make up the body's immune system.
• Platelets help the blood to clot. They help to stop bleeding when there is a cut.
• Plasma is a colourless, watery fluid of the blood. It acts as a vehicle to transport nutrients, carbon dioxide and other wastes products.

The Blood Vessels

• Arteries carry oxygenated blood away from the heart to the body.
• Veins carry deoxygenated blood back to the heart.
• Capillaries facilitate the transfer of substances between arteries and veins.

Circulation of Blood Through the Body

1. The heart pumps blood out a major artery
2. Arteries deliver blood to the organs of the body.
3. Organs of the body take food or oxygen from the blood.
4. Oxygen is returned to the heart
5. Veins return oxygen-poor blood to the lungs.
6. Oxygen - poor blood is enriched with oxygen in the lungs.

• Continuous exchange of oxygen-rich and oxygen-poor blood keeps us alive.

The Digestive System

Digestion

• Process by which food is broken down into small pieces and is made soluble so that it can pass into the blood stream.

The Process of Digestion

• Begins in the mouth with saliva and chewing.
• Enzymes present in the saliva change the starch into sugar, thereby beginning the process of digestion.
• Food enters the oesophagus and is squeezed down into the stomach through rhythmic contractions called peristalsis.
• The stomach produces gastric juices that further dissolve the food.
• Liquid food slowly moves into the small intestine where most of the digestion takes place.
• Nutrients are absorbed through the wall of the small intestine and into the blood stream.
• The nutrients are carried to all parts of the body.
• Water and waste enter the large intestine, where excess water is removed.
• Waste is stored in the rectum and expelled through the anus.

Parts of the Digestive System

• Alimentary canal: Long tube that starts at the mouth and ends at the anus.
• Includes the oesophagus, stomach, small intestine, and large intestine.
• Liver and pancreas produce enzymes that aid in digestion.

Liver

• The liver produces a green fluid called bile which aids the digestion of fats inside the small intestine.
• The pancreas produces pancreatic juices containing enzymes which digest proteins, starches and fats

The Excretory System

Function

• Removal of waste products from the body, including carbon dioxide, water, sweat, and heat.

Organs

• Kidneys, lungs, skin, and the liver.

Kidneys

• Filter wastes from the blood and produce urine.
• Urine is carried to the urinary bladder through the ureters.
• Urine is forced through the urethra out of the body by muscular contractions of the bladder.

Lungs

• Excrete carbon dioxide.

Skin

• Excretes water, salt, and other waste substances through sweat glands in the skin.
• The evaporation of sweat cools the body down.

The Nervous System

Two Main Systems

• The central nervous system
• The peripheral nervous system

Central Nervous System

• Brain and the spinal cord

Peripheral Nervous System

• Composed of the nerves throughout the body.

Function

• Controls everything that humans think, do or feel.

Brain Parts and Functions

• Cerebrum: Controls the senses, the imagination, and the thoughts
• Cerebellum: Controls movements, helps to maintain balance and co-ordinates the working of the muscles
• Brain stem: Helps with involuntary actions such as controlling heartbeats, digestion and breathing what happens automatically in the body.s

Spinal Cord

• Automatic actions in the body are controlled by the spinal cord.
• The spinal cord is like a cable through which messages travel up and down the body.

Peripheral Nervous System

• Nerves perform different tasks but all information is sent by specialized cells called neurons

Reproduction Defined

• The process that a living organism uses to produce more of its own kind.

The Reproductive System

Function

• Responsible for producing offspring.

Male Reproductive System

• Organs: penis and two testes or testicles.
• Function: To produce. maintain and transport sperm.

Female Reproductive System

• Organs: Ovaries, fallopian tubes, uterus (or womb), and vagina.
• Function: produce female sex cells called ova or eggs.

Sexual Reproduction in Humans

• Fertilization: Sperm combines with an egg cell in the fallopian tube.
• Pregnancy: The new cell develops into a baby in the uterus.
• Umbilical cord: Connects the baby to the placenta for nourishment.
• Birth: Baby leaves the mother's body through the vagina.

The Respiratory System

Function

• Responsible for supplying the body with oxygen and expelling carbon dioxide and water vapor.

Organs

• Nose, mouth, trachea (windpipe), bronchial tubes, lungs, alveoli sacs, and capillaries.

The Breathing Process

• Inhale or breathe in, air enters the nose or mouth and travels down to the trachea or windpipe
• As we exhale or breathe out through the nose or mouth.

The Skeletal and Muscular System

Function

• Provides support and enables movement.

The Skeletal System

• Framework of bones called the skeleton.

Functions

1. Provides support to the body by giving it shape and form and preventing the body from collapsing.
2. Protects the soft organs inside the body
3. Forms a necessary place of attachment for muscles that moves the body and anchors them firmly when they contract
4. Enables both movements and locomotion through the joints
5. Are held together by ligaments
6. Makes blood cells inside the bone marrow

Types of Joints

• Hinge joints allow movement
• Ball and socket joints allows to rotate in a circle.
• Fixed joints connects bones together and cannot move. An example include the bones in the skull.
• Gliding joints allows wrist to move.

The Muscular System

• Muscle cells work together to produce movement.
• The entire skeleton is covered with over six hundred (600) muscles.
• Muscles attached to bones by tendons.

Muscle Contractions

• Muscle fibers end in a strong, white, flexible cord called tendons.

Three Types of Muscles

• Cardiac Muscles:

  • Located only in the walls of the heart

  • Continuous, automated contractions

• Skeletal Muscles:

  • Attach to bones

  • Instructed by user

• Smooth Muscles:

  • Work automatically

  • Essential for keeping your heart beating and digestion flowing well

Muscle Movements

• Enable us to move our body parts.
• Keep us upright.
• Warm muscles.
• Supply us with oxygen and glucose.

Muscles and Bones

• Most of your muscles are arranged in pairs or groups, so that they put in opposite direction
• Two main muscles that move; biceps and triceps.

Balanced Diet

Nutrients Needed

• Carbohydrates, fats, proteins, vitamins, minerals, and water.

Carbohydrates

• Composed of carbon, hydrogen and oxygen.
• Provides the body with heat and energy.

Fats

• Protects organs and are sources of heat and energy.

Proteins

• Building block and are essential to growth

Vitamins

• Great for proper nutrition. Examples includes; fruit nad vegetables

Minerals

• Keeps the body running properly

Water

• Essential to good health.

Balanced Diet

Balanced diet is one which contains the correct amount of nutrients in the right proportions for all the needs of the body.
Fibre is also known as roughage, and is needed for peristalsis and emptying the large intestine. It keeps the bowels working properly.

Dietary Issues

• Obesity, diabetes, and malnutrition can be caused by poor eating habits or prolonged unbalanced diets.
• Obesity: Eating excess amounts of carbohydrates and fats increases its risks.
• Diabetes. Increase when consuming a high sugar diet.
• *Malnutrition: Lack of one essential diet. Shortage of certain nutrients

Deficiency Diseases

A disease to which arises due to the lack of important nutrients is called a deficiency disease.
Increasing the intake of vitamins and minerals can help prevent deficiency diseases.

Effect of vitamins

• Deficiency of Vitamin A increases a risk to loss of vision
• Deficiency of Vitamin B increases the chances of Beri - Beri.
• Deficiency of Vitamin C increases the chances of Scurvy.
• Deficiency of Vitamin D increases the chances of Rickets.

Minerals Deficiency diseases:

• Deficiency of Calcium results to softening of bones and muscle spasms and leg cramps.
• Deficiency of Phosphorus results to muscle cramps and problems in bones and teeth
• Deficiency of Sodium and Chlorine results to muscle weakness and paralysis
• Deficiency of Iron results to anaemia
• Deficiency of Iodine results to goitre