Dry Lab Activity

Unit A - Chapter 2

Investigating Science 9

Inquiry Activity

An Explosion of Life

Skills Reference 2

Skills you Will Use

  • Using appropriate equipment and tools
  • Drawing conclusions


  • Goggles
  • Apron


In this lab you will be dealing with aquarium water and algae.

Use goggles to protect your eyes and an apron to protect your clothes.

Fertilizers are often applied to fields and gardens to supply plants with nutrients, such as the elements nitrogen and phosphorus. However, this fertilizer can wash into local water and streams, resulting in high levels of nutrients in ponds and lakes. This can cause algae to grow much more rapidly than it normally would, a process known as eutrophication.

As the large amount of algae dies, it decomposes, removing oxygen from the water, which can cause animals in the water to die.

In this activity, you will investigate the affect of fertilizer on algae growth.


How does the amount of fertilizer affect algae growth?

Materials and Equipment

  • 4 jars with lids
  • aged tap water (this is water left open for a couple of days so that all chlorine evaporates)
  • graduated cylinder
  • felt marking pen
  • aquarium water, preferably with a small amount of algae suspended in the water
  • liqiud fertilizer

Dry Lab

A "dry lab" activity includes collected data and/or a video solution for your convenience. You can simply watch the following video and use the provided data, or if you wish to perform this lab for yourself, follow the procedure steps 1 through 6 described in the video. The same steps are included in written form in the documents available for download on the bottom of this page.

Forming Conclusions

  1. A student performing the procedure steps 1 through 6 found that the more fertilizer that was added to the water, the greater the amount of algae growth that resulted. Jar D, with the greatest amount of fertilizer added, showed the greatest amount of algae growth. Jar A, with no fertilizer, showed the least amount of algae growth. What do these results say about the affect of added fertilizer on aquatic ecosystems?

  2. Eutrophication is a huge problem in aquatic ecosystems in areas where chemical fertilizers are widely used. Suggest two solutions that might help avoid eutrophication, and explain why your suggested solutions might work.