Experiment Design

Students put two plants in the sun.  Plant A is in the sun for 10 minutes.  Plant B is in the sun for 1 hr.  Students decide that plant B is better at photosynthesis.  This is wrong because...

• They didn't control all variables
• The independent variable was sunlight
• The dependent variable was amount of gas produced
• they used different amounts of water

Tags

NGSS.MS-LS1-6

If you were testing how well different dish soap cleaned grease, the independent (experimental) variable would be the:

• Dishes
• Water
• Dish Soap
• Types of Grease

While PERFORMING AN EXPERIMENT, it is important to:

• change the control setup
• test many different variables at the same time
• reach a conclusion
• record observations and measurements

Changeable elements of an experiment which can affect the outcome of the experiment if not carefully controlled are called:

• placebos
• variables
• quantitative elements
• control groups

Tags

NGSS.MS-PS2-2

The number of variables that should be allowed to change in a well designed, controlled experiment is: 

• none
• 1
• 2 or more
• dependent on the type of experiment

Tags

NGSS.MS-PS2-2

Students are growing plants in the dark or in the light to see which grows better.  They put 3 seeds in the dark and 5 seeds in the light because they know seeds are more likely to dry out in the light. 
How could this experiment be improved?

• Put all plants in the light.
• Put all plants in the dark (where they sprout better)
• Put the same number of seeds in each container.
• put all the plants in the light so they grow better

Tags

NGSS.MS-LS1-5

NGSS.MS-LS2-1

Students experiment on wilting.  They take 2 plants of the same size.  They put one in full sunlight and leave one in the classroom.  After 2 hours, the plant in the sun has drooped.
Students conclude that sunlight causes wilting.  How could this experiment be improved?

• Do more trials.  Only 1 plant in each spot isn't much repetition.
• They should put both plants in the same location.
• They should leave the plants in the location for less time so the plant isn't hurt by the sun.
• They should make sure to water both plants first.

Tags

NGSS.MS-LS1-5

NGSS.MS-LS2-1

You start with a test tube of vinegar and a small container of baking soda.  If you mix baking soda and vinegar you get acetic acid and carbon dioxide.  (The carbon dioxide are the bubbles.)
What are the reactants of this reaction?

• baking soda and vinegar
• acetic acid and carbon dioxide
• the container you mix them in.
• how much bubbling there is.

During photosynthesis, carbon dioxide and water react to form oxygen and sugars.  For this reaction, the products are...

• carbon dioxide and water
• oxygen and sugars
• photosynthesis
• The leaves that are doing the reaction