Odd One Out

What goes up must come down

Activity overview

15 mins
Ages 7 – 9

Science topics:


Put your class’ observation skills to the test with these three images showing take-off, landing and re-entry on a robotic mission to Mars. This activity is great for promoting observation and discussion skills as well as applying children’s understanding of forces.

Run the activity

1. Show the three images above and ask everyone to come up with as many similarities and differences as they can.  

If they get stuck, prompt them to think about:

  • appearance
  • what they do
  • where they might be found

2. Then, everyone needs to decide which one is the odd one out and why. Encourage a reason for every answer and there is no wrong answer!

Background science

The images of the Proton Rocket, Schiaparelli lander, and parachute all show different stages in the European Space Agency’s (ESA) ExoMars mission. The rover is launched from planet Earth using a Proton Rocket and takes nine months to travel to Mars where it searches for signs of life.

The first image shows the Proton Rocket, shortly after take-off. The force, due to the Earth’s gravity, pulls the rocket down. The thrust force from the engines pushes the rocket upwards. As the rocket travels upwards, it experiences air resistance (a type of friction force), pushing it downwards. We observe that the rocket is accelerating upwards, so know that the thrust force is bigger than the force due to gravity and air resistance combined  

The second image shows the Schiaparelli lander descending onto the surface of Mars (an artist’s impression). Schiaparelli is being pulled down with the force of Mars’ gravity, which is less than half of the force of gravity on Earth. The Schiaparelli lander will also be experiencing air resistance pushing it upwards. The lander has three downwards thrusters that push the lander upwards to slow it down so that it doesn’t hit the surface of Mars with too much impact. 

The third image shows the mission to test the parachute for the ExoMars rover’s descent onto the surface of Mars. This is the largest parachute ever to fly on a Mars mission. When heading down to the surface of Mars, the ExoMars rover will enter the Martian atmosphere at a speed of 21,00km/h (more than five times the speed of a bullet). The parachute will be deployed to create a huge upwards air resistance force, pulling the rover upwards and slowing the rover down, while the force of gravity pulls it downwards. The parachute is slowing the rover down while it travels downwards.


The 2022 ExoMars mission is looking for signs of life on Mars. We've got lots of activities to support your own Mars exploration. Read more on our blog! 

Take it further

Parachutes are often used on European Space Agency missions to slow down vehicles and landers as they descend. Why not develop the children's understanding of contact and non-contact forces by investigating parachutes in the classroom? Check out the Soft Landings activity in ESERO’s Rosetta Primary Resource Book or take a look at the low altitude practice parachute drop or Schiaparelli’s descent to Mars in action. 

Have a go at Build an egg parachute or STEM Learning's The Mars Mission: Landing and Exploring to put the learning into action or have a think what life would be like if There was no gravity?

Image Credits: NASA/ESA via NASAESA/ATG medialab via ESAESA & Vorticity Ltd via ESA