iSTEM STAGE 5 Aeronautics – Gliders
Introduction to Glider
3. Hang Gliding Ground Instruction 2.40 mins
Surviving Toxicity using Knowledge of Solubility
Many people today live active and productive lives because faulty parts of body can be replaced by new materials and new devices. These materials and devices can have a significant impact on a person’s quality of life and the length of life.
Bionics is the use of electronic and mechanical devices that copy the behaviour of parts of the human body. Through scientific knowledge gained on the biological systems, engineering systems, and artificial intelligence, scientists continue to extend their understanding of biological principles to solve engineering problems.
Prothesis Is an artificial body part (replacing or supporting a natural part of the body eg – teeth, eye, bone)
By studying the structure of living things, chemists learn about arrangement of molecules and use this knowledge to produce synthetic materials that are hard or soft, stiff or elastic, just like the real thing. These special materials – able to function with living tissue, with minimal ejection by the body – are called biomaterials.
Engineers make devices from biomaterials and designed to perform specific functions in the body are generally referred to as biomedical devices or implants.
Scientists use the principles of engineering coupled with a knowledge of the functioning of organs and body systems for development of therapeutic devices such as artificial body parts and systems such as artificial blood vessels, pacemakers, dialysis equipment and artificial limbs.
Many devices currently used in the human body as artificial organs and prosthetic devices.
An organ is a specialised structure (e.g. heart, kidney, limb, leaf, flower) in an animal or a plant that can perform some specialized function. These varied parts (organs) sometimes become defective and must be replaced by an artificial organ or a prosthetic device. These replacement devices are constructed of natural or synthetic polymeric materials. Such biomaterials must exhibit good compatibility with the blood and the body fluids and tissues with which they come into contact. Artificial device must closely duplicate the function of the natural organ. In practice, these artificial devices are constructed from a wide variety of materials such as metals, ceramics (including glass and carbon), natural tissues (actually polymeric in nature), and synthetic polymers. Partly due to the wider range of properties available, most of these artificial devices are constructed wholely or partly from natural or synthetic polymers. Obviously the same polymer could not be used for all possible artificial organs or prosthetic devices. Rather, the material to be used must be matched to the specific use requirements. Artificial organs can conveniently be classed into four groups: (I) Bone/Joint Replacements (e.g. hip, knee, finger, total limb), (II) Skin/Soft Tissue Replacements (e.g. skin, breast, muscle), (III) Internal Organs (e.g. heart, kidney, blood vessels, liver, pancreas), and (IV) Sensory Organs (e.g. eye, ear).
|Body Part||Biomaterial used or
Biomedical device used
|Reasons for use
of artificial device
|Head, Limbs, (Skeleton)||Pins, screws and plates||Broken, crushed bone|
|Knee, Hip, Elbow, Knuckles||Artificial joints||Degeneration, damaged|
|Ears||Cochlear implants||Replace damaged inner ear|
|Heart||Pacemakers||Irregular heart beat|
|Heart, arteries||Artificial valves||Valves not functioning correctly|
|Teeth||Crowns, dentures||Tooth decay, Broken teeth|
|Eyes||Lenses||Damage caused by cataracts|
|Arms. Legs||Prosthetic limbs||Loss of limb by disease, accident|
Star formation – What you need to know……
WORKING SCIENTIFICALLY: ERRORS, Fair Test etc.
These are values in a set of results which are judged not to be part of the variation caused by random uncertainty.
Question 1: Matthew records the current in a resistor for a certain voltage and takes repeat readings, some of which are shown below:
|Resistance (Ω)||current (A)|
Question 2: Simon measures the mass of a mug as being 250 g, but its true value is actually 260 g. The difference is a measurement error.
(True value is the value that would be obtained in an ideal measurement. An ideal measurement is one that would have no errors at all)
Calculate the percentage error in Simon’s measurement.
The interval within which the true value can be expected to lie, with a given level of confidence or probability, e.g. “the temperature is 20°C ± 2°C, at a level of confidence of 95%.”
The symbol ± is called “plus or minus”, and in the example above means “plus or minus 2°C” – i.e. the temperature is most likely to be between 18°C and 22°C.
The “level of confidence” expresses how certain the scientists are of their claim that the temperature is in the range 18—22°C.
Question 3:(a) State the mean and the uncertainty for the following data:
33, 36, 28, 37, 29, 27, 30, 31
Question 4: In conducting an experiment comparing the speed of sound to the air temperature, Amasha’s thermometer has units of 1 o C and you have found the air temperature to be 20 o C. Calculate
These cause readings to be spread about the true value, due to results varying in an unpredictable way from one measurement to the next.
Random errors are present when any measurement is made, and cannot be corrected. The effect of random errors can be reduced by making more measurements and calculating a new mean.
Random errors may be caused by human error, a faulty technique in taking the measurements, or by faulty equipment.
Question 5: Fawad and Andrew are both timing a very fast pendulum with a stopwatch. Andrew can’t count the swings accurately as it is just too fast to keep up – this introduces a random error in his readings as he may think he has counted 20 swings when in fact it was 21.
Fawad doesn’t use the stopwatch very well. Although he starts it fairly accurately, he panics when having to stop it and is either too early or late. This is a random human error.
Suggest how Fawad and Andrew can improve the reliability of their data. Explain your answer.
Question 6: Matthew records the current in a resistor for a certain voltage and takes repeat readings, some of which are shown below:
|Resistance (Ω)||current (A)|
These cause readings to differ from the true value by a consistent amount each time a measurement is made.
Sources of systematic error can include the environment, methods of observation or instruments used.
Systematic errors cannot be dealt with by simple repeats. If a systematic error is suspected, the data collection should be repeated using a different technique or a different set of equipment, and the results compared.
e.g. A systematic error occurs when using a wrongly calibrated instrument.
E.g. Ashley’s pendulum timing experiment was made worse by the fact that she also began counting at ‘1’ not ‘0’. So all her times, in addition to random in her counting, were also short of one full swing each making her calculated times all smaller than the ‘true values’.
7 FAIR TEST
A fair test is one in which only the independent variable has been allowed to affect the dependent variable.
A fair test can usually be achieved by keeping all other variable constant.
Swee Yong and Pavan are investigating how the electrical resistance of wires changes with length. Unfortunately both of them let the current get too high for shorter wires, which dramatically increases their temperature. Since temperature affects resistance (in addition to the length), it is not a fair test.