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Sensors!
Author: Eeva Hedefine Disciplines: Section 1: All within middle grades 5-8; Sections 1-3: Life Science Introduction Associated Maine Learning Results
Section 1: Sensors in Our World Introduction
Required Equipment
Procedure
Expected results Students will learn about the great number of sensors that surround them and which they make use of every day. This will help them to better relate to technology and bring it down to a simpler level that they can understand. By providing many common examples of sensors, students can better understand what a sensor is and how it works. They will come to appreciate how much technology improves and enhances our lives. Troubleshooting N/A References
Slide 1: Sensors in Our World We are surrounded by sensors throughout each day of our life. Sensors can be found in all kinds of common everyday objects we may have never considered. From the alarm clock that wakes us up in the morning to the stove that cooks our breakfast to the bus that takes us to school and back again. Sensors can be found in all these objects and many objects contain more than one sensor, even many sensors! Slide 2: What is a sensor? A sensor is simply a device that receives and responds to a signal or stimulus. The stimulus may include heat, light, sound, pressure, magnetism, or motion. The device itself may be fairly simple, such as a thermometer, or it may be something more complex, such as sensors found in the electronics of a DVD player. Slide 3: Common Household Objects Containing Sensors If we look around our home, we can find sensors almost everywhere we turn. Here is a list of 30 objects containing one or more sensors. Did you ever think of these objects as having sensors in them? Can you think of any other objects in your home that contain sensors? Slide 4: Automobiles Contain Hundreds of Sensors! Newer automobiles contain hundreds of sensors. Did you ever think there were that many sensors in your vehicle? As auto technology advances even more, no doubt the number of sensors in an automobile will grow as well. Can you think of any other sensors in your family’s vehicle? Slide 5: How Stores Use Sensors (1st of 2 slides) “Loyalty” cards such as the Shaws card are scanned with a sensor, as you’ve probably noticed at the checkout counter. Since the cards are linked to a person’s name and account information, when your parents use the card, the store is able to collect information about their purchases for marketing purposes. If they can learn what types of items your family and other families are interested in, and how often they buy those items, it will help a store to know which items to stock. It will also allow stores, and others they may share that information with, to target a customer with specific advertisements or coupons. This can be a good thing if you want to receive special offers tailored to your buying habits, or not so great if you don’t like to receive a bunch of junk mail! Credit card companies can also collect this type of information from your parents’ credit card purchases. Stores have begun introducing high tech shopping carts. Some carts contain sensors that can detect when someone is trying to remove a shopping cart from the store’s property. This causes the cart wheels to lock up, so that the cart cannot be pushed outside the parking lot boundaries. Other stores are experimenting with putting computers on shopping carts. By swiping a loyalty card, the cart computer can know the identity of the shopper and can access stored records of a shopper’s past buying habits. By knowing what types of items the shopper usually buys, it can offer special coupons or prices for those kinds of items, perhaps as the shopper is passing the aisle they are contained in. This will be possible through locating technology within the cart, providing the location of the cart as it moves through the store. If you want to know where a particular item, such as a jar of spaghetti sauce or a bag of potato chips, is located, you can ask the computer. Slide 6: How Stores Use Sensors (2nd of two slides) RFID or Radio Frequency Identification tags have been used for a number of years in the theft prevention tags attached to items such as clothing in department stores. These tags are often bulky, but RFID technology is advancing to the point that tags are now small enough to place in clothing, such as pictured in the bottom center and right of the slide. RFID tags may also be placed into “loyalty cards” such as the METRO Extra Future Card from a store in Rheinberg, Germany. The image in the center of the slide shows an antenna attached to a microchip, which is contained within the loyalty card pictured on the right. These RFID-embedded cards can identify the shopper and his/her location in the store. Each tag contains a unique ID number that can be linked to a particular shopper. Since RFID technology doesn’t require scanning of the card, the unique ID can be read by what’s known as an RIFD reader, operating and communicating through radio signals. So without even being aware any data collection is taking place, shoppers may be broadcasting information about themselves to the readers located around the store. This information could include what items customers stop to look at or decide to buy. The tag’s unique ID can be linked to other stored personal information, such as past purchases. RFID readers can also be placed into shelving to form “smart shelves.” These readers can communicate with the RFID tags in product packaging, such as in a box of cereal or a carton of milk, providing information for inventory purposes. The readers can alert the store when the stock of items on the shelf is getting low and needs to be replenished. In the future, RFID tags may be placed in all kinds of consumer items, such as clothing and food or other product packaging. With RFID technology, tracking of a tag’s location, and if you are wearing a tag, your location, is possible through RFID readers located within a store. The question is - Will these tags allow you to be tracked once you leave the store? What if there was a pervasive environment of RFID readers dispersed throughout a city? What kinds of information could they collect? Do you think this is a good idea or not? Slide 7: Tsunami Sensors In addition to the sensors we may come across everyday, sensors are being deployed in all kinds of areas in order to provide safety and warning systems. Recent events have shown the importance of early tsunami detection. In order to provide enhanced detection and warning of tsunamis, NOAA (National Oceanic and Atmospheric Administration) is proposing implementation of a buoy system known as Deep-ocean Assessment and Reporting of Tsunamis (DART). The image on the left of the slide shows the buoy design, including some of the types of sensors that will be used in this system, such as a sensor to determine the pressure on the ocean floor A GPS system is also included to provide a communication link through which the captured data may be transmitted, therefore enabling a warning to be given. NOAA plans to deploy 32 new DART buoys, which should be fully operational by mid-2007. Through this system the coasts of the Unites States will be provided with almost 100% tsunami detection capabilities, and these capabilities will be expanded throughout the Pacific and Caribbean basins as well. The image on the right side of the slide depicts the locations of both in-place and proposed Deep-ocean Assessment and Reporting of Tsunamis (DART) buoys. Slide 8: Sensing Black Holes Sensors are also be utilized in the exploration of outer space. One such area is in the detection of black holes. The top left image depicts the Hubble Space Telescope, which provided the image below it of a supermassive black hole located in another galaxy! The bottom right image is a drawing of the Chandra X-ray Observatory, which detected this x-ray flare (top left image) within Sagittarius A of our own galaxy. This device incorporates all kinds of sensors, such as those in the high resolution camera and the imaging spectrometer, an instrument that measures the wavelengths of light. The x-ray flare is evidence of a black hole. Gaseous matter is pulled into a black hole and is heated as it spirals inward. Some of this matter is expelled in jets of high-energy particles, which can be detected as x-rays with an imaging spectrometer. So from this presentation we can see that sensors are a big part of our lives, from the seemingly ordinary objects we come across every day to the extraordinary instruments being used in space exploration. As you go through the rest of the day - at school, traveling home, and later in your home - think about the objects around you and which ones contain sensors. See how many you can find by the end of the day. Sensors Pre/Post Test (Downloadable PDF format)
1. Which of the following is true? (A stimulus is something that causes a response or an action.) a. A sensor is a device that receives and responds to a signal or stimulus. 2. Which of these objects contains a sensor? a. Lamp 3. How many objects in a home contain a sensor? a. 0 4. How many sensors are found in an automobile? a. 1
Introduction Associated Maine Learning Results
Station 1: Sense of Taste
Procedure Troubleshooting References “Tasty Buds” lab available at http://faculty.washington.edu/chudler/chtaste.html Location of the taste buds on the tongue available at http://www.sedl.org/scimath/pasopartners/senses/lesson6a1.html Additional resources for human senses material and activities: http://www.sedl.org/scimath/pasopartners/senses/welcome.html
Required Equipment
Procedure Note: This is a condensed version of the “You’ve Gotta Lotta Nerve” lab and is only meant to outline the lab. For the full lab, including questions for analysis, see the citation for the lab listed in the References section. The assignment is to find the areas (nerve receptors) on the back of the hand that are most sensitive to different types of stimuli – pressure, heat, and cold.
Expected results Troubleshooting References “You’ve Gotta Lotta Nerve”
Lab
Station 3: Sight—Demonstrating Blind Spots and Testing for Color Blindness Required Equipment
Procedure
Note: Prior to this activity, the teacher may want to discuss the causes and effects of color blindness. Expected results Troubleshooting References
Required Equipment
Procedure
Expected results Troubleshooting References Pasco Scientific “Extremity Remedy” Lab
Section 3: Sensors Enhancing Our Senses Introduction Associated Maine Learning Results
Required Equipment
Procedure 1. Sight - photoreceptors (rods and cones) in our retinas detect light, convert the light energy to electrical signals which are transmitted to the brain through the ganglion cells coming together to form the optic nerve. The brain decodes the signals and interprets them as images. 2. Smell – receptors found in cilia (hair like fibers)
of olfactory neurons in the nose detect odors and send a signal to
the brain, which then interprets the signal as a specific odor. 3. Nerve receptors in our skin - From the lab activity testing
the nerve receptors on back of your hand with hot/cold water and pressure,
we discovered different areas of our skin are more sensitive than
others, due to the presence of more nerve receptors. Ask: What are some simple devices/technology that we use to enhance our senses? Examples: Eyeglasses, hearing aides. Discuss how sensors enhance our senses and how they operate in the same ways as our own senses. 1. Enhancement to sight through retinal implants: Students can either read through slides or go ahead to the page on “How it Works.” Retinal implants (silicon chip eye implants that can stimulate damaged rods and cones) can help restore vision due to blindness from 2 types of eye diseases: a. Macular degeneration – An age-related, degenerative disease, causing loss of rods and cones, leading to blindness. Vision loss is in the center of the visual field, making reading difficult, but sparing peripheral vision. b. Retinitis pigmentosa – Hereditary, with slow progression of rod and cone loss. Vision loss begins in the periphery and expands to include more. These diseases damage the rods and cones, whose function is to convert incoming light into neural (electrical) signals. The implantable chip stimulates the ganglion cells to send nerve signals to the brain. As the students look at the retinal implant diagram on the “How it Works” page, discuss how the implant device functions. The diagram shows a camera located on a pair of eyeglasses, which captures an image and encodes it into an electrical signal. A laser beam transmits the signal through the pupil to a receiver in the eye, like a television signal sent on a cable. The image information is decoded and electrical pulses are transmitted to ganglion cells. These electrical signals go through the optic nerve to the brain, where they are decoded, producing an image. Then continue through the slide program or go ahead to the “Future Developments” page and then discuss the image of future retinal implants. So far, implanted patients can only see lights or outlines of objects,
but there is hope to provide complex/perfect images in the future,
through permanent rather than temporary implants. This web site discusses research being conducted regarding “mapping live camera images into sound,” for those who went blind early or were blind from birth. Blind users learn to decode complex sounds as meaningful vision.
This web site has a diagram of how the system to record monkey brain
signals works and a image of a monkey used in the research. This next web site provides additional information on how this research
was conducted and the results. While viewing http://news.bbc.co.uk/2/hi/sci/tech/1025471.stm, discuss this research with the students. Monkeys in this study had 96 electrodes implanted 1mm deep within the area of their brain involved with motor function. Researchers recorded the brain (bioelectrical) activity as a monkey moved his arm to reach for objects or food, and then as he moved a mechanical arm pictured on a computer screen with a joystick. A computer linked to the implanted electrodes processed the signals and analyzed patterns as the monkey performed these various tasks. The signals and patterns were used to move a robotic arm 600 miles away, by sending signals over the Internet. The computer figured out certain patterns specified commands, such as to "reach" or "grasp." The computer “read” the monkey’s mind, decoded the brain signals and sent instructions to a robotic arm. Researchers then unplugged the joystick and the monkey controlled the robot through its thoughts. In the future, wireless connections will be used for linking to a computer. This technology will allow
3. Electronic Nose NASA Space Station This web site discusses how NASA will use an electronic nose. Electronic noses can:
Electronic noses are more sensitive than human noses. They can detect an electronic change of 1 ppm. Briefly discuss how the sensor array in the middle of the web page works. A sensor array (group of sensors) of 16 polymer films is used. Polymers are compounds spread as thin films or layers over a sensor. These films conduct electricity. When the molecules (vapors) of a substance are absorbed by the films, the films expand slightly, changing the amount of electricity conducted. Each film reacts differently, so with 16 films, a distinct pattern can be obtained for each compound needing to be detected. In the future an automatic response or “intelligent safety system” can be set up, allowing the system to warn the crew of a fire, turn on fans to redirect air flow, turn on filters, seal off an area or other perform other tasks in quick response to a safety threat. Ask Students: What types of applications can you think of for an electronic nose? Here are several web sites discussing applications: Applications
Expected results Troubleshooting References
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