HOW ORGANISMS SENSE ENERGY

Sensors and Detectors

OBJECTIVE TODAY:Our objective today will be to answer the following questions:How do we sense and detect energy?What are sensors and detectors?What sensors or detectors are used in science?

What sensors are used in other living things?

SENSORS AND DETECTORS

A sensor or a detector is a device that responds to a stimulus, (energy) such as heat, light, chemical or kinetic. It then generates a signal that can be measured or interpreted. Humans and all other organisms have sensors that can detect the energy around them. This ability may be inherent or has become an adaptation over time.Detectors are used in physical science to respond to energy signals and forces. They are not only necessary for living organisms to survive, but help us use and enhance our senses to energy.

DETECTORS IN SCIENCEScientists have invented various types of sensors to detect energy forms. For example, a smoke detector in your home will set off an alarm when the energy from smoke or heat reaches its detection device. The microphone on your tape recorder detects the energy from sound waves and creates an electric signal that records the sound. Here are several other examples:Solar cells and photographic film detect light.Microphones detect sound.Thermometers sense the change in heat or temperature.Pressure gauges detect touch.Scales detect and measure the effect of gravity.There are many devices that detect various chemicals and even odors.A magnetometer detects magnetic fields.An electric meter detects electricity.A Geiger counter detects atomic radiation.Seismograph/Seismometer: tool that measures the amount of ground movement (kinetic energy) in earthquakes.

HOW ORGANISMS SENSE ENERGY?

Humans and animals can detect various forms of energy through their sensors and detectors:Eye detects light energyEar detects sound energySkin detects both physical pressure and heat energyNose detects certain smells due to chemical reactionsTongue detects other chemical reactions when food is broken down.Inner ear detects gravitySome animals can also detect electrical signals and magnetic fields.

HOW OUR EYES SENSE LIGHT ENERGY?Your eyes are at work from the moment you wake up to the moment you close them to go to sleep. They take in tons of information about the world around you — shapes, colors, movements, and more. Then they send the information to your brain for processing so the brain knows what's going on outside of your body.

How the eye works:

http://kidshealth.org/kid/htbw/eyes-movie.html

DETECTORS IN SCIENCE THAT HELP US

Glasses: improve our ways in which we sense light energy.

Glasses are used to focus the amount of light that reaches our cornea.

Most vision problems occur when the eye cannot focus the image onto the retina. Here are a few of the most common problems:Myopia (nearsightedness) occurs when a distant object looks blurred

because the image comes into focus before it reaches the retina. Myopia can be corrected with a minus lens, which moves the focus farther back.

Hyperopia (farsightedness) occurs when a close object looks blurred because the image doesn't come into focus before it gets to the retina. Hyperopia, which can also occur as we age, can be corrected with a plus lens. Bifocal lenses, which have a small plus segment, can help a farsighted person read or do close work, such as sewing.

Astigmatism is caused by a distortion that results in a second focal point. It can be corrected with a cylinder curve.

Placing the correct type and power of lens in front of the eye will adjust the focal point to compensate for the eye's inability to focus the image on the retina.

ORGANISMS AND LIGHT ENERGY

Eagles have eyeballs that are 35mm (compared to human eye ball that is 24mm)

This allows Eagles of see 2.0 to 3.6 times better than that of a human.

Falcons can see a 10cm object from a distance of 1.5 km away.

Flies have 3,000 lenses in each eye. Allowing it to process much faster than a human’s eye.

HOW OUR EARS SENSE SOUND ENERGY?Your ears are in charge of collecting sounds, processing them, and sending sound signals to your brain. And that's not all — your ears also help you keep your balance. So if you bend over to pick up your cat, you won't fall down — or even worse — fall on your cat. Meow!

How the ear works:

http://kidshealth.org/kid/htbw/ears-movie.html?tracking=59983_B

DETECTORS IN SCIENCE THAT HELP US

Hearing Aid: A hearing aid is a small electronic device that you wear in or behind your ear. It makes some sounds louder so that a person with hearing loss can listen, communicate, and participate more fully in daily activities. A hearing aid can help people hear more in both quiet and noisy situations. However, only about one out of five people who would benefit from a hearing aid actually uses one.

A hearing aid has three basic parts: a microphone, amplifier, and speaker. The hearing aid receives sound through a microphone, which converts the sound waves to electrical signals and sends them to an amplifier. The amplifier increases the power of the signals and then sends them to the ear through a speaker.

ORGANISMS AND SOUND ENERGY:

Humans can hear frequencies between 20 and 20,000 Hz.

Elephants hearing range is between 1 and 20,000 Hz. The very low frequency sounds are in the “infrasound” range. Humans cannot hear sound in this range.

Dogs can hear sound as high as 40,000 Hz.

Mice can hear frequencies between 1,000 and 100,000 Hz.

SENSING SOUND ENERGYEcho Location: is the process of determining the distance and direction of objects by using sound.

Echolocation is performed by certain animals to locate food or obstacles in darkness, such as in caves and in the ocean. These animals, which include bats, toothed whales, oilbirds, cave swiftlets, and shrews, produce sounds and then listen for echoes. The delay between the emission of a sound and the arrival of an echo indicates the distance of an object.

Video: https://www.youtube.com/watch?v=j2VoouYxtQo

HOW ORGANISMS SENSE OTHER ENERGIES:

Earthworm’s entire body is covered with chemoreceptors (taste/chemical receptors)

Bats can detect warmth (thermal energy) of an animal from about 16cm away.

Cockroach can detect movement (kinetic energy) as small as 2,000 times the diameter of a hydrogen atom.

Star-nosed Mole use its fleshy star nose for hunting. It has 100,000 nerve fibers that run from star to the brain. This is almost six times more than the touch receptors in the human hand.

http://www.animalplanet.com/tv-shows/other/videos/fooled-by-nature-star-nosed-mole

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