Alien Invasion was a special week organised by Sheffield Is My Planet and Sheffield Eco-Schools encouraging pupils to explore the question:
What would aliens think of the way in which we look after our planet?
We think if aliens visited us they would be worried about how Earth seems to be getting warmer and its climate and weather is changing.
They would probably say the evidence suggests that we humans are partly to blame, particularly from our burning of energy fuels such as oil, coal and gas.
And they would be amazed that thousands of people do not even do simple things that help, such as switching electrical appliances off standby, walking or cycling instead of using the car, recycling or switching off the tap when brushing their teeth.
Pupils came to school dressed as aliens for a day and signed up to receive:
Details of how to win cash prizes for eco-projects in our exciting competitions for the best eco-poster, eco-poem, alien costume and best eco-promise
The chance for the Sheffield Is My Planet mascot Gooshi to visit your school
We had lot of excellent entries for the Alien Invasion competitions, thank you to all those who entered. Click here to see more about the competion winners.