Science

                                                                       Sound What is sound? In physics, sound is  a vibration that propagates as an acoustic wave, through a transmission medium such as a gas, liquid or solid . In human physiology and psychology, sound is the reception of such waves and their perception by the brain.  Sound is created when something vibrates and sends waves of energy (vibration) into our ears. The vibrations travel through the air or another medium (solid, liquid or gas) to the ear. The stronger the vibrations, the louder the sound. What are the 3 types of sound? Sound waves are characterized into three types. Audible sound waves are those that humans can hear. Infrasonic waves are those that are too low-frequency (below 20 Hz) for humans to hear. Ultrasonic sounds waves are those that are too high-frequency (above 20,000 Hz) for humans to hear. What are the 4 properties of sound? Since sound is a wave, it has all of the properties attributed to any wave

                                                                          Forces   Our life is full of forces. We cannot see them but we can see how they affect things. All sports involve forces. You can use a force when you run or when you ride a bike.  When you take part in certain sports you need special equipment to protect you from some  forces or help you to produce bigger  forces. Many sports would not be possible without modern technology.   For many  forces, the thing provided the  force needs to touch an object before the  force can affect it. These are called contact forces. For example when you throw a ball, you need to touch it to exert a force on it. When you need to go down a steep hill on a bicycle, the brakes need to touch the wheel to produce friction to slow you down . Contact forces include friction, air resistance, water resistance and  up thrust (the force that makes things float). Some  forces can affect an object from a distance. these are call non-contact  forc

                    Movement And Joints Fixed joints:  Synarthroses (immovable joints), also known as fixed or fibrous joints, are defined as  two or more bones in close proximity that have no movement . An example of immovable joints are the plates of the skull.  The joints in which bones cannot move or bend are called immovable or fixed joints. Examples include  skull bones, teeth in sockets of jaw. Moveable joints A moveable is a joint that can move below would be the examples of moveable joints:  Hinge joint: Hinge joints are  a type of joint that functions much like the hinge on a door, allowing bones to move in one direction back and forth with limited motion along other planes . The fingers, toes, elbows, knees, and ankles contain hinge joints. Hinge joints are complex and contain many muscles and tissues. Pivot joints:  pivot joint, also called rotary joint, or trochoid joint, in vertebrate anatomy,  a freely moveable joint (diarthrosis) that allows only rotary movement around

                                                                    Forces What is a force? A force is The push or pull on an object with mass causes it to change its velocity . Force is an external agent capable of changing a body's state of rest or motions It has a magnitude and a directions. They are measured in Newtons.     types of force .. . Gravitational force.-    a force of attraction (attractive force) that attracts all physical forms having mass Non-contact forces- they pull or push on objects without touching them Magnetic force.-  attraction or repulsion that arises between electrically charged particles because of their motion Nuclear force.-  a force that acts between the protons and neutrons of atoms . Frictional force.-  t he force that resists motion when the surface of one object comes in contact with the surface of another Frictional force.-  t he force that resists motion when the surface of one object comes in contact with the surface of another              E

                                                                  Science sun The Sun  is the only star in our solar system. It is the centre of our solar system, and its gravity holds the solar system together. its   Temperature: 5,973°C to 15,000,000°C.               mercury At a distance of only about 1/3 of Earth's distance to Sun, Mercury is the first planet in our Solar System . With a diameter of only 4880 kilometres (3032 miles) Mercury is the smallest planet in the Solar System. It is barely bigger than our Moon. Not only is Mercury the smallest planet, it is also shrinking! Venus Venus is the second closest planet to The Sun. It is the hottest planet in the Solar System. There are yellow clouds on Venus. Venus is the only planet in our Solar System that rotates Clockwise. A day on Venus lasts 243 Earth Days. Earth Earth is not flat, but it's not perfectly round either. The days are getting longer. There weren't always several continents. Earth's icy times. Th