Experiments for Kids: Effecting Plant Growth

Welcome to another edition of Saturday Science! We’re back with some exciting experiments for kids. Science is a fundamental part of our household and shapes the rest of our learning for the week. Today, I want to share an old science experiment we did before we even started homeschooling. This experiment was conducted for my son’s science fair project when he was in second grade.

Effecting Plant Growth with Liquids

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Question/ Hypothesis

For this experiment, we wanted to explore the effects of various liquids on plant growth. The question we asked was: “How do different liquids, such as tap water, river water, salt water, carbonated water, and soda, affect plant growth?”

My son, Legoman, predicted that the plant given river water would experience the most growth.

Materials and Procedure

To conduct this experiment, we needed the following materials:

  • 6 plants of the same variety and roughly the same size
  • 6 different liquids (we chose tap water, river water, salt water, carbonated water, and soda, but you can use any liquids your child wants to investigate)
  • Planters
  • Ruler
  • Measuring cup
  • Journal and pencil for recording data

To set up the experiment, we planted each plant in individual pots and labeled each pot with the corresponding liquid it would be receiving over the next two weeks. We also labeled each liquid container to match the plants.

Plant Science Experiment Set Up

It’s important to teach children about constants (unchanging elements) and variables (what you are manipulating) in a science experiment. In this project, our constants were the type of plant used, the container, and the amount of liquid for each plant.

We measured the same amount of liquid and watered each plant with it. Initially, we used 1/4 cup of liquid for each plant, but this amount had to be adjusted later on. It’s worth mentioning that we measured each plant’s size at the beginning of the project to establish a baseline measurement. This would help us track the growth over time.


Every day, Legoman would grab his tray of plants, ruler, and liquids with excitement, ready to start the day’s work. On the first day, most of the plants hadn’t grown yet, but the one receiving salt water had started to wilt. I won’t reveal everything that happened throughout the experiment because I want you to discover it yourself!

What happens to plants with salt water

One important observation we made was that the pots we used didn’t allow for proper drainage. This meant we had to adjust the amounts and frequency of watering.


The results of this experiment were astonishing! I highly recommend trying this experiment, especially during this season. Although I couldn’t find a printable version of the science journal and project packet, I’d love to know if you’re interested in having one.

Legoman had a blast entering all his data into the computer and creating graphs for his science board.

Documenting Science Experiments for Kids

Visit these great bloggers for more fun Saturday Science experiments too:

  • Jelly Bean Science from P is for Preschooler
  • 25 Classic Science Experiments For Kids from Little Bins For Little Hands

So, what’s your favorite science activity? I’d love to hear from you! Connect with me on Facebook, Twitter, Google+, Pinterest, Instagram, or subscribe by email. I can’t wait to hear your ideas!