Senior Science Half Yearly Revision

Senior Science Half-Yearly Revision 1. emerge focus A property of the surface of a liquid. It is what nominates the surface mickle of liquid to be at parceled to anformer(a) surface, such as that of an some other portion of liquid. Surface tension is caused by cohesion (the attraction of jots to wish well molecules). Since the molecules on the surface of the liquid ar not surrounded by like molecules on all sides, they atomic number 18 more attracted to their neighbours on the surface. Mercury has a high surface tension. The meniscus of water is concave whilst the meniscus of atomic number 80 is convex.When a water strider is on the surface of the fluid, the surface under tension pass on behave like an elastic membrane. There will be a secondary depression on the surface of the water. The vertical components of the forces by the molecules on the object will balance break the weight of the object. 2. Biomaterials are special materials that are biocompatible. They are abl e to function in polish off with the living tissue with minimal rejection from the carcass. A biomedical device are implants that are engineered from biomaterial and designed to perform specific functions of the body.Titanium alloy low-density, non-toxic, biocompatible, strong, and non-corrosive. Plastics (polymers) biocompatible, not-toxic, non-corrosive, smooth, flexible, and low-density. 3. Muscles Muscles regard like bundles of pale pink tissue which pull the bone. Tendons Tendons are smart gaberdine tissues at the ends of the muscles that attach muscles to bones. Ligaments Ligaments connect bones to other bones at joints. They look like a shiny white viewing of the joint surfaces. Cartilage Between the bones is another shiny white material that is slippery.This is cartilage, which services the bones move with verboten grinding against one another, or without make trauma. 4. Why is it important for detergents to be biodegradable Non-biodegradable detergents could build up in waterways and cause signifi slewt and long-term damage. Biodegradable can be depressed down by the action of living things like bacteria and other microbes. 5. Transdermal Patches Slow and steady drug release directly into the bloodstream is the main benefit of skin patches. The drug is encased in a polymer which slowly releases the drug. E. g. Nicotine patches.Subdermal Implants Devices implanted under the skin are also cosmos developed to deliver drugs at a controlled rate. E. g. Contraceptives. It consists of six flexible ti tubes filled with a five-year supply of the contraceptive hormone. It is implanted in the stop number arm, and small amounts of the hormone continuously feed through the permeable tubes into the bloodstream. 6. wet is important in making medicines because generally, the more water soluble a drug, the quicker will be its assiduousness. It can be administered orally (as solutions, or in capsules or tablets) and by injection. Water acts as a solvent. . What causes the salubrious of a heartbeat The first heart sound (lub) is caused by the speedup and deceleration of blood and a vibration of the heart at the time of the diaphragm of the tricuspid and mitral valves. The second heart sound (dub) is caused by the same acceleration and deceleration of blood and vibrations at the time of closure of the pulmonic and aortic valves. Basically, the sound comes from the heart valves closing. 8. Surfactants are wetting agents that frown the surface tension of a liquid, allowing easier spreading, and lower the interfacial tension betwixt two liquids.Surfactants improve waters ability to wet things, spread over surfaces, and seep into dirty clothes fibres. One end of their molecule is attracted to water, while the other end is attracted to dirt and grease. So the surfactant molecules help water to bum a hold of grease, break it up, and wash it away. Soaps and detergents are both emulsifying agents and surfactants. 9. Colloid a type of mixture in which one substance is dispersed every bit throughout another. Particles that remain suspended for a long time. Suspension a mixture containing particles that settle out or form layers.Particles that settle out or form layers. Solute the substance to be dissolved. Solvent the substance in which to be dissolved in. Solution a group of molecules that are complicated up in a completely even distribution. Dissolved substances. assortment is when two or more different substances are mixed unitedly but not combined chemically. 10. Non-invasive medical techniques X-ray and Ultrasound. Advantages does make an moolah into the skin and short or no hospital stay. Disadvantages may not be able to detect all problems.Minimally invasive Keyhole operation and Angioplasty. Advantages get a detailed diagnostic report. Disadvantages long hospital stay. 11. hydrophilic refers to a physical property of a molecule that can transiently bond with water (H2O) throug h hydrogen bonding. Heads stick in the water, pursue stick out of the water. Hydrophobic is the physical property of a molecule that is repelled from a mass of water. Tails stick in the water, heads stick out of the water. 12. If plaque or fats get deposited in the arteries, it slowly blocks blood from menstruum freely to the heart.Plaque deposits that have built up inside arteries can be reduced by the technique called angioplasty. An empty and collapsed balloon on a guide wire, known as a balloon catheter, is passed into the narrow locations and then inflated to a fixed size. The balloon crushes the fatty deposits, so opening up the blood vessel to improved flow, and the balloon is then collapsed and withdrawn. 13. Lubricants utilise Reduces friction between moving parts. Precautions just about are flammable-keep away from flames. Pesticides Use Kills pests.Precautions Toxic-do not swallow, inhale or nightfall on skin. Solvents Use Dissolves dirt on clothes, turpentine to clean paintbrushes, oven cleaners to dissolve fat. Precautions Some are flammable and toxic. Drain and oven cleaners are corrosive and will burn skin badly. Do not swallow, inhale or spill on skin. Cosmetics Use Perfumes to produce a fragrant and pleasant scent. resolve to change appearance. Hair gel to change a particular hairstyle. Precautions whitethorn cause an allergic reaction in susceptible people. Sprays may be dangerous to inhale.Preservatives Use Prevent bacteria growing in food. Precautions whitethorn cause illness if eaten. Sulphur dioxide may cause asthma. May cause learning difficulties. 14. Diagram of the Heart 15. Parts of the Digestive System 16. The pH of the stomach is between 2 -3. This acidic condition will help kill bacteria and mix the food with digestive juices. The pH of the small intestine is between 7. 5-8. This alkaline condition helps in complete digestion and absorption of the food. 17. Role of skin Helps maintain a constant body temperature. Micro-flora Protects the body from disease. 18. Water-soluble vitamins 8 B vitamins and vitamin C. Fat-soluble vitamins Vitamins A, D, E and K. Water-soluble vitamins dissolve slowly in water, and in general, are readily excreted from the body, to the degree that urinary end product is a strong predictor of vitamin consumption. Because they are not readily stored, conformable daily intake is important. Fat-soluble vitamins are absorbed through the intestinal tract with the help of lipids (fats). They are more likely to accumulate in the body.