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Scientific activity Living world 3 Germination

Seed That Grows

What does a seed need to germinate? In this activity, you will compare several environmental conditions to observe what promotes, slows down, or prevents germination.

Duration
10 to 15 minutes to set up + 7 to 10 days of observation
Difficulty
Very easy
Theme
Germination 3 Environmental conditions

What to Understand Before Starting

What Does a Seed Need?

  • Water to rehydrate and restart its activity.
  • Oxygen to breathe and produce energy.
  • An appropriate temperature to allow the reactions necessary for germination.
  • Light is not always essential for germination but becomes important later for the normal growth of the young plant.
To understand the effect of one factor well, test it alone while keeping everything else the same.

What You Can Observe

  • The number of seeds germinated.
  • The time taken before the radicle appears.
  • The length of the radicle.
  • The general appearance: color, mold, thin stem, pale seedlings, etc.
A seed is considered germinated when the radicle, the first small root, appears.
Important Rule: in a scientific comparison, only one factor is changed at a time.

Scientific Problem

General Question

Which environmental conditions influence the germination and the start of growth of a seed?

Initial Idea

A seed normally germinates when it has water, oxygen, and a suitable temperature. Depending on the conditions, germination can be slowed down, prevented, or occur differently.

This activity allows you to compare a reference setup with other situations to understand the roles of water, light, temperature, and the seed type.

Materials

Main Materials

  • Seeds: lentils, beans, or other easily germinated seeds
  • Several small transparent containers or bags
  • Cotton or paper towels
  • Water
  • Labels and a marker
  • A ruler to measure the radicle
  • A sheet of paper or notebook to record observations

Optional Materials Depending on Versions

  • An opaque box or a dark cupboard
  • A cooler room
  • A slightly warmer spot
  • A thermometer if available
It is not necessary to have lots of material: the key point is to make good comparisons.
Hygiene: Wash your hands after handling. If a culture molds heavily, do not touch it unnecessarily and throw it away.

Choose a Comparison

You can start with the reference setup and then add another version to compare. It is not necessary to do everything at once.

Click on a version to display its protocol.

Tip: Start with the reference setup, then choose just one other version for a true comparison.

Reference Setup

Goal

This setup serves as a comparison base. It places seeds in favorable conditions: correct moisture, access to air, ambient temperature.

What Must Remain Constant

  • The same number of seeds
  • The same support
  • The same amount of water
  • The same observation duration

Setting Up

Prepare a container A and place a layer of cotton or paper towel at the bottom.
Moisten the support: it must be damp but without any puddles of water.
Place 10 seeds spaced apart from each other.
Place the container at room temperature, in a normally lit area.
Observe daily and lightly moisten again if necessary.
To Avoid
  • Too much water, which limits available oxygen.
  • Seeds too crowded together.
  • Direct sunlight exposure, which quickly dries the support.

Tracking Setup A

Day Seeds Germinated (out of 10) % Germination Average Radicle Length Observations
D1
D2
D3
D4
D5
D6
D7

Compare Light and Darkness

What We Compare

Two identical setups, except for light exposure.

  • A: normal light
  • B: darkness

What to Expect

Many seeds can germinate in the dark thanks to their reserves, but young seedlings often become paler and more slender.

Setting Up

Prepare B exactly like A.
Place B in an opaque box or in a dark place.
Quickly observe each day, then return it to darkness.
Expected Observation: germination may be close to that of the reference setup, but the appearance of the seedlings often changes.
Setup Light Seeds Germinated % Germination Average Length Appearance
ANormal light
BDarkness

Compare Different Amounts of Water

What We Compare

  • A: moist support, without excess
  • C: very little water
  • D: too much water

What to Expect

A seed needs water to germinate, but also oxygen. Too little water blocks germination, too much water can slow it down and promote mold.

Setting Up

Prepare C with a barely moist support.
Prepare D with a very wet support, with visible excess water.
Observe daily the germination speed, odor, and possible appearance of mold.
Warning: if the overly wet setup molds heavily, stop the test and discard it.
Setup Moisture Seeds Germinated % Germination Speed Observations
AMoist
CVery little water
DToo much water

Compare Cool and Warm Temperatures

What We Compare

  • A: Room temperature
  • E: Cooler place
  • F: Warmer place

What to Expect

Temperature influences the speed of biological reactions. A favorable temperature usually speeds up germination, while a too low temperature slows it down.

Setting Up

Prepare E and F exactly like setup A.
Place E in a cooler area.
Place F in a slightly warm spot, never too hot.
Observe mainly the speed of radicle appearance.
Expected Observation: under favorable conditions, the warm setup often germinates faster than the cool one.
Setup Temperature Seeds Germinated % Germination Average Day of Appearance Observations
A
E
F

Compare Two Types of Seeds

What We Compare

  • A: one seed type
  • G: another seed type

What to Expect

Different species do not always germinate at the same speed nor achieve the same germination percentage.

Setting Up

Prepare G like A, but with another seed type.
Keep exactly the same light, water, and temperature conditions.
Compare germination speed, percentage, and radicle sizes.
Setup Seed Type Seeds Germinated % Germination Average Day of Appearance Observations
A
G
Expected Observation: each species has its own germination rhythm.

Compare and Conclude

How to Build a Conclusion

  • Mention the setups compared
  • Quote one or two precise results
  • Say what this shows
  • Briefly explain why
A good conclusion always relies on concrete observations.

Key Takeaways

  • Water is essential, but excess hinders respiration.
  • Temperature influences germination speed.
  • Light is not always necessary for germination but is important later for normal growth.
  • Not all seeds behave the same way.

Analysis Questions

1. In which situation was germination the fastest?

2. Which condition slowed germination the most?

3. Is light essential for germination?

4. What did you control well to make the comparison reliable?

Hints to Help You
  • Water is essential for germination.
  • Excess water can block oxygen access.
  • Temperature often affects germination speed.
  • Light mainly becomes important after germination for normal seedling growth.
SVsansT 3 Activity "Seed That Grows" 3 Understanding how environmental conditions influence germination.
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