Teachers Note:
Title: “Seeds in space”
Disciplines: Science
Level: 
Description:
Grow lettuce seeds to find out how gravity and light influence their growth.
Ojbective(s):
Understand the necessity of performing experiments to study the infuence of some parameters in Science. Perform plant experiments. Observe and analyse the results.
Hints:
The conclusions can be as follows: Seeds on Earth grow in darkness against the direction of gravity. Seeds grow a bit faster in darkness, as if they’re racing towards the surface to receive light. Once above the soil, the direction of growth is also influenced by the direction of the light. Leaves need light to turn green.
Earth:
Light
On Earth, the box with light shows the seeds growing up. The leaves are green but the plants are short.
Darkness
On Earth, the box with darkness shows the seeds growing up. They’re tall, but the leaves are pale yellow.
You may want to introduce what an “experiment” is. There is a clever approach to learn about natural phenomena called ‘experiments’, a test in which you control or change certain circumstances that might influence the phenomenon. Let’s concentrate on the seeds issue. When you think about it, you may come up with a suggestion for the explanation of why seeds grow upwards.
We can easily test the suggestion that ‘light’ directs the growth of a plant. Just put some seeds in a dark box and some others in a box where light can enter. But it is not so easy to manipulate the influence of gravity, since we cannot just switch off the force.
However … an orbiting astronaut can! So what we do is to grow seeds in a dark and a light room, both on Earth and in space. During the Delta mission to the International Space Station (ISS) in April 2004, the ESA Dutch astronaut grew some seeds from the rocket plant (ruccola) in a dark box and some others in a box where light could enter. If we also grow our own seeds in the classroom in a dark box and in a light box, we will then be able to study the development of seeds the following combination of circumstances: light plus gravity, darkness plus gravity, light without gravity, darkness without gravity.