It's a hot day and you want a cold drink: how long will it take for your chosen beverage to be chilled to its ideal temperature? Fortunately, there's a neat little online calculator that will give you the answer and save you the effort of constantly checking to see whether the drink is ready to … Continue reading Cool calculations
Specific Heat Capacity
Heating a substance can cause either an increase in temperature or a change of state. This is not completely obvious, so let me put it another way; sometimes when we "heat up" a substance it doesn't actually get any hotter. The reason for this is that the energy supplied is being used to break bonds … Continue reading Specific Heat Capacity
Surface Colour and Heating
Most people say you shouldn't go out on a summer's day wearing black because you will get too hot. It would be much better to wear white as this will keep you cooler. But is that actually true? We can test this idea using two boiling tubes that have been sprayed to have different surface … Continue reading Surface Colour and Heating
Thermal Equilibrium
Any object that has a constant temperature is in a state of thermal equilibrium. This means the rate at which energy is transferred to the object is exactly equal to the rate at which energy is transferred from the object. In the context of electromagnetic radiation, we can state that the rate at which the … Continue reading Thermal Equilibrium
Light and Heat
It is obvious to say that hot objects emit (give off) both visible light (a glow) and heat (that we can feel but not actually see). This is true of bonfires, light-bulbs and even our Sun. The connection between heat and light is taken completely for granted in everyday life: the glow of a hot … Continue reading Light and Heat
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