Science Fair Projects For Elementary School Students

These suggested science fair projects are suitable for elementary school students. They teach simple horticultural concepts with vegetable crops.

Project 1 - Tomato Seed Germination Rates
Project 2 - Effects of Different Fertilizer Solutions on Tomato Seedling Growth and Development in a Hydroponic System

Project 1. Title: Tomato Seed Germination Rates
Materials Needed: Tomato seeds, thermometer, small plastic plates, paper towels, plastic wrap.

Methods to Use:

• Prepare 9 germination plates by cutting paper towel circles to fit into the center of the plastic plates (or paper plates coated with plastic).

• Place 3 layers of paper towel circles into the middle of each plate and saturate the paper towel material with tap water (let excess water run off by tipping plate).

• Count out ten seeds and arrange them in a grid pattern on the wet paper towel material on each of the 9 plates.

• Cover the plates with plastic wrap to keep them from drying out.

• Place 3 germination plates with seeds on a warm window sill where the sun will warm them during the day (mark them "hot 1, hot 2, and hot 3" respectively).

• Place 3 plates in a shady spot in the coolest room of the house (mark them "cool 1, cool 2, and cool 3" respectively).

• Place three plates in the refrigerator (mark them "cold 1, cold 2, and cold 3" respectively).

Observations to Make:

• Record the date and time you started the trial.

• Take the temperature of the plates in each of the three temperature areas by sticking the thermometer under the plastic wrap and onto the paper toweling at both mid-day and late in the evening.

• Record the temperatures, times and dates when they were taken.

• Look at the plates each day and count the total number of seeds that have germinated.

• Record the number of seeds that have germinated each day for each treatment name and plate number.

• Consider that seeds have germinated when the radical (root) emerges from the seed about one-eighth of an inch.

Questions to Ask:

• Which temperature gave the earliest germination?

• Where would you put tomato seeds planted in small pots so that the transplants would grow the fastest?

• Might there be a reason to put them in a different area to slow them down or speed them up?

• How could you slow down or speed up tomato transplants in a greenhouse?

• Do the seedlings grown in the window sill look different than the ones grown in the cooler part of the house?

• Did the seedlings in the refrigerator ever germinate? Why or why not?

• Why use 3 plates instead of one? (Hint: all things in nature are variable).

Conclusions to Draw:

• Tomato seed germination is a bio-chemical process that is temperature dependent.

• Calculate the average days to germinate the tomato seeds in the three plates in each of the temperature areas.

• Graph the data that you obtained and try to draw a line to match the data points on the graph?

• Can you predict the days to germination at other temperatures?

Books at the Library: Look for basic books on plant growth and seed germination.

Materials Needed: Tomato seeds, small Styrofoam cups, clean sand, 2 or 3 types of garden fertilizers, 2 or 3 empty and clean one-gallon milk jugs. You can obtain small boxes of various types of soluble vegetable garden fertilizers from a nursery or home product store. Try to obtain one product that has nitrogen, phosphorous, potassium plus minor nutrients (like Miracle-Grow), a slow release formulation with nitrogen, phosphorous and potassium only, and a nitrogen only fertilizer.

Methods to Use:

• Prepare 12 planting cups by punching a small hole in the bottom of the cups and filling them two-thirds of the way full with clean sand.

• Mark each clean milk container with a caution label which states that it contains fertilizer and with the name of the type of fertilizer solution that it will contain (use a waterproof marking pen or pencil).

• Place one tablespoon full of fertilizer into the appropriately marked jug and fill the jug with tap water.

• Put 3 tomato seeds spaced about one-half inch apart in a line just under the surface of the sand in each planting cup.

• Mark 3 planting cups with a code name and number for each one of the 3 fertilizer solutions.

• For example the 3 Miracle Grow treatment cups might be marked "MG 1, 2 and 3 respectively.

• And mark 3 of the planting cups as negative controls (C1, 2, and 3 respectively) which will receive only pure tap water with no fertilizer added.

• Saturate the sand of each set of 3 planting cups with fertilizer solution from the appropriate jug of solution, or plain tap water in the case of the control set of 3 planting cups.

• The excess solution will drain out of the hole in the bottom of the cups and should be caught in a plate and returned to the appropriate fertilizer container.

• This process of saturating the sand should be carefully done each day.

• Avoid disturbing the surface of the sand and the placement of the seed by carefully and slowly pouring the solutions down the side of the cups.

• Make sure all of the cups are in an area where they will receive the same amount of sunlight and heat.

Observations to Make:

• Record the date and time you started the trial.

• Measure the height of the seedlings at weekly intervals.

• Observe the color, shape, and number of leaves on the seedlings grown with the different fertilizer solutions.

• Record your observations in a notebook for future use.

Questions to Ask:

• Which fertilizer makes the seedlings grow faster? Why?

• Would it be important to include a minor nutrients package if the plants were growing in soil?

• Could nutrient deprivation be used to slow down plant growth or hold transplants for a later use?

• Why use 3 cups instead of one? (Hint: all things in nature are variable).

Conclusions to Draw:

• Tomato seedlings require many nutrients that must all be supplied in a hydroponic solution production system.

• Calculate the average height of plants grown with the different fertilizer solutions.

• Graph the results recorded over a number of weeks.

• Can you draw some conclusions about how these different fertilizers could affect the yield of tomatoes from these different treatments?

• (Hint: Healthier transplants often lead to earlier first harvests and more total yield.)

Books at the Library: Look for books on hydroponics, gardening, and plant growth.