Investigating Seed Germination

What about seed germination can you investigate?

The conditions needed for germination

Describe an experiment to investigate seed germination

1. Take four boiling tubes and put some cotton wool at the bottom of each one

2. Put 10 seeds on top of the cotton wool in each boiling tube

3. Set up each boiling tube as follows:

   • Tube 1: water, oxygen, room temperature (the control)

   • Tube 2: no water, oxygen, room temperature

   • Tube 3: water, oxygen, low temperature

   • Tube 4: water, no oxygen, room temperature

4. Leave the tubes for a few days and then observe what has happened

5. It’s important to control all of the variables during the experiment. You should only be changing on condition at a time so you know that any effect on germination is due to the change in that one condition.

6. So, in Tube 2, the only change from the control (Tube 1) is a lack of water. In Tube 3, only the temperature has changed. In Tube 4, the only change is the lack of oxygen.

Interpreting your observations - which tube will you see germination in?

Tube 1

Interpreting your observations - Explain why you only see germination in this tube

This is because all of the conditions needed for germination are present

Interpreting your observations - What will you see in the other boiling tubes?

The seeds won’t germinate

Interpreting your observations - What does this show?

This shows that seeds need water, oxygen and a suitable temperature to germinate.