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Sciencegirl Adventures!
May 31, 2013
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Fun Science, Uncategorized | Tagged: children's science, Key stage 1, key stage 2, key stage science, kids science, primary school science., science education | 
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Posted by Jenny Gawley
The Biomechanical Breakdown of Bolt’s Race
August 8, 2012
Usain Bolt could run the 100m dash in 9.44s, given the right legal conditions, claims Cambridge mathematician, Professor John Barrow…if only he could get off the starting blocks a little bit quicker.
The Acceleration Phase (0-30m)
Unfortunately for Bolt, the sprint start and the acceleration phase account for 64% of the total result in the 100m dash. This creates a major disadvantage for taller sprinters, who are often poor starters.
Bolt’s reaction times are generally much slower than the 0.1s allowed and physics noticeably hampers him during the acceleration phase.
The Physics:
The acceleration is proportional to the force produced when pushing off the blocks but there is an inverse relationship between acceleration and body mass.
This means that height is a disadvantage because the force also has to overcome the drag produced by a bigger body.
Sprinters with well-developed, strong muscles attached to shorter limbs promote more rapid movements and a greater force, which gives them an initial advantage.
Maximum Velocity Phase (30-60m)
During this phase the runners are upright, well away from the blocks and are attempting to reach their top speed, which is achieved through a combination of stride length and stride rate.
This is where a taller sprinter has the potential to catch up – long limbs and good flexibility alone achieve half of the speed formula.
Bolt’s gangly limbs suddenly become an advantage, meaning he can reach 44km/h during this phase and can pull ahead, despite his poor start.
It also explains why Bolt does not achieve the same kind of success in the 60m dash as he does at longer sprint races: he is still catching up at the beginning of this phase!
Speed Maintenance Phase (60-100m)
The final phase is all about speed maintenance and Bolt himself has stated that if he is ahead at 60m, the other contenders simply don’t stand a chance.
Bolt is able to maintain his pace exceptionally well and in the Olympic 100m final Bolt completed the race in just 41 steps, compared to Blake’s 46 steps.
In the 200m final Bolt’s poor start will be even less of a factor…Thursday 9th at 8.55pm BBC1
1 Comment | Fun Science, Human Biology, Olympic Science, Physics | Tagged: 100m final, 100m world record, 200m final, 60m dash, acceleration phase, Bolt, drag forces, London 2012, london olympics, Olympic final, professor john barrow, reaction times, speed maintenance, sprint start, tall sprinters, Usain Bolt | Permalink
Posted by Jenny Gawley
What do frogs and archers have in common?
July 31, 2012
Elastic energy! For those who’ve forgotten their school physics –or never paid attention!- elastic energy is potential mechanical energy that can be stored when work is performed to stretch or compress an object or physical system.
How does the frog do it?
As a frog prepares to leap, the calf muscle shortens and pulls on the tendon, which is wrapped tightly around the ankle bone. After a fraction of a second the calf muscle stops moving and the energy is fully loaded onto the stretched tendon. When the frog jumps, the elastic energy is released like a catapult, propelling the frog forward!
Frog fact: Frogs can jump amazing distances -in some cases up to 50 times their body length, which is the equivalent to a human jumping the length of a football field from a standing position!
How does the archer do it?
The archer creates the elastic potential by drawing the bowstring back, changing the configuration of the bow. The force is stored in the distorted shape until the archer decides to release the bowstring, just as the energy is stored in the frog’s tendon until it decides to leap! The arrow is then propelled at a much greater speed than muscles alone could achieve, projecting the arrow much further.
Archer fact: Archers competing in the London Olympics will be aiming their bows at targets approximately 70m away, a distance impossible to reach if they relied on the kinetic energy of the muscles.
Leave a Comment » | Fun Science, Olympic Science, Physics | Tagged: archers, archery, elastic tension, elastice energy, frogs, London 2012, mechanical energy, olympics, potential energy | Permalink
Posted by Jenny Gawley
Blood Doping with EPO
July 11, 2012Blood doping usually involves the hormone growth factor, erythropoietin (EPO), which stimulates red blood cell formation in the bone marrow. Although it occurs naturally in the body, DNA technology can be used to produce EPO in the lab and then injected under the skin.
Why are red blood cells so important?
Red blood cells, or more specifically the haemoglobin (Hb) protein of the red blood cell, binds oxygen in the lungs and carries it to muscles throughout the body. One of the major limiting factors in endurance exercise is oxygen delivery to the working muscles. The more oxygen carrying capacity an athlete has, the better the athlete’s endurance.
How do scientists detect the use of EPO?
The volume of the red cell population in the blood is known as the haematocrit (HCT) and is normally between 41-50% in men, and 36-44% in women. Haemoglobin concentration can also be measured and should fall between 14-17g/dL in men, and 12-15g/dL in women. If blood tests detect high HCT or Hb values, it can indicate the use of EPO. Occasionally, athletes have naturally high HCT or Hb measurements, so testing over extended time periods is essential to determine exceptional values for the individual athlete.
The dangers of EPO doping
Excessive use of EPO can make blood more viscous; putting a strain on the heart muscles and has in many cases led to heart failure. The sport probably most associated with EPO is cycling but many endurance sports including rowing, distance running, triathlons and horseracing have had their fair share of scandal.
Leave a Comment » | Health, Human Biology, Olympic Science | Tagged: blood doping, endurance exercise, EPO, erythropoietin, haematocrit, Haemoglobin, HCT, hormone growth factor, red blood cell | Permalink
Posted by Jenny Gawley
Olympics Countdown: Why the dopers are heading for disaster
June 28, 2012What is drug doping?
The International Olympic committee (IOC) define drug doping as the use of any method or substance that might harm the athlete, in a quest to gain an unfair advantage over their fellow competitors.
What methods are used?
Typically, cheats use performance enhancing drugs or blood doping. The performance enhancing drugs are usually stimulants, which increase alertness and physical activity, or steroids, which increase muscle mass. Blood doping involves undergoing a blood transfusion in order to acquire a higher red blood cell count, allowing extra oxygen to be carried to the muscles.
How are drug cheats caught?
Two urine samples are obtained from athletes and analysed using gas chromatography (which separates the contents of the sample) and mass spectrometry (which provides the exact molecular specification of the compound). If a banned substance is identified in both samples a positive result is declared.
Blood testing is also used to detect banned substances and to build a ‘blood profile’ over time for an individual athlete. This is used to determine average readings for the athlete and any significant changes that could indicate blood doping.
What’s so special about London 2012?
For the first time, a private sponsor -GlaxoSmithKline (GSK)- will be providing what are considered to be the most hi-tech laboratory facilities in Olympic history, at a cost of more than $30 million. GSK will test over 6,250 samples of blood and urine during the London Olympics, compared to 4,500 in Beijing, and 150 scientists will be on duty around the clock.
London 2012 could be the cleanest games ever. Keep Britain Tidy!
Leave a Comment » | Human Biology, Olympic Science, Technology | Tagged: blood doping, blood transfusion, drug doping, gas chromatography, GlaxoSmithKline, International Olympics committee, London 2012, london olympics, mass spectrometry, performance enhancing drugs, steriods | Permalink
Posted by Jenny Gawley
Legionnaires’ Disease
June 8, 2012
Legionella pneumophila is a gram negative bacterium (this refers to the characteristics of the bacterial cell wall and is important in determining which antibiotics will be most useful to fight it) and is the causative agent in Legionnaires’ disease.
Once the bacterium has entered the body it invades cells called macrophages. Macrophages are cells of the immune system which normally scavenge cells debris and engulf invading pathogens so they can be destroyed by other cells.
The Legionella pneumophila bacterium, however, is able to replicate itself inside the macrophage instead of being destroyed.
The bacterium is transmitted via tiny airborne droplets that are released when water is disturbed and are then inhaled into the lungs.
The most common sources are cooling towers (suspected to be the case in the current Scottish outbreak), ice machines, hot-tubs, showers, air conditioning systems and any complex potable water system or cooling system.
Once infection has taken hold (between 2-10 days), the immune response initially causes fever, chills, muscle aches, headaches and a cough, similar to flu symptoms.
More serious consequences of infection include kidney and liver damage. Middle aged, elderly people, smokers, and patients with chronic lung conditions have an elevated risk of contracting the disease.
Antibiotics that have good intercellular penetration are most effective against the bacterium, such as tetracyclines or erythromycin.
2 Comments | Health, Human Biology, Science Issues | Tagged: edinburgh legionnaires, legionella pneumophila, legionnaires' disease, macropahges | Permalink
Posted by Jenny Gawley
How Your Ears Can Predict Your Chances of a Heart Attack
April 12, 2012A study to be published in next month’s American Journal of Cardiology has confirmed that earlobe creases are associated with coronary artery disease. This research upholds the findings of several other studies, including a 2006 Swedish study, which showed that earlobe creases as a marker for heart disease had a positive predictive value of 80% in people under 40 years old.
The marker is a diagonal crease running from the opening of the ear to the outside tip of the earlobe and is not associated with sleeping position or the wearing of earrings. Having the marker is a higher risk factor than having a family history of heart problems, diabetes or even smoking.
It is not fully understood what causes the crease but it’s probable that it indicates premature aging. The soft tissue of the earlobe contains tiny blood vessels called arterioles and degeneration of the tissue surrounding the arterioles causes the wrinkle to appear. This is similar to the type of change associated with the hardening of the arteries and so is perhaps an insight into what is happening inside the body.
Certain retinal disorders have long been known to correlate with heart disease incidence and now it seems the earlobes are another window to the heart. The association between the earlobe marker and the incidence of heart disease is so strong that it could be a significant independent predictor of any coronary artery disease, according to the authors of the study.
I bet you go and look in the mirror right now…
2 Comments | Health, Human Biology | Tagged: arteries, coronary heart disease, ear lobe, ear lobe crease, heart, heart attack, heart disease | Permalink
Posted by Jenny Gawley
Sipping v Quaffing: how to reap the health benefits of red wine
April 11, 2012For the last few decades the mainstream press have extolled the virtues of moderate red wine consumption, particularly the possible cardioprotective benefits of resveratrol, found in the skin of red grapes. Sales of red wine have increased dramatically as the masses have embraced the notion of ‘healthy’ drinking but it seems only those truly appreciating the wine reap the cardioprotective benefits.
Once resveratrol reaches the gut it is rapidly converted into another compound called piceatannol and so does not enter the bloodstream. Sipping wine slowly, however, allows the resveratrol to be absorbed intact via the mucous membranes in the mouth, which greatly increases resveratrol blood levels. So perhaps the quaffers should pay heed to the wine connoisseur and pause to appreciate the taste and mouth-feel attributes of the wine, improving their health all the while.
Although many wine drinkers already delight in savouring a good red on the palate, it’s not all bad news for the quaffers. New research by scientists at Purdue University, Indiana, indicates that piceatannol, the breakdown product of resveratrol, might have its own health benefits. The study, published in this week’s issue of The Journal of Biological Chemistry, reports that piceatannol prevents fat cells from maturing, thereby arresting fat cell formation. Although still in its preliminary stages it has potential implications for combating rising obesity levels and preventing weight gain.
As noteworthy as the research is, it presents a serious dilemma to the red wine drinker: sip to save your heart or quaff to quell the weight? Sciencegirl thinks it’s probably wise to have two glasses on the go, one for sipping and one for quaffing. Just to be sure, of course.
Leave a Comment » | Adult Science, Health, Human Biology | Tagged: cardioprotective, heart, obesity, piceatannol, quaffing, red wine, resveratrol, sipping, weight loss | Permalink
Posted by Jenny Gawley
Striking Back At Stroke
April 3, 2012An estimated 150,000 people in the UK have a stroke each year and more than a third die within a week. For those who do survive, rehabilitation is a lengthy process and stroke patients occupy up to 25% of long-term hospital beds.
Stroke victims are often left with impaired communication, known as aphasia. The most common problem is anomia, a condition in which the patient is unable to find the right word to say (a very severe form of everyone’s ‘tip of the tongue’ experiences). Traditional therapy to treat anomia is extensive and requires intervention over a long time period to be successful. However, a new brain zapping therapy trialled by neuroscientists at University College, London has enabled patients to make a startling recovery, compared to patients undergoing traditional therapy.
Whilst patients were undergoing vocabulary training neuroscientist Jenny Crinion and her colleagues applied transcranial direct current stimulation to the left side of the brain in the area related to speech production. After six weeks the patients had improved by an astonishing 92%, compared to just 56% in patients who had received the vocabulary training without the stimulation therapy. The stimulation is thought to stimulate nerve cell activity in Broca’s area, which is the part of the brain devoted to speech comprehension and production.
For more information about stroke and how to recognise the signs click here.
Leave a Comment » | Health, Human Biology | Tagged: anomia, aphasia, brain stimulation, brain zapping, stroke, tip of the tongue | Permalink
Posted by Jenny Gawley
How To Change Your Skin Colour and Become More Attractive in Six Weeks.
March 17, 2012If you need another motivational tool to inspire you to eat your five a day, look no further. Scientists at St Andrews University, Scotland have found that consuming 3.3 portions per day of fruit and vegetables containing high levels of carotenoids for six weeks increases attractiveness.
Carotenoids are pigments commonly found in brightly coloured fruits and vegetables such as carrots, peppers and tomatoes and their antioxidant properties are well documented. However, carotenoids can accrue in the skin and their accumulation imparts colour of a yellowish tone, which is perceived as more attractive. When participants are able to digitally manipulate the skin colour of Asian, African and Caucasian face stimuli to their liking, yellowness is consistently increased both for the participants own ethnicity and other ethnicity faces.
At the end of the six week study individual differences in carotenoid consumption caused noticeable variation in skin tone, which was measured using spectral reflectance analysis. The minimum colour change needed for more attractive skin colouration can be achieved by eating less than four portions a day of carotenoid loaded fruit and vegetables. Looks like the beauty counters are going to be losing business to the greengrocers!
Leave a Comment » | Fun Science, Human Biology | Tagged: antioxidant, beauty, carotenoids, race, skin color | Permalink
Posted by Jenny Gawley
