Overview – Understanding Homeostasis

This is how the body regulates it’s Temperature, Pressure, the flow and distribution of blood (circulatory) and other liquids in the body, the amount of calcium in your bones and many other things. It works by feedback loops, the same as Cornelis Drebbel’s automated oven. We have used loops in Scratch and it is a similar process that maintains the body.

The Human body has developed to survive on Earth, with the weight of the Earth’s atmosphere (1 atms or 101000 Pa or Pascals) holding us together. It also likes to keep a temperature of around 37°C.

Humans can adapt to survive in a great range of pressures, however if too low you will have very little air to breath and the gasses in your body will want to expand larger then the cells in your body. At high pressure you will eventually get to a point where the body is crushed again making it hard for lungs to expand. However change in pressure requires a force, imagine what happens when you pop a balloon, the gas doesn’t often escape slowly, it escapes all at once damaging the balloon and causing it to pop. That is why there are airlocks on spacecraft and submarines, to allow the body time to get used to the change in pressure. However there is a limit to lower pressure based on the fact that Water boils at a lower temperature as pressure drops, at around 6000 Pa water boils at 37°C so the water in out bodies starts to boil (this is known as the Armstrong limit), any lower pressure then 6000Pa and this becomes more extreme.


These can be seen in this clip from Richard Hammond’s Engineering Connections Episode: Super Tankers. Water Boiling at Room Temperatures, Under a Vacuum

The opposite is true of temperature, where humans can adapt to short term changes, by sweating or by retracting blood vessels from the skins surface, but at temperatures below 35°C the body will start to experience hypothermia (Shivering) and above 38°C Hyperthermia (heat stroke) both can be dangerous if prolonged or the larger the temperature difference is to 37°C.

Play the Game

Activity – A Marshmallow is trapped in a closed Syringe and a Balloon. Show the effects of Pressure and Temperature on gasses
Start the Game – Click anywhere on the left to start. Press the Green Flag to Restart & try another command
How to Control – Type in a phrase below:
push – Push plunger closed
pull – Pull plunger closed
hot – Move to hot place
cold – Move to cold place
high – Move to high pressure
low – Move to low pressure

Play the Game

Activity – Space Cat is Protected from changes of Temperature and Pressure with her space suit. Cat did not wear a space suit and is not protected.
Start the Game – Click anywhere on the left to start. Press the Green Flag to Restart
How to Control – 
a – Cold environment
b – Hot environment
c – Place with High Pressure
d – Place with Low Pressure
e – Return Home

Play the Game

Objective – Control the Cat, you must quickly get your Space Suit on then your Helmet before the pressure becomes too much
Start the Game – Click anywhere on the left to start. Press the Green Flag to Restart
How to Control – Use the Cursor Keys to Move

The Pressure on Mars is about  0.6% of Earth’s Pressure (600 Pa) and the Temperature on Mars ranges from 20°C to -120°C so Humans living on Mars would need protective suits and buildings able to protect people from the harsh Martian conditions.

Now that out Astronaut is prepared for a change in temperature and pressure, next they will need to breath.

The atmosphere of Mars is mostly Carbon Dioxide with only the smallest trace of Oxygen, where the Earth is mostly Nitrogen with about 20% Oxygen (or 1 in every 5 particles is Oxygen). Experiments on Earth have shown that humans can survive with as little as 17% Oxygen in the air we breath until hypoxia begins to occur. This is similar to the effects of altitude on the Human body, where you would become short of breath and have headaches and eventually will lead to death. So fresh Oxygen will need to be made for people to breath.

The easiest way would be to take the Oxygen from the Carbon Dioxide, as shown by this simple Electrolysis chemical equation

2CO2 + Electricity → 2CO + O2


Try this at home or at school with water. Investigating an experiment involving the electrolysis of water

The Curiosity Rover

Curiosity is a car-sized robotic rover exploring Gale Crater on Mars as part of NASA’s Mars Science Laboratory mission.

Fact Sheet

Activity – Find out about The Curiosity Rover
Start the Game – Click anywhere on the left to start. Press the Green Flag to Restart
How to Control – Press the Space Bar to find out about the Curiosity Rover. Keep tapping the Space Bar to scroll through all the facts

Further Materials, Resources & Information

Below you will find more resources and external websites related to this lesson.

Full STEAM Ahead – Space Exploration Education Grant

UK Space AgencyThis lesson has been produced as part of the Full STEAM Ahead Project with the UK Space Agency. We are one of eight organisations across the UK to be awarded to deliver and produce exciting new education outreach activities and projects. The UK Space Agency are delighted to be able to support these projects, which represent a diverse selection of cross-curricular activities that meet it’s education objectives in encouraging children to take up STEAM subjects, raise awareness of careers in space-related areas, and raise awareness of the UK’s exploration programme.


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Sandie on the New Skills, New Life Course “I have only been at G2G Communities for a short time but have gained valuable experience in computer skills. All the staff has been friendly and helpful. It has not only improved my computer skills, but has also helped me with my own self confidence. If anyone was to ask if doing this course was worth it I would certainly encourage them to do it.” – Read the full article >


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Charles on The New Skills, New Life Course “I have learned a lot here, all the one to one support has helped me learn quicker and better, any problems I have had they sit down with me and talk it over, which personally I find easier to handle rather than someone standing in front of a class and just dictating to me. This course has helped me to get job interviews, has given me confidence to ask questions and get answers, I am very glad to have been on this course.” – Read the full article >

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