Thermometers-a mechanical or electrical device

for measuring temperatureREMEMBER: temperature is the AVERAGE speed of the

particles!

Temperature Scales

Farhrenheit

The Right Device for the Job

-a regular laboratory thermometer is not always the best device to use

Ex. Lab Thermometers have a scale that goes from -20 degrees Celsius to 110 degrees Celsius

•In what situations would this pose a problem?

-thermometers have been developed to suit almost every purpose

-most thermometers have these three parts:

i) SENSOR – a material which is affected by the change in temperature ex. water gets heated

ii) -the sensor produces a SIGNAL – information about the temperature ex. water rising up/down the tube

iii) -the signal affects a RESPONDER – light, pointer, or other mechanism that use the signal ex. water is read on the scale

Four Types of Thermometers

•not all thermometers are created equal

•Some have different properties that allow them to work better than others under certain conditions

•two different metals (usually copper and iron) that are twisted together

1. THERMOCOUPLE

•when the metals are heated, a small amount of current electricity is produced

•the larger the current of electricity, the hotter the temperature!

USES: -measuring very high temperatures

-stoves, furnaces

2. BIMETALLIC STRIPS

-relies on the fact that different metals expand at different rates as they warm up.

-by bonding two different metals together, you can make a simple electric controller that can withstand fairly high temperatures. This sort of controller is often found in ovens.

By bonding two different metals together, you can make a simple electric controller that can withstand fairly high temperatures. This sort of controller is often found in ovens.

                                                                                              

                                           

3. RECORDING THERMOMETER-records the temperature of an area over a long period of time

-a pen, connected to a bimetallic strip, records the temp on a rotating drum

-as the bimetallic strip flexes, it moves the needle up or down based on the paper

-can be used to measure temp over days, weeks, even years!!

4. INFRARED THERMOGRAMS

-a device (camera) that measures the amount of radiant energy given off by an object

-can tell the temperature of an object from a great distance away

-hotter objects - yellows, reds and whites

-colder objects – blues, purple, and black

Finding where motorized parts are overheating

Where electrical devices have a short

Used for:

Identifying where houses are losing heat

Identifying weather patterns

Exploring outer space.

No suspects Suspected image-2nd No suspects Suspected image-2nd

Can you spot the person in this picture who has the flu?