What do seeds need to germinate?
Set up dishes of bean seeds with and without water, warmth, air and light, and count how many germinate each day.
Core concept
In short: Find out what a seed needs to start growing: water, warmth or light?
Seeds need water, warmth and oxygen (air) to germinate; light is not needed until the seedling grows
Topic: Plants
germination: When a seed starts to grow into a new plant. All key words is when a seed starts to grow into a new plant: first a root pushes out, then a shoot. A seed carries a store of food, so it does not need light at first. It does need water to soften the seed coat and start its chemical reactions, a suitable warm temperature, and oxygen: A gas in the air that living things need to breathe and that fire needs to burn. All key words from the air for respiration. To test each condition fairly, set up several dishes that are identical except for the one condition you change, and compare them with a control dish.
What you will learn
- Identify the conditions seeds need to germinate.
- Plan a fair test with a control and one changed variable.
- Explain why light is not needed for germination.
Before you start
- Know that plants grow from seeds.
Materials
- Bean or chickpea seeds, cotton wool, water, boiled cooled water and a little cooking oil
Equipment
- Petri dishes or small bowls, a refrigerator and a dark cupboard
Procedure
- Control: moist cotton wool, room temperature, air and light. Record the seeds germinated on days 2 and 7.
- Change one condition at a time: dry, in the fridge, under boiled water with oil on top (no air), in the dark.
- Record each dish on day 7 and compare it with the control.
How this simulation is simplified
- The bean seeds are healthy; germination follows a simple S-shaped curve whose speed depends on the conditions.