How far do sounds travel?

In today’s science lesson, we carried out an experiment to test the distance over which different sounds were audible (which we found ranged from 5-6 metres for the sound of hands being rubbed together to 50-60 metres for the noise made by a shaker full of pins) and we discussed why sounds become quieter as the listener moves away from the source of the sound.  As usual, you can ask your children to explain!

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Science week – science in Ancient Greece

In today’s history lesson, we learned how the Ancient Greek civilisation made important contributions to many areas of science.

In medicine, for example, Hippocrates established the world’s first medical school as well as the famous medical standard – the Hippocratic Oath – still used by doctors.  The ancient Greeks even argued for the importance of healthy eating, something that modern-day societies have only recently, it seems, started to understand and take more seriously.  

We also learned that the Ancient Greeks were great astronomers, mapping our modern system of star constellations and giving the constellations names.  They proposed the heliocentric model of the planets revolving around the sun. (We found out that the word heliocentric comes from the Greek – “helios” meaning sun, and “kentron” meaning centre).  It is amazing to consider that Galileo was imprisoned in Italy nearly 2000 years later for supporting the same idea.

In the language part of the lesson, we looked at the Greek alphabet and the children had fun writing their names using the Ancient Greek characters. 

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Science week – string telephones

We explored the idea of a “string telephone” and how they work in a similar way to the old landline telephone system.   We tried out a few different designs of string phone and got one to work over the length of the KS2 hall (about 50 feet).   We also tried designs using ribbon and cotton thread (which worked, but not as well) and metal wire (which didn’t seem to work for some reason – perhaps because it was difficult to get the wire straight and taut).  This would be a fun activity to try at home.  If you build a good telephone, why not bring it in to show the class.

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Science week – measuring the volume of different sounds

We used the free app. dbMeter to measure the volume of lots of different sounds.  We found that the background noise in a “silent” classroom was about 30 decibels and measured the volume of sound that we could generate with shakers filled with different materials.   The results ranged from 32 decibels for a shaker filled with feathers to 100 decibels for a shaker filled with coins.

We also tried to see how a candle flame would respond to a sound wave by holding it in front of a speaker playing loud music.   We expected the flame to flicker but nothing happened!   Perhaps you could try this at home.   And here’s a question to research:  what do some scientists say is the loudest sound ever recorded?

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Ecobricks – request for waste plastic

As part of our Reduce, Reuse, Recycle science week, we’ll be making Ecobricks – plastic bottles packed with clean and dry waste plastic – that can be used as building blocks for furniture, walls or larger structures.   

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The more densely we pack the bricks with plastic the better the quality of the brick and the more plastic we will have removed from the environment.  It would be great if as many children as possible could bring some waste plastic into school on Monday.

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How sound travels

In science, we recapped how vibrating objects create a sound wave in the air which travels to your ear and enables you to hear the sound.  We convinced ourselves with some simple tests that sound waves could pass through solids (the thickness of the classroom tables, for example) as well as through air.  We also learned that sound waves, in fact, pass more quickly through solids than liquids, and more quickly through liquids than air, and discussed why this is.  Do ask your children to explain.8-l-sound-hearing-boardworks-16-638

Good vibrations

We’ve started a new science topic – sound.   We’ll look at how sounds are generated and travel to our ears and at how we can make sounds louder and quieter, higher and lower.  

To get started, we thought about the many different qualities of sound and observed how a vibrating tuning fork generated a sound that we could hear when we held it close to our ear – and that the sound became louder when the tuning fork was placed on an object (one of the classroom tables, for example) which also started vibrating and generating a sound.

img_3453 But here’s what seemed to be the key question for the class: How fast does sound travel and can a car travel faster than the speed of sound?  I’ve encouraged the children to do a little research to find the answer before next week’s science lesson.

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Melting ice

Working with Mr Cranston today, the children looked at factors affecting the rate at which ice melts – the size of the ice block, its shape and the temperature of the surroundings.  

An interesting side note was that the level of the water in the containers did not increase after the ice had melted.   We discussed how this was because the ice was already floating in the water and displacing the same volume of water that it would contribute when it melted.  (You could try this out at home if you want convincing.) So, melting ice bergs will not raise the sea level, although the melting of land ice will.