Senior Science Half-Yearly Revision
Senior Science Half-Yearly Revision
1. Surface tension - A property of the surface of a liquid. It is what causes the surface portion of liquid to be attracted to another surface, such as that of another portion of liquid. Surface tension is caused by cohesion (the attraction of molecules to like molecules). Since the molecules on the surface of the liquid are not surrounded by like molecules on all sides, they are more attracted to their neighbours on the surface.
Mercury has a high surface tension. The meniscus of water is concave whilst the meniscus of mercury is convex.
When a water strider is on the surface of the fluid, the surface under tension will behave like an elastic membrane. There will be a small depression on the surface …show more content…
Plastics (polymers) – biocompatible, not-toxic, non-corrosive, smooth, flexible, and low-density.
3. Muscles – Muscles look like bundles of pale pink tissue which pull the bone.
Tendons - Tendons are shiny white 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 covering of the joint surfaces.
Cartilage - Between the bones is another shiny white material that is slippery. This is cartilage, which helps the bones move without grinding against one another, or without causing trauma.
4. Why is it important for detergents to be biodegradable – Non-biodegradable detergents could build up in waterways and cause significant and long-term damage. Biodegradable can be broken 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 …show more content…
Water is important in making medicines because generally, the more water soluble a drug, the quicker will be its absorption. It can be administered orally (as solutions, or in capsules or tablets) and by injection. Water acts as a solvent.
7. What causes the sound of a heartbeat - The first heart sound (lub) is caused by the acceleration and deceleration of blood and a vibration of the heart at the time of the closure 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 lower the surface tension of a liquid, allowing easier spreading, and lower the interfacial tension between two liquids. Surfactants improve water's 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 get a hold of grease, break it up, and wash it away. Soaps and detergents are both emulsifying agents and
1. Surface tension - A property of the surface of a liquid. It is what causes the surface portion of liquid to be attracted to another surface, such as that of another portion of liquid. Surface tension is caused by cohesion (the attraction of molecules to like molecules). Since the molecules on the surface of the liquid are not surrounded by like molecules on all sides, they are more attracted to their neighbours on the surface.
Mercury has a high surface tension. The meniscus of water is concave whilst the meniscus of mercury is convex.
When a water strider is on the surface of the fluid, the surface under tension will behave like an elastic membrane. There will be a small depression on the surface …show more content…
Plastics (polymers) – biocompatible, not-toxic, non-corrosive, smooth, flexible, and low-density.
3. Muscles – Muscles look like bundles of pale pink tissue which pull the bone.
Tendons - Tendons are shiny white 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 covering of the joint surfaces.
Cartilage - Between the bones is another shiny white material that is slippery. This is cartilage, which helps the bones move without grinding against one another, or without causing trauma.
4. Why is it important for detergents to be biodegradable – Non-biodegradable detergents could build up in waterways and cause significant and long-term damage. Biodegradable can be broken 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 …show more content…
Water is important in making medicines because generally, the more water soluble a drug, the quicker will be its absorption. It can be administered orally (as solutions, or in capsules or tablets) and by injection. Water acts as a solvent.
7. What causes the sound of a heartbeat - The first heart sound (lub) is caused by the acceleration and deceleration of blood and a vibration of the heart at the time of the closure 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 lower the surface tension of a liquid, allowing easier spreading, and lower the interfacial tension between two liquids. Surfactants improve water's 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 get a hold of grease, break it up, and wash it away. Soaps and detergents are both emulsifying agents and