Thermometers a mechanical or electrical device for measuring

Thermometers -a mechanical or electrical device for measuring temperature REMEMBER: 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

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

Used for: Identifying where houses are losing heat Finding where motorized parts are overheating Where electrical devices have a short

Identifying weather patterns

Exploring outer space.

No suspects Suspected image-2 nd Can you spot the person in this picture who has the flu?