science year 9 revision
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science year 9 revision - Leaderboard
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| 🇬🇧 | 🇬🇧 |
| What is the key advantage of nano particles? | High surface area to volume ratio because volume decreases more rapidly than their surface area. |
| What is the diameter of nano particles? | The diameter of a nano particle is between 1nm - 100nm. |
| What are some of the uses of nano-technology? | You can use them as catalysts to speed up the rate of the chemical reaction. Only the exposed surface area is essential. Therefore need much less of a material made of nanoparticles than a material made of bigger particles. Because the nano particles would have more surface area for the given volume. another example is using nano-particles in electric circuits because some of them can conduct electricity. So you could make really tiny computer chips. another use is in nano-medicine which is the use of nanoparticles in medicine. for example, scientists are currently researching how we can use fullerenes (made from carbon atoms) to deliver drugs around the body. since they are so tiny they think they can easily deliver drugs directly to the inside of our cells. you can also use silver nanoparticles for anti-bacterial properties for example you can infuse them into surgical masks and plaster's to kill bacteria and reduce the chance of infection. |
| What are some issues with nano technology? | It is relatively new. so its effects on our bodies aren't fully understood. some people think we need to regulate them more strictly and clearly label anything that might contain nanoparticles until they have thoroughly been tested we cant be sure. |
| What is an example of all this? | If we use nanoparticles in sun cream it is more effective at protecting our skin against harm full uv rays and better skin coverage. but we are not sure if it can get into our bodies and damage our cells. and we don't know what happens when they enter the sea and it is possible that it damages the environment. |
| What will the resolution find us? | The shortest distance between two points on a specimen that can still be distinguished as two separate entities. |
| What is the resolution of a light microscope? | 0.2 micro meter's |
| What is the resolution of a electron microscope? | Up to 0.1 nano meter's |
| What is the enlarged appearance of an object called? | Image (image size) |
| What is the material your looking at called? | Object (real size) |
| How do we calculate magnification? | Magnification = image size divided by object size |
| What is a kilo meter in meter's? | (10 to the power of 3 meters) |
| What is millimetres in meters? | (10 to the power of -3 meters) |
| What is micrometers in meters? | (10 to the power of -6 meters) |
| What is nano meters in meters? | (10 to the power of -9 meters) |
| What is homeostasis? | Homeostasis is the regulation of conditions inside the body to maintain a stable internal environment, in response to both internal and external. |
| How do our cells stay 37 degrees in all types of weather? | Our body uses automatic control systems. which is when our body recognizes when there is a change from optimal conditions and sends a signal to reverse the change. so the levels go back to normal. |
| What are the three main components of automatic control systems? | Receptors - detect a change such as a rise in temperature coordination centres such as the brain and spinal cord -interpret that change -what needs to be don? effectors - carry out the change such as muscles or glands which release hormones |
| How do we send signals between the three main components of the automatic control system? | We use our nervous system and endocrine system. the nervous system sends very fast and precise electrical impulses through nerves which allows us to respond to things very quickly such as when we touch a sharp object. the endocrine system relies on hormones(small chemicals released into the bloodstream). Although they travel around the entire body they only affect certain cells that have the right receptors. the endocrine system is slower, longer-lasting and more generalised than the nervous system. |
| How does negative feedback work? | Whenever something gets too high for example the level of glucose in our blood the negative feedback decreases it again to turn it to normal but if it got decreased too much then the negative feedback will increase it again to make it go back to normal. But if it goes high then the same thing will happen all over again. |
| What is an example of this in real life? | If you walk into a room and it's too cold. The low temperature will be detected by receptors such as in our skin and the nervous system will then send the information to the coordination centre such as the brain and spinal cord these interpret the information then send another set of signals to the effectors such as our muscles that can carry out the useful response like shivering. after a bit of time the shivering will increase our body temperature and we will return to normal. but if it goes too far and instead of turning to normal, we get too hot. then a different set of receptors detect the heat and send their own signals to our coordination system and then a different group of effectors to carry out their own response which is sweating then our temperature will go back to normal and if we get too cold the same thing will happen all over again. |
| How does the atmosphere regulate the earths temperature? | The suns heat energy passes down towards the earth in a form of light rays. It passes through the atmosphere and hits the surface of the earth. some of the energy is absorbed by the earth but most of it is either re emitted or reflected back into the atmosphere towards space. some radiation does make it back to space. but most of it hits particles of gas in the atmosphere which will absorb all of the energy. after a short delay the particles will then re emit the energy in random directions. This means that some of the energy will be re emitted to space and some towards the earth and some will be absorbed by other gas particle and re emit the energy over and over again. which means the heat energy stays close to earth far longer then if there was no atmosphere and that is the process that keeps the earth at a warm and stable temperature. |
| What what molecules does this happen with? | Carbon dioxide methane and water |
| What are the gasses in the atmosphere called? | Greenhouse gasses |
| What is responsible for global warming? | The greenhouse gasses. |
| What are the consequences of global warming? | Droughts, hurricanes and floods will become more common and more severe we refer to this change as climate change. another consequence is sea level rising one way there is sea level rising is because the hot weather is causing ice to melt which will then float in the ocean and another way the sea level rises is when the water in the ocean warms up the water expands and its volume will increase making the sea level rise even more. this can cause seasonal flooding and submersion of entire islands/coastal towns. |
| What else will climate change have an impact on? | Climate change can also have a more general impact on the wild organisms across the world as temperatures and rainfall patterns change species that were perfectly adapted to their environment might not be able to survive anymore in some cases species might be able to adapt to new conditions or migrate to other regions where the conditions are a bit better. an example of this is that some species are now moving towards the poles where its a lot cooler. unfortunately, some species can adapt or move to other regions fast enough and biodiversity is likely to fall dramatically in the next couple of decades |
| What are non-renewable resources? | Resources that cant be renewed(it runs out) eg natural gas coal oil (fossil fuels) |
| What are renewable resources? | Resources that can be renewed eg solar, wind, hydroelectric, geothermal, tidal and biofuels. |
| What resources did trains use compared to now? | Trains used coal and now they use electricity |
| What are biofuels made from? | They are created from renewable resources like plants. |
| How is natural gas used to heat radiators? | The natural gas is burnt to heat water and then the hot water is pumped into our radiators and then the thermal energy is transferred in the air in our rooms to help keep us warm. |
| How can we use renewable resources for heating? | Solar water heaters work by using the suns energy to heat water which can then be pumped through the radiators in our houses. and biofuels can be burned for heat. |
| Is electricity a renewable resource? | It depends on how it is made most of our electricity run on non renewable resources. |
| What are the four main stages of the life cycle assessment? | 1. extracting and processing the raw materials 2. manufacturing and packaging your product 3. using your product 4. disposing of it |
| What are some of the problems with extracting and processing the raw materials? | It can damage the local environment eg cutting down trees and digging huge mines. it can also indirectly damage the environment because huge amounts of energy is required like when extracting metals from their ores or from fractional distillation of crude oil and lots of pollutants can be released. |
| What are the three main problems with manufacturing and packaging? | Energy use, the release of pollution like carbon monoxide and hydrogen chloride and lastly waste products which can be used as raw materials for something else but usually they are useless. and they have to be disposed of. |
| When considering the impact of using the product what two things do we need to look at? | 1. how much damage it does during its lifetime - eg how polluting driving a car is or how much damage fertilizers do when they run of into the environment 2. how long the product is used for - eg if you buy a really nice bag and you use it a thousand times that is different to a paper bag which you will only use maybe once |
| What else do we have to consider? | How we dispose of the product - if we place it in landfill then that could take up space that could have been used for nature and chemicals might seep out into the surrounding ecosystems - if we burn the waste products they might release pollutants into the atmosphere - either way, we have to use energy to transport the items to the landfill or to the incinerator |
| What are the raw materials for plastic and paper bags? | Plastic bags - crude oil paper bag - wood |
| Manufacturing and packaging for plastic and paper bags | Plastic bag - hydro carbons from fractional distillation - cracked to make alkenes -polymerisation paper bag - timber has to be pulped - loads of energy - loads of waste |
| Using the product for plastic and paper bags | Plastic - can be reused multiple times paper bag - single use |
| Disposing of paper and plastic bags | Plastic - non biodegradable - take up space in landfill - get into the wild and harm animals paper - biodegradable - non toxic |
| What are the limitations of the life cycle assessment? | 1. making products involves loads of steps - almost impossible to quantify them - even if u do find all the data like how much energy was used you will still not be able to asses the harm of each and every step 2. because the life cycle assessment is so complex they can easily be manipulated to support a company which may be done to give the company positive advertising |
| What is the atomic theory? | The idea that all things were made from tiny particles that cant be broken down further and is separated from each other by an empty space. this proposed by a guy called democritus who was alive around 500 B.C |
| How did john Dalton describe atoms and when? | In1800s Dalton described atoms as solid spheres. he also suggested different types of spheres make up different elements |
| How did JJ Thomson describe the atom and when? | In 1897 JJ Thomson came up with the plum pudding model. he did an experiment which showed atoms could not be solid spheres and instead they must have contained negatively charged particles which we now know as electrons. so the plum pudding model is a general ball of positive charge (the pudding) and electrons stuck in it (the plums) |
| What did ernest rutherford find out and when? | In 1909 Ernest took positively charged particles and fired it at a thin sheet of gold the idea was that if the positive charge in the atom was generally spread out as JJ Thomson proposed in the plum pudding model then the particles should go right through it because there would not be any concentrated positive charge to repel them. weirdly though some of the particles were deflected to the side some even bounced right back. this proved JJ theory wrong |
| What was rutherfords model? | Rutherford came up with a nuclear model he proposed that instead of a field of a positive charge there was some sort of compact nucleus which contained all of the positive charges of the atom and he thought the negative charge existed in a sort of cloud around this central nucleus. but there some doubts on rutherfords model there didn't seem to be anything stopping this cloud of negative charge rushing in towards the positive nucleus meaning the atom should just automatically collapse wich we know it doesnt. |