4 February 2008
Ross from Cannon Hill had a great question for us today on 4BC about Helium Gas.
Why does your vioce sound higher when you have inhaled helium gas?
When we talk, sound is produced by passing air over our vocal cords (flaps of tissue in our throats) causing them to vibrate thus producing soundwaves. The speed at which the sound waves are generated is what determines the pitch. Normally, we breathe air which is a mixture of gases containing mainly nitrogen and some oxygen and is heavier than helium. Sound waves through air moves at a fairly constant 350 metres per second.
Helium is less dense than the air we normally breathe and this means that sound waves travel through it much faster than usual (around 900 metres per second). This means that if you increase the speed of the sound waves, the frequency also has to go up and this means that our voices sound much higher than usual.
Therefore the faster the sound waves produced the higher the pitch. There are a lot of videos on You Tube of people inhaling helium which are quite funny. Remember though - whilst inhaling helium from a balloon won't necessarily kill you, it can make you dizzy and you could fall and hurt yourself. As well ... NEVER EVER ... inhale helium from the cannister as this can kill you due to the pressure behind the helium.
Helium is less dense than the air we normally breathe and this means that sound waves travel through it much faster than usual (around 900 metres per second). This means that if you increase the speed of the sound waves, the frequency also has to go up and this means that our voices sound much higher than usual.
Therefore the faster the sound waves produced the higher the pitch. There are a lot of videos on You Tube of people inhaling helium which are quite funny. Remember though - whilst inhaling helium from a balloon won't necessarily kill you, it can make you dizzy and you could fall and hurt yourself. As well ... NEVER EVER ... inhale helium from the cannister as this can kill you due to the pressure behind the helium.
1 February 2008
Morgan had a great question today about the weight of earth.
Does Earth get heavier with the increasing population and infrastructure associate with it?
It does get heavier. Every year, many tons of microdebris from space land on earth, approximately 40,000 tonnes, but it's really miniscule amount compared to the size of the earth and will never throw the earth off its axis.
Increasing population doesn't really change the weight of the earth – as people die new babies are born (which weigh significantly less than the people who die) as well when people die their bodies are cremated or decompose with equates to very little weight. Admittedly the population today is much more than that of hundreds of years ago, however the extra people balance out the shortfall below.
In regards to infrastructure the materials used to build are already here on earth just in different forms – so it’s really stuff that is already here just being moved around. This tends to reduce because events like fires destroy vegetation and buildings reducing it to nothing.
2 comments:
Hi Annie,
Just wondering what decides whether someone is left handed or right handed. Is it genes? Trev and I are both right handed but it looks like Madi is left as she draws much better and seems to prefer doing it with that hand.
Thanks!
Like many traits, handedness is probably determined by a complex interaction between genes and the environment. Whilst there are many theories out there ranging from a stressful birth to the size of the elbow, It now appears there may be some proof that genetics could be involved.
In 2007, researchers discovered LRRTM1, the first gene linked to increased odds of being left-handed. They think that this gene affects the symmetry of the brain. LRRTM1 is not essential for left-handedness, but it can be a strong contributing factor. They are still researching this gene.
It is interesting to note that people appear to inherit the gene from their fathers. It would be interesting to see if Trev has any lefthandedness in his family. A
Post a Comment