BRAINDUMP
Amazing answers to your curious questions
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Did you know?
Aomori City in Japan has the highest average snowfall
Why is snow white?
Katy Kruick
To answer this question there are two things which need to be considered – colour theory and refraction. Refraction is the change in direction of light as it goes from one material to another. It’s due to a slight change in the speed of the light, and it explains why straws look bent in water. When light enters snow, it refracts. This is because snow is
made from lots of ice crystals tightly packed together, the important fact here being that these crystals are translucent – light can pass through, but not in a direct path; it changes direction.
Additive colour mixing tells us that if we combine all of the frequencies of colours we get white light. When light falls on snow it is composed of a mixture of different frequencies which all refract slightly differently as they enter the ice crystals. Eventually, due to refraction, the light leaves the surface of the snow in all directions and hits our eyes. This light is composed of a mixture of frequencies, which our eyes detect as white light.
WHAT IS AN INDIAN SUMMER?
Nigel Peterson
The definition of an Indian summer is a period of mild sunny weather that is out of season. The term is commonly used to describe a sunny spell which can occur after the first frost. The first recorded usage of the term was in 1778, by a Frenchman who lived in America called John de Crèvecœur who mentioned it in a letter. The term had spread to Britain by the 19th century.
Indian summers are caused by stalled high pressure; this high pressure pushes air towards areas of low pressure, which makes wind. Due to the rotation of the Earth, these winds rotate counterclockwise about the Northern Hemisphere and can sometimes curve south, picking up warmer air and bringing it further north, and making it unseasonably warm.
HOW DOES A GALILEO THERMOMETER WORK?
Sarah Cook
The Galileo thermometer consists of a vertical glass tube, typically filled with water, and sealed glass bubbles containing coloured water or alcohol. Each bubble is also attached to a specific mass and labelled with the temperature it represents to calibrate its density. The temperature can be read by interpreting the distribution of these bubbles. The principle of buoyancy states that if an object is less dense than a liquid, it floats, and if the object is denser than the liquid, it sinks. When the temperature of the liquid in the glass tube begins to warm up, it expands – hence lowering the density of the liquid, as its mass now occupies a larger volume. The opposite occurs when the temperature cools. Therefore, if a bubble becomes denser compared to the liquid, it will sink; and if it’s less dense it will float.