Do Plants Need Water?

3.9 based on 73 ratings

Updated on Jan 02, 2014

Grade Level: 3rd - 7th; Type: Biology

Objective:

Determine whether plants will grow if they are watered with various liquids.

The purpose of this experiment is to find out whether plants really need water to grow or whether they just need to be kept wet.

  • What is the purpose of a plant’s roots?
  • What types of nutrients do plants need in order to survive?
  • Why do plants need water?
  • What happens to a plant that does not get enough water?
  • How do plants create energy?

Plants need sunlight, nutrient rich soil and water to grow. Though the quality of the water has an effect on the plant’s health, there are many plants that are able to grow even when they are given water that is polluted or that has some salt content. Most plants are unable to grow out of water that is as salty as the ocean, though there are a few varieties that can. Water is not always in abundant supply, and when it comes down to making sure that people have enough to drink, sometimes plants are asked to go without. Farmers have turned to using brackish water, or water that has a low salt content, for their crops. Understanding what types of fluids plants can use can help scientists learn more about how to meet the needs of plants as well as people in times of draught.

  • Seeds (green bean seeds work well because they grow quickly and are hardy.)
  • 5 Containers
  • A marker
  • Potting soil
  • Milk
  • Juice
  • Cola
  • Sports Drink
  • Water
  • A measuring cup

  1. Label the containers, “Water/Control,” “Milk,” “Juice,” “Cola,” and “Sports Drink.”
  2. Fill the containers with potting soil.
  3. Plant three seeds in each of the pots as directed on the back of the seed package.
  4. Measure out ½ cup of water and give it to the plants in the “Water/Control” container.
  5. Measure out ½ cup of milk and give it to the plants in the “Milk” container.
  6. Measure out ½ cup of juice and give it to the plants in the “Juice” container.
  7. Measure out ½ cup of cola and give it to the plants in the “Cola” container.
  8. Measure out ½ cup of sports drink and give it to the plants in the “Sports Drink” container.
  9. Place the plants in a warm, sunny place outdoors or in a window.
  10. Repeat steps 4-8 every other day.
  11. Record the growth of the plants on a chart such as the one below.

PLANT GROWTH CHART

HEIGHT

Water 1

Water 2

Water 3

Milk 1

Milk 2

Milk 3

Day 1

Day 2

Day 3

Day 4

Day 5

PLANT GROWTH CHART

NUMBER OF LEAVES

Water 1

Water 2

Water 3

Milk 1

Milk 2

Milk 3

Day 1

Day 2

Day 3

Day 4

Day 5

Terms/Concepts: Germinate;Growth; Photosynthesis; Roots; Stems; Leaves; Flowers; Fruit

References:

Writer and educator Crystal Beran is rarely seen without a pen. Her adventures have brought her to four continents and her quest for answers has led her to discover more questions than she could fill all the pages with. She currently resides in Northern California, where she can be found sipping tea and writing books.

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