science gcse core, additional and triple science powerpoints

1. P2 Radiation and life Route map Over the next 12 lessons you will study : Friday 21 October 2011 P2.1 Sunlight, the atmosphere & life P2.2 Ozone protection P2.3 Radiation models P2.4 Electromagnetic radiation End of module test P2.5 Using radiation P2.6 Mobile phones and Health P2.7 Health Studies P2.8 X-ray safety P2.9 Global warming P2.10 The carbon cycle P2.11 Changing climates? P2.12 Time for action?

3. P2.1 Sunlight, the atmosphere and life Decide whether the following statements are true or false: Introduction: Ultraviolet radiation (UV), in sunlight can cause skin cancer. Melanin a brown pigment in the skin can provide protection from the sun. People with fair skin have to protect it from too much sun exposure as it can easily burn and cause cancer. However human skin absorbs sunlight to make vitamin D which is good for muscles, bones and the immune system. The risks and benefits have to be balanced to stay healthy in the sun. Friday 21 October 2011 Know this: a: Know that exposure to UV light can increase the risk of contracting cause cancer. b: Know the risks and benefits of exposure to UV and that the skin can manufacture Vitamin D when exposed to UV light Extension questions: 1: What type of radiation causes skin cancer ? 2: What brown skin pigment can protect you from the sun and why do fairer skinned people have to be extra careful in the sun ? 4: List three benefits of sun exposure ? 5: Explain why the incidence of skin cancer rises as you age and why is skin cancer rates higher in white females compared with white males ? 6: Why do Albinos who lack skin pigmentation rarely live beyond 25 ?

4. P2.1 a Look at the photograph and information and answer all the questions: Over a lifetime the risk of developing skin cancer is 1 in 117. Scientists believe there is a correlation between sun exposure and skin cancer. In this correlation, the outcome is skin cancer and the factor is exposure to UV light during a person’s lifetime. However there are other factors for example a person age, skin colour and diet. Explain why light skinned Europeans are more at risk than dark skinned Africans ? Moderate exposure to UV light allows the skin to make vitamin D. Is this a positive benefit form UV light and why ? What does the word correlation mean and explain why you have to do further work to prove a correlation or link between a factor like UV and an outcome like cancer ? Normal Melanoma The mole on the right displays asymmetry The mole on the right display an undefined border Key concepts

5. P2.1 b Look at the photograph and information and answer all the questions: Exposure to UV-B and UV-B from the sun is the primary cause of skin cancer and responsible for around 80% of cases of melanoma, the most dangerous kind of skin cancer”. New figures out now confirm that skin cancer is the most common form of the disease for females in their twenties. A staggering rate of one malignant melanoma a day is now being diagnosed. Look at the bar chart opposite, explain the tend over the last 10 years in a) the number of cases of skin cancer and b) deaths from skin cancer ? How can you protect yourself from contracting skin cancer ? UV light is classified into three ranges a) what are they and b) which one is the most harmful and which is the least harmful ? Key concepts

6. Key concepts P2.1 c Look at the photograph and information and answer all the questions: How does the a) frequency and b) the wave speed change from radio waves to gamma rays ? Explain what happens to the penetration ability as you move form radio waves to gamma waves ? Doctors exploit the penetrating ability of which wave to examine broken bones ? Electromagnetic waves are transverse waves which travel at a speed of 300,000 kms -1 through a vacuum. This is usually called the speed of light. All e.m waves transfer energy from one place to another and like visible light can be reflected by smooth, hard surface or refracted when they travel form one material to another. through transparent materials. The electromagnetic spectrum 10 -9 m 10 -6 m 10 -3 m 1 10 3 m 10 6 m 10 9 m Photon energy (J) Increasing energy and penetration Photons and the electromagnetic spectrum

7. P2.1 Plenary Lesson summary: Decide whether the following statements are true or false : False True False True False True bones vitamin brown sunlight The Australians launch a massive campaign to reduce deaths from skin cancer due to over exposure to UV light. They called it the ‘slip slap slop campaign. This slogan encourage people to slip on a ‘T’ shirt, slap on a hat and slop on some sun cream. The campaign reduce death form skin cancer by up to 22% over a five year period How Science Works: Friday 21 October 2011 Research into the role of sunlight, how plants use it during photosynthesis and how the ozone layer absorbs harmful UV rays form the sun and prevents then reaching the Earth’s surface. Preparing for the next lesson: The ultraviolet radiation (UV), in _______ can cause skin cancer. Melanin a _______ pigment in the skin can provide protection from the sun. However human skin absorbs sunlight to make ________ D which is good for muscles and _______. 3: Vitamin D is good for the immune system ? 2: Ultra violet light can cause skin cancer ? 1: Melanin can’t protect you from exposure to UV light ?

9. P2.2 Ozone protection Decide whether the following statements are true or false: Introduction: The atmosphere transmits some radiation (visible light, radio radiation) but absorbs other types of radiation (X-rays and UV radiation). The atmosphere is a mixture of gases. The upper atmosphere is called the ozone layer which can absorb harmful uv radiation to make free molecules of oxygen. UV radiation is dangerous because it can cause skin cancer and rising sea levels. Extension questions: 1: White light is a mixture of seven different colours. A student explains to his friend that plants do not use the energy contained in green light. Is he wrong or right and explain why ? 2: Where in the atmosphere do we find the ozone layer and explain why it is so important ? 3: Why is UV radiation dangerous to all life forms ? 4: How have CFCs damaged the ozone layer over the last 20 to 30 years and why have their use now be banned globally ? Know this: a: Know that sun light energy is used by plants during photosynthesis. b: Know that the ozone layer protects us from harmful levels of UV radiation. Friday 21 October 2011

10. P2.2 a Look at the photograph and information and answer all the questions: Plants use light energy to split water into hydrogen and oxygen, The hydrogen then combines with carbon dioxide to form glucose. The rate of photosynthesis in green plants speeds up as light intensity increases, but only up to a point. The overall rate may also be limited by the carbon dioxide levels and the temperature. During a summer’s day at what part of the day would you expect the rate of photosynthesis to be the highest ? What specialised cell found in the upper part of the leaf contains chloroplasts which produces glucose and oxygen ? Plants can use starch made from glucose during respiration. Write a word equation to summarise respiration ? Light energy Light energy from sunlight Equation for photosynthesis Light energy wrong wavelength 6CO 2 (g) + 6H 2 O (l) C 6 H 12 O 6 (s) unused 35% 63% Only 2% of light energy is used for photosynthesis Key concepts

11. P2.2 b Look at the photograph and information and answer all the questions: Chlorophyll, the pigment inside chloroplasts absorbs strongly between 400 nm and 550 nm (blue light) and between 630 nm and 600 nm (red light). Plants obtain all their energy from the blue and red parts of the spectrum, however, between 500-600nm, where very little light is absorbed. This light in the green region of the spectrum is reflected. This is the reason plants appear green. Explain why plants would not photosynthesis if you shone green light on their leaves ? Red seaweed is found in shallow rock pools. Which colour of light does this seaweed use during photosynthesis ? Explain how plant leaves selectively absorb light ? photosynthesis carbon dioxide water glucose oxygen Key concepts

12. P2.2 c Look at the photograph and information and answer all the questions: Ozone is made from three atoms of oxygen. It is found in a thin layer high up in our own atmosphere. The ozone layer absorbs harmful UV radiation from the Sun. Without ozone life would not exist on this planet. CFC’s, the gases used in spray cans have damaged the ozone layer. The two picture opposite left show the hole in the ozone layer over Antarctica in 1997 and 2007. Governments around the World have now banned the use of CFCs in spray cans. Do you think this will help reduce the damage to the ozone layer ? Skin cancer is cause by excessive exposure to UV radiation. Do you think there will be an increase in skin cancer over the next few years ? Explain in a table the mains differences between acid rain, global warming and damage to Earth's ozone layer ? The ozone layer 1997 2007 Key concepts

13. P2.2 Plenary Lesson summary: Decide whether the following statements are true or false : False True False True False True cancer radiation atmosphere oxygen How Science Works: Friday 21 October 2011 Research into radiation models and how light is detected, reflected and reacted form a point source. Find out about how other waves like infra red and radio waves are used to communicate of transmit information. Preparing for the next lesson: The upper __________ is called the ozone layer which can absorb harmful uv __________ to make free molecules of _________. Uv radiation is dangerous because it can cause skin ________ and rising sea levels. 3: The ozone layer protects us from UV radiation ? 2: CFC’s are good for the ozone layer ? 1: The atmosphere is made up of a mixture of gases ? It are that we are put at risk by X rays or gamma rays, but every day and particularly during our summer we are exposed to UV light. These rays can penetrate the first few layers of the skin and causes changes to the skin’s DNA leading to fatal skin cancer. Sun creams contain metal oxide which act as a barrier and prevent UV (particularly UV-C) radiation form striking our skin.

16. P2.3 a Look at the photograph and information and answer all the questions: Non luminous objects do not give out their own light. In order for to see them and determine their shape, texture and colour light from a luminous object must bounce off the object and into the eye. When light hits an object it can pass through if the object is transparent, bounce back if the object is smooth and shiny or be absorbed it the object is dark and dull. Give two examples of everyday objects that are a) transparent b) smooth and shiny and c) dull and dark ? Explain why a matt black car will become hotter on a summer’s day when compared to a metallic white or silver car of the same make and model ? Look at the picture below left, explain why the images we see of the cat and the tomato are totally different and yet both objects are illuminated by the same light source ? observer light source observer light source observer light source Looking at reflection and absorption of light Key concepts

17. P2.3 b Look at the photograph and information and answer all the questions: Radio waves have the longest wavelengths. These waves can be longer than a football field. Radio waves carry signals for your radios and televisions. This is then used to compile song or a picture with sound. Infra red is used by TV remote control. Different flickering patterns sent form the control unit and detected by the television can change channels and change the volume Explain how a radio antenna works ? Does a television work using the same or different technology when compared to a radio ? Infra red also transfers heat energy form a source to an absorber. Give an example of three sources of infra red energy ? radio waves Infra red Key concepts

18. P2.3 Plenary Lesson summary: Decide whether the following statements are true or false : False True False True False True journey radio waves radiation detector How Science Works: Friday 21 October 2011 Research into the effects of radiation, for example how infra red can have a heating effect, how light can cause chemical changes in plants, how radio weaves can transmit information and how ionising radiation like UV, X rays and Gamma can damage DNA and lead to cancers. Preparing for the next lesson: 3: Visible light can be reflected? 2: Objects don’t absorb radiation ? 1: Microwave is a type of electromagnetic radiation ? Gamma, microwave, _________ and light are all different types of electromagnetic __________ they all have a source, ________ and a __________. This type of radiation can be used in remote controls to communicate and control information. A microwave oven uses microwaves to heat food. Microwaves are radio waves. In the case of microwave ovens, the commonly used radio wave frequency is roughly 2,500 megahertz (2.5 gigahertz). Radio waves in this frequency range have an interesting property: They are absorbed by water, fats and sugars.

20. P2.4 Electromagnetic radiation Decide whether the following statements are true or false: Introduction: When electromagnetic radiation is absorbed by objects it can: Make patterns of electric currents in metals (radio waves), heat up objects (microwaves), cause chemical changes (light waves in photosynthesis), damage living cells ( gamma waves). Photons are energy packets which make up radiation. The strength of electromagnetic radiation depends on the number of photons and the energy each photon carries. Extension questions: 1: Look at the following waves, sort them into ionising and non ionising radiation: gamma rays, radio waves, infra red, light, UV and X rays ? 2: Which wave a) is good at transferring heat energy to an object and which wave is detected by the human eye 3: What do a) microwaves do when they are absorbed by objects b) light waves do when they are absorbed by leaves and c) gamma waves do when they are absorbed by the body ? 4: What does the strength of electromagnetic radiation depend on ? Know this: a: Know that electromagnetic radiation effects objects in different ways . b: Know that photons are energy packets which make up radiation. Friday 21 October 2011

21. P2.4 a Look at the photograph and information and answer all the questions: Electromagnetic radiation can be though of as lines that show pathways of radiation, or waves spreading out like ripple in a pond or individual photons transferring energy from the source to the absorbing material. EM radiation is classified into non ionising (radio, microwaves, infra red, visible light) and ionising radiation (UV X-rays, gamma rays) Ionising radiation including UV light and X rays can cause what if absorbed by cells within the body ? Which type of wave can a) the human eye detect and b) human skin detect ? Which type of waves is used to a) transmit information to make a TV picture and b) to identify a broken bone ? observer observer observer journey journey journey Key concepts

23. P2.4 c Look at the photograph and information and answer all the questions: In some cancers, cancerous cell are irradiated using a gamma source. The cells are killed by the destructive nature of the gamma radiation. Furthermore, where surgery is impossible, radiotherapy can be used, although the success rate is not high. Killing all the cancerous cells whilst leaving healthy ones intact is very difficult, even for the most skilled surgeons. Explain why not all brain tumours can removed using normal surgical procedures involving a scalpel ? Why would using X rays not work when treating brain cancers ? In the picture below left, the brain tumour is pictured shrinking after successive exposure to gamma rays. Explain why the cancer has shrunk ? gamma rays radiation journey Key concepts

24. P2.4 d Look at the photograph and information and answer all the questions: X-rays are a form of electromagnetic radiation, just like visible light. X-ray machines sends are individual x-ray photons. These pass through the body. A computer or special film is used to record the images that are created. Structures that are dense (such as bone) will block most of the x-ray particles, and will appear white. Why do radiographers, people who use x ray machines protect themselves from regular exposure to x rays ? Name one other use for X rays other than imaging broken bones ? Explain why X-ray photography produce images of the bones in our body but not the flesh ? X rays radiation journey Key concepts

25. P2.4 e Look at the photograph and information and answer all the questions: Radio waves have the longest wavelengths. These waves can be longer than a football field. Radio waves carry signals for your radios and televisions. The antennae on your television set receive the signal, in the form of electromagnetic waves, that is broadcasted from the television station. This is then used to compile a picture with sound. Explain how a radio antenna works ? Does a television work using the same or different technology when compared to a radio ? Blue uses low powered radio waves for wire communication between what type of devices ? radio waves radiation journey Key concepts

26. P2.4 Plenary Lesson summary: Decide whether the following statements are true or false : False True False True False True damage currents heat absorbed Radio waves are the largest electromagnetic waves they range from 1cm – over 100m and carry the least amount of energy ! Despite this when they strike a television or radio aerial they induce a small current. Patters of electric current in radio or television aerials can be turned into information to compile a song or a television picture with sound How Science Works: Friday 21 October 2011 Research into using radiation for different uses for example microwaves for mobile phones, radar and cooking. Preparing for the next lesson: 3: Photons are energy packets which make up radiation ? 2: Radio waves are ionizing ? 1: X-rays are non-ionizing ? When electromagnetic radiation is _________ by objects it can: Make patterns of electric __________ in metals (radio waves), _______ up objects (microwaves), cause chemical changes (light waves in photosynthesis), _________ living cells (gamma waves).

28. P2.5 Using radiation Extension questions: 1: Name three uses of a microwave oven ? 2: Microwaves are also used by what other device to transmit information from a device to base stations and then to other users ? 3: What two things does the heating effect of a microwave oven depend on and how is this heating effect balanced out ? 4: What materials a) reflect radiation in a microwave b) absorb radiation in a microwave and c) transmit radiation in a microwave ? 5: What type so fem waves does conventional oven use ? Know this: a: Know that microwaves use radiation to heat up food by causing the molecules inside them to vibrate. b: Know that the heating effect of a microwave depends on its intensity and duration. Friday 21 October 2011 Introduction: In a microwave some materials reflect radiation ( metal objects), some materials transmit radiation (glasses and plates) and some materials absorb radiation (food containing water, fat or sugar). The heating effect of a microwave depends on its intensity and duration. The rotating blades and a rotating plate in the microwave help balance out the heat inside which causes the molecules inside food to vibrate and heat up.

29. P2.5 a Look at the photograph and information and answer all the questions: Microwaves are electromagnetic waves with wavelengths ranging from as long as one meter to as short as one millimetre Microwaves work by shooting tiny waves called microwaves through food. When the microwaves go through the food, they make the water molecules vibrate. This increase the kinetic or heat energy of the food. Heavy uses of mobile phones report a ‘heating effect’ in the left or right ear when using a mobile phone. Does heavy use of mobile phones pose a health risk ? Mobile phones uses microwaves to transmit information from one place to another. List three other uses of microwaves ? Look at the picture above left, it is of a microwave oven. It uses microwaves to heat food. Explain how this happens ? Microwaves and microwave ovens Microwaves used to cook food Key concepts

30. P2.5 b Look at the photograph and information and answer all the questions: Microwave heating works by heating the water in foods. The frequency used in microwave ovens optimally heats water molecules. The microwave energy is converted into heat energy of the water molecules, which in turn heat the other molecules in the food. That is why dry foods such as rice and pasta will not cook in a microwave unless they are in some water. Describe three safety features of the modern microwave oven ? Why is important that none of the microwave radiation is allowed to escape form within the microwave oven ? Explain why microwave ovens are not very good for cooking food items like sausages and bacon ? microwaves water molecules rotate Key concepts

31. P2.5 Plenary Lesson summary: Decide whether the following statements are true or false : False True False True False True absorb transmit radiation microwave Microwaves typically use between 600 and 800 watts of electrical energy to rapidly heat foods in the kitchen, The great selling point of a microwave is that it is quick, cheap to buy, safe to use and does not alter the taste of most foods that it heats or cooks. Microwaves do have their limitations, for example they cannot brown a food product in the way that conventional grills can using infra red radiation. How Science Works: Friday 21 October 2011 Research into how mobile phone use microwaves to transfer information form the mobile phone to the base station and whether the microwaves sued by mobile poses a health risk to humans. Preparing for the next lesson: 3: Microwave radiation causes the molecules in food to vibrate and heat up ? 2: Water absorbs microwave radiation ? 1: Microwaves use radio waves to warm or heat foods ? In a ___________ some materials reflect ________ (metal objects), some materials _________ radiation (glasses and plates) and some materials __________ radiation (food containing water, fat or sugar).

33. P2.6 Mobile phones and health Extension questions: 1: Explain how do mobile phones work and how are microwaves used to transfer information form the mobile to the network ? 2: Explain why people think mobile phones are bad for your health ? 3: Why are phone masts kept away from people ? 4: How much radiation can a) a mobile phone produce and b) a phone mast produce ? 5: Are people right to be concerned about the effects of phone use particularly on children who have thinner skulls ? Know this: a: Know that mobile phones and their networks use microwave radiation. b: Know how to quantify the risk form using mobile phones. Friday 21 October 2011 Introduction: Mobile phones receive and send messages using microwaves. Information is carried by microwaves form the phone mast to the mobile phone. Information is exchanged on the network using patterns in the microwave radiation. Mobile phones produce about ¼ watt of radiation in communicating with the phone mast. This radiation can also be absorbed through the skull and into your brain where it can produce a heating effect after 15 minutes. Phone masts are kept at a safe distance away from people this is due to the fact that they can produce 100 watt radiation, which I 400 times more powerful than the radiation used by mobile phones.

34. P2.6 a Look at the photograph and information and answer all the questions: The effect of mobile phone radiation on human health is the subject of recent interest, as a result of the enormous increase in mobile phone use. Mobile phones use electro-magnetic radiation in the microwave range, and researchers believe this could be harmful to human health. Other digital wireless systems, such as data communication networks produce similar radiation s Explain why we may not know the full risk or effects on health form using phones for many years ? Explain why people are more concerned about living close to a mobile phone mast when compared to using mobiles daily ? Do you think the government should warn people of the possible effects on human health when using mobile phones ? The heating effect caused by mobile phones before phone use After 15 mins phone use 33.5 o C 32.0 o C 30.0 o C 29.0 o C 27.5 o C 25.5 o C 23.5 o C Key concepts

35. P2.6 b Look at the photograph and information and answer all the questions: Against mobile phones For mobile phones At present scientific research suggests that microwave radiation produced by mobile phones is unlikely to harm people. But the precautionary principle suggests that sometimes the cost of an activity may outweigh the benefit and perhaps the health problems of mobile phones may take some time to develop. What types of evidence can we use when making a scientific decision to the question ‘are mobile phones safe to use’ ? What can we do to use mobile phones more safely ? What is the difference between an actual risk and a perceived risk ? Mobile phones linked to brain tumours in the USA Exposure to low powered microwave radiation causes heating effect in children report finds Parents report increase hyperactivity in children who use mobile phones Rats exposed to microwave radiation show changes in brain function Finding from 8 different European countries show no link between mobile phone use and an increased risk of developing brain cancer Mobile phone industry report no risk to using their products No significant change in brain tumour rates over the last 100 years Key concepts

36. P2.6 Plenary Lesson summary: Decide whether the following statements are true or false : False True False True False True absorbed microwaves patterns information About 40 million people in the UK now own and use a phone. Worldwide it is estimated that 2.5 to 3 billion people use mobiles. All mobiles use microwave radiation which in substances containing water can produce a heating effect. The brain contains large amounts of water and thermal imaging has shown a warming effect from using a phone for just 15 minutes. Whether this heating effect increase the risk of developing a brain tumour only time and scientific research will show How Science Works: Friday 21 October 2011 Research into dealing with risk and assessing risk within science. Preparing for the next lesson: 3: Radiation can be absorbed by the body ? 2: Phone masts don’t produce strong radiation ? 1: Mobile phones use microwave radiation ? Mobile phones receive messages via ________from a phone mast and send microwaves back, ________ in the radiation carry________. Mobiles phones produce ¼ watt of radiation which is then _______ into your skull.