How much caffeine in coffee?

We worked with caffeine in combined science a few weeks ago But how much caffeine is there in coffee and how does it work?

What if all the ice melted?

How would the world look if all the icecaps in the world melted and the sea level rised?

National geographic have made some nice interactive maps

Heart rate and exercise

Last week we looked on how exercise affects the heart rate. The video can be found here

The effect of adrenaline

We looked on adrenalines effect on peak power and heart rate today. Here are the movies we used

Adrenaline is one of the many hormons that makes up the amazing control system that works trough our bodies-

All hormones are chemical substances produced in a gland in the body, that are carried by the blood and alters the activity of one or more specific target organs and then is destroyed in the liver.

Adrenaline is the action hormone. It comes from the adrenal glands above the liver. When we are subjected to a sudden stress, the brain signals the gland to release adrenaline into the bloodstream.

Adrenaline increases the heart rate, and increases the oxygen supply to the body and brain. It also causes the liver to release glucose into the bloodstream, and the body to break down fat at a faster rateSo, it primes the body for sudden action, and supply extra supplies for respiration.

It prepares you to either fight or run away.

Too much adrenaline is not beneficial, as motor control and skills tend to degrade one the pulse gets above 150-150 BPM, but some adrenaline will make you stronger and faster

Long time stress, on the other hand, can break down the body and make it weaker, but for short time stress actions, we have a super effective system.

reaction speed

Today in combined science, we will be meassuring reaction speed using this small program

reaction time

New blog, new direction

After 6 exciting years as a science and math teacher at the wonderful¨school Himmerlands Ungdomsskole., I have now changed to Ranum efterskole, where I will be teaching Combined science and math. I will also be having science classes in danish.These will still be at my usual blog

In this blog I will try to write about all the fun and exciting science we will be having fun with at Ranum Efterskole. Ranum have this year gone all in with the Cambridge system, and it's a perfect way to combine english as a second language and the joys of the danish boarding school system.

All material here will be things I write myself or movies I make at shcool. I will also include public youtube clips to help my students to grasp the most important aspects of combined science.

If you want to use anything for your own studies or teaching, be my guest ;)

All gramatical and spelling errors are due to the fact that I am mainy a sciencegeek and I have english as a second language. Please feel free to contact me if I get the science wrong, but don't correct my spelling.. I know it's lacking 

Hope you still will enjoy it  and find a bit of inspiration.

Stay tuned!

Mammalian hearts

In combined science we have started working with the heart and circulatory system of mammals.

The heart is a complex system, with an enormous capacity for work. Think about it. Every day, every hour, every minute, pretty much every second the heart contracts and sends oxygenated blood to your working muscle and carries CO2 and waste products away. 




Blood gets oxygenated in the lungs. The lungs have such a huge area that oxygen diffuses into the blood, while CO2 diffuses out. 

Image borrowed from The british heart foundation



The oxygenated blood now enters the heart trough the pulmonary vein and into the left atrium.


From the left atrium it enters the left ventricle. When the heart contracts, the valves close down to stop the blood flow from reversing.

With great force the blood is then pumped out into the Aorta, where it separates into 2 different main arteries. One for the body and one for the head.

The arteries then branches out until he blood reaches the working tissue. Here the large vessels have now been replaced by tiny capillaries that make diffusion of oxygen from the blood to the working tissue a lot easier.

The blood have now released most of its oxygen and have taken up quit a lot of CO2. It now flows trough the veins back to the heart. It enters the right atrium and then the right ventricle, where it is pumped to the lungs. Here the blood releases the CO2 and binds new O2 and the cycle is complete