The liquid iron outer core of the Earth is in constant motion due to convecting heat and the rotation of the planet. This causes the magnetic field to move and shift around. Roughly every million years the magnetic field flips entirely about 4 or 5 times, so that the north and south poles swap places. The last one took place about 780,000 years ago during the Stone Age.

We see evidence for this in the new crust that is created between tectonic plates as they move apart. The mid-ocean ridge in the floor of the Atlantic Ocean shows many field reversals, with magnetic patterns in the hardened lava showing the history of the Earth’s magnetic field.

There seems to be a reduction in the magnetic field at present, suggesting that a reversal may take place in the next couple of thousand years. A reversal happens gradually and so would go largely unnoticed. There is no scientific consensus as to the effects that would be experienced. With the weaker magnetic field providing less protection to Earth, it is possible that the effects of the solar wind may be stronger. This might cause holes in the Earth’s ozone layer and increase the rates of skin cancer. However, the atmosphere would still provide considerable protection and so it is also possible that these effects may be minimal.

Some animals, such as pigeons, bees and whales, are thought to use the Earth’s magnetic field for navigation. It is therefore theoretically possible that they may become disorientated at this time. However, the slowness of the reversal may also mean that individuals are able to adapt.
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- Catherine Bell

Hey Daisy. What a unique and interesting question. Thanks for writing in. My guess, in a nutshell - in response to the answer to your question is… Not much.

If you remember the sentence to help you remember the order of the planets from the sun, you'll remember Mars is one planet further down the line from us. So... Mars gets about 40% less sunlight than Earth does. So how much heat does Mars absorb? Very little. A cold, red, lifeless rock of rust. But an amazing planet, named after the ancient God of War. 

Scientists think Mars may have been a more living, active planet, a billion or so years ago. With rivers, lakes and seas. And this time of year is an excellent time to see Mars, with your own eyes, floating in the southern sky. A large red "star" that doesn't twinkle, clear sign of planetary behaviour.
I hope you enjoyed our visit to St Paul's, a fantastic school and always a treat for us. Blast Science are doing a series of free science shows on the Pier this summer. Check it out with your family.
And I hope you continue to be an inquisitive scientist. And have a fantastic summer.

- Brad, Blast Science.

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Hello Daisy. Quick answer : very little.
Long answer: Mars is much colder than Earth, not only because it’s farther from the Sun but because its thinner atmosphere does not support a strong greenhouse effect. When visible light from the sun strikes the surface of Mars, it’s absorbed and converted to heat. The planet re-radiates some of this heat into space in the form of infrared radiation. Greenhouse gases such as CO2 are transparent to visible light but absorb strongly in the infrared part of the light spectrum. The gases act as a blanket that traps the heat and raises the temperature. This effect is similar to greenhouse glass, which keeps the air warm inside.
The Martian atmosphere is more than 95 percent CO2 by volume. The remaining gases are a mixture of nitrogen, argon, oxygen and carbon monoxide. CO2 is a potent greenhouse gas, so Mars does have a greenhouse effect. But it is very weak because the Martian atmosphere is so thin -- 100 times less dense than the Earth’s atmosphere.

Some scientists have speculated that Mars once had a stronger greenhouse effect. In 1971, for example, data from the Mariner 9 spacecraft showed that the surface temperature on Mars increased significantly during a dust storm, which temporarily trapped more heat near the planet’s surface. Astronomer Carl Sagan pointed out that under the right conditions, a sufficient increase in surface temperature would melt the Martian polar ice caps. This was possible because Martian clouds are made of frozen CO2. When heated sufficiently, the CO2 would thicken the atmosphere and contribute to further warming. Sagan and other astronomers speculated that events of this kind might have occurred earlier in the Red Planet’s history.

Currently, the greenhouse effect on Mars is very weak. However, some scientists wonder whether it is possible to make Mars more habitable by thickening its atmosphere. This approach, they say, might create a stronger greenhouse effect and make Mars a warmer planet. Because it’s not clear how much CO2 the Martian polar caps contain, scientists aren’t sure how much additional CO2 would be needed to warm the Martian surface. Other possibilities include adding different greenhouse gases such as perfluorocarbons (PFCs) to the atmosphere.
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- Alex Nicholls.

Hi Abel – great question. We showed you the non-Newtonian substance made of custard and powder and water in the Wizard Science Show we did in your brilliant school – so great you want to know more!

A solid as we discussed is made up of molecules that are tightly packed together. A liquid is made up of meolecules that are further apart and can move around more easily and take the shape of what they are in.
The molecules in cornflour (or custard powder that is made of cornflour) can move very close together when they are squashed and act like a solid. When you let go, the molecules move apart and start acting like a liquid which is why the substance can then fall through your fingers. So it is really both a solid and a liquid at the same time! If you fill a whole swimming pool (or even a paddling pool) with cornflour and water you can then walk across the top of it – the pressure of your feet pushing down keeps it solid under your feet. However if you stop walking, the molecules move apart and you sink (like quick sand!). There is a fantastic youtube video showing this, where Richard Hammond from Brainiac walks on custard. Check it out below!

Thanks for your brilliant question, stay curious and see you soon!!
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- Lydia from Blast Science