Experiment Design Sample Response

PLEASE NOTE: The GED Science Short Answer questions were discontinued at the beginning of 2018. Click here for our GED Science Practice Questions.

Here is a sample response to our Design an Experiment sample question. Review this response to see what a high-scoring GED Science short answer response looks like. This answer follows the template that is in our  Design an Experiment writing guide. Below this sample response is a commentary which explains why this would receive the top score of 3 points.

In order to test the hypothesis that mung beans will grow faster when watered with a caffeine solution, an experiment should be set up in the following manner. Take 20 pots filled with soil and 20 mung beans and plant each mung bean in the soil at approximately the same depth. The pots will them be divided into four groups: Control Group A, Group B, Group C, and Group D. Each group will have 5 pots.

The pots will be placed in a controlled greenhouse environment to ensure each pot receives the same amount of environmental light, heat, humidity, and other climate-related conditions. A watering can is filled to the top with water on Day 1, and Control Group A receives 2 inches of water. A caffeine tablet is then added to the water and allowed to dissolve before Group B receives 2 inches of water. Another tablet is then added and dissolved before Group C receives 2 inches of water. Finally, a third tablet is added and dissolved before Group D receives 2 inches of water.

Each day the process is repeated until germination occurs. The date and time of germination is recorded in a data collection table. After germination, the length of growth of each pot’s mung bean plant is carefully measured using the same tape measure. Water is continually added and the measuring continues on a daily basis until the plants have reached their maximum growth potential and begin to wither.

Once all the plants have either reached their full growth potential or withered, the experiment is over. The data is recorded on a scatterplot. The X axis represents the amount of caffeine given to each plant. The Y axis represents the rate of growth. The scatterplot is analyzed to see whether the plants given more caffeine grew at a faster rate in general than the plants given less caffeine, and all the plants are compared to the growth rate of the control group. If a direct correlation can be drawn between the amount of caffeine given and the increase in growth rate, then the hypothesis can be confirmed. However, if the data is inconsistent, or if the plants that received the most caffeine did not grow significantly faster than the control group plants, then the hypothesis can be disproved.


This is a 3-point essay. There are four main areas that were clearly explained:

  • The hypothesis (The first sentence clearly lays out the intention of the experiment by restating the goal of the prompt.)
  • The set-up of the experiment using the materials listed (Every item listed in the “materials” section is incorporated into the essay. The author did not leave any details out, and included other materials to expand the experiment, such as an acknowledgement of heat and humidity.)
  • A description of how data will be collected (The inclusion of a “data collection table” that tracked the specific rate of growth of each plant, as well as how often the data was to be collection helped clarify the experiment.)
  • An explanation for how the results will be interpreted to evaluate the hypothesis (The student introduced the idea of using a scatterplot to see if there was a strong correlation between the plants with the maximum caffeine and the growth rate.)

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