Remember, as a member of the Science Bus Club you can ‘Ask Albert’ a question about any of the topics. So if you’re not already a member join today!!
Words You Should Know
Temperature – a measure of how hot an object is
Thermometer – an instrument used to measure temperature
Degrees Celsius – the units used to measure temperature
Thermal Conductor – a material that lets heat pass through it
Thermal Insulator – a material that doesn’t let heat pass through it
Insulate – to keep heat in
Conduct – when heat travels through a material
Here’s a fun experiment:
Working in pairs, one of you put your hand in a bowl of cold water (put some ice cubes in it to make it even colder) and one of you put your hand into a bowl of hot (not too hot of course) water. After a few seconds take your hands out of the water and into a third bowl of water. Is the water hot or cold?
Based on this experiment do you think touch is the best way to determine if things are hot or cold?
Thermometers
A thermometer is a device that measures temperature or temperature gradient, using a variety of different principles. The word thermometer is derived from two smaller word fragments: thermo from the Greek for heat and meter from Greek, meaning to measure.
A thermometer has two important elements, the temperature sensor (e.g. the bulb on a mercury thermometer) in which some physical change occurs with temperature, plus some means of converting this physical change into a value (e.g. the scale on a mercury thermometer). Industrial thermometers commonly use electronic means to provide a digital display or input to a computer.
Thermometers can be divided into two groups according to the level of knowledge about the physical basis of the underlying thermodynamic laws and quantities. For primary thermometers the measured property of matter is known so well that temperature can be calculated without any unknown quantities. Examples of these are thermometers based on the equation of state of a gas, on the velocity of sound in a gas, on the thermal noise (see Johnson–Nyquist noise) voltage or current of an electrical resistor, and on the angular anisotropy of gamma ray emission of certain radioactive nuclei in a magnetic field.
Secondary thermometers are most widely used because of their convenience. Also, they are often much more sensitive than primary ones. For secondary thermometers knowledge of the measured property is not sufficient to allow direct calculation of temperature. They have to be calibrated against a primary thermometer at least at one temperature or at a number of fixed temperatures. Such fixed points, for example, triple points and superconducting transitions, occur reproducibly at the same temperature.
Internationally agreed temperature scales are based on fixed points and interpolating thermometers. The most recent official temperature scale is the International Temperature Scale of 1990. It extends from 0.65 K to approximately 1358 K (−272.5 °C to 1085 °C).
We use a thermometer to measure temperature.
Here’s a fun experiment to do using a thermometer:
Carefully take thermometer readings for each of the following situations:
Held in the air- Blown across
Held under a cold tap
Placed in a beaker of water and left for one hour
Placed in a beaker of freshly made tea
- Placed in a cup of tea that has been left standing for 15 minutes
Remember take extra care with this, it’s probably best to do this with and adult present!!!
Here are some questions, can you find the answers?
If an ice cube is left at room temperature what happens to it and why does this happen?
If a cup of tea is left at room temperature what happens to it and why does this happen?
If you measure the temperature of a room in different locations are the y different? If they are do you know why? Does the temperature change at different times of the day? If so do you know why?
Keeping Warm In Winter
In winter humans wear different clothes to keep them warm outside. They wear things such as, scarves, gloves, hats and thick coats. All of these things will ‘insulate’ the person wearing them. Insulate is an important word to remember!! There’s more information about insulators below!!
Insulators
Insulator is a material that resists the flow of electric current. It is an object intended to support or separate electrical conductors without passing current through itself. An insulation material has atoms with tightly bonded valence electrons. The term electrical insulation has the same meaning as the term dielectric.
Some materials such as
silicon dioxide or
teflon are very good electrical insulators. A much larger class of materials, for example rubber-like polymers and most plastics are still "good enough" to insulate
electrical wiring and
cables even though they may have lower bulk
resistivity. These materials can serve as practical and safe insulators for low to moderate voltages (hundreds, or even thousands, of
volts).
Remember, as a member of the Science Bus Club you can ‘Ask Albert’ a question about any of the topics. So if you’re not already a member join today!!
