Students will test the claims of various forms of fertilizers to improve plant growth. Discuss how fertilizer works by giving plants large quantities of all the nutrients they need, including nitrogen, sulfur, phosphorus, calcium, potassium and magnesium. Have each student prepare a potted mung bean plant. Have students split into three groups, with each group using a different fertilizer. Place the pots in a sunny area and have students water them for five days, recording their growth before watering, to see which fertilizer works best.
Transpiration occurs when a plant loses water vapor. In this experiment, give students one of three full grown plants in pots: strawberry, tomato and lettuce. Have students make a hypothesis about which will release the most water vapor over three days. Students will make a tent with plastic wrap and sticks over each plant to collect the water transpired and collect data on the level of water for three days. You will generally find that the strawberry plant gives off the most vapor, because its water content was higher to begin with, which is what makes it taste juicier.
Students will split into five groups of three, each planting a different number of garlic chive seeds. The groups should plant two, five and 10 seeds. Students will record the growth level of their plants over the course of eight days. Students will find that the pots with less seeds grew slightly taller. This is because those with many seeds in the same pod had to compete, and each individual plant was only able to get a limited amount of nutrients from the soil.
For a change of pace from pure experiments, have students write a two-page research paper on a fruit. The paper should include a description of its internal structure, where it grows, what kind of animals eat it, what kind of nutrients it contains, its ideal growing conditions, the number and shape of its seeds, and at least three random or interesting facts about it. Students should also bring in a sample of the fruit that you can cut into piece to share with the class.