How the Amount of Water Effects Plant Growth:

Hypothesis: Water increases a plant’s growth until a certain point.
Aim: To investigate if the effects of water on plant are always positive.

Equipment:
• 1 Packet of radish seeds
• 3 small plastic plant pots
• Soil
• A watering can
• Water
• Light source (sunlight)

Method:
1. Set up your 3 pots at a place outside which a) is out of the way of constant movement e.g. not in the middle of a verandah, so that they will not have to be moved and are safe from animals, b) receives an adequate amount of sunlight (allowing all 3 pots equal sunlight) and c) sheltered from strong winds
2. Fill the pots with soil up to 2 inch below the rim. Make sure that all pots are using the same soil and are filled equally.
3. Sprinkle the radish seeds thinly and evenly on top of the soil across the 3 pots.
4. Cover these seeds with an inch of soil across each of the pots. The soil level should now be 1 inch below the top of each pot.
5. Pour water in to the first pot so that half the soil is moist. *
6. Pour water into the 2nd pot until all the soil is moist and a little water comes out at the bottom. * Note: When you are watching for the water to come out of the bottom of the pot to show that all the soil is moist, be sure that it is not running down a space between the soil and the pot. If so, water a little, then wait for the soil to swell back to fill the pot.
7. Pour water into the third pot until water is flowing out of the bottom. *
8. Leave the plant alone so that the water can sink through.
9. Repeat steps 5-8 three times a day.
10. Construct a results table.
11. Record all observations about the plant and its growth in the results table on a daily basis. The observations should include the number of seeds that have germinated, plant height and observations about plant health such as color, the plant stability and condition of leaves. The number and size of leaves should also be monitored.
12. Keep all the pots in the same setting to minimize any variation in temperature, lighting, and other environmental factors, i.e. do not move the plants from their original position to maintain the controlled variables.

*It is important to add the water to the pot slowly so that it can properly soak into the soil.
** This is a draft aim and hypothesis, I still need to work on them I think x)

Discussion of Method:
The independent variable in this experiment is the amount of water used.
The dependent variables are the plants growth and health.
There are also many controlled variables such as the radish seeds, the type and amount of soil, the sunlight and temperature.

The 3 plants are in the same place all within 50 cm of each other. This is to control the amount of sunlight reaching the plants and the temperature each plant is in as controlled and constant as possible.

All three plants have been planted in the same soil which limits variation and ensures equality.

I have also chosen to use seedlings instead of young plants to enforce further control over the experiment. The problem with buying 3 pre planted plants for this experiment is that you have no control or much knowledge really before they were in your possession. So, I would have had no control on the amount of water and sunlight each had received prior to buying them or over the variation in how each had been grown. Also the plants may have been planted at different times meaning one is older than another and they may have suffered from a disease that I wouldn’t know about which could cause variation in the experiment.

I chose radish seeds because they grow quickly and thrive in cooler weather. They are also very well suited to containers as well as in the ground and very few disease effect radishes in their short growth cycle.