Just a little help to prepare your Science Test.

The Endocrine System.
The endocrine system manages and coordinates important functions like growth and reproduction. It is made up of glands which produce hormones.

Endocrine Glands.
• Thyroid gland: this gland produces hormones like thyroxid which lets our body absorb nutrients.
• Pancreas: this gland produces insulin which regulates the amount of sugar in blood.
• Ovaries and Testes: thes glands produce sex hormones.
• Pituitary gland: this gland coordinates other endocrine glands.

Energy:
Energy produces all the changes around us.

Sources of Energy:
They enable machines to do things. There are two types of sources of energy:
• Renewable sources of energy like wind or sunlight.
• Non-renewable sources of energy like oil, coal or natural gas.

Types of energy:
• Mechanical energy: energy of things in motion
• Chemical energy: energy produced by fossil fuels.
• Thermal energy: energy released as heat.
• Electrical energy: energy used by electrical devises.
• Nuclear energy: energy from uranium of plutonium.
• Light energy: energy from the light.

Transformation of energy:
• Electrical into mechanical: fan
• Electrical into light: bulb
• Electrica into thermal: heater.
• Nuclear into electrical: nuclear plant.

Light:
Light is a form of energy. It moves at 300000 Km per second. It moves in a straight way.

Objects block light in different ways:
• Opaque objects: the absorb or reflect light.
• Traslucent objects: they allow some light to pass through.
• Transparent objects: the allow light to pass through.

Reflection of light:
When light hits and opaque object, it is reflected and changes direction.