Variables and Hypothesis Review

Variables and Hypothesis Review

Practice with components of scientific investigations

Variables

• The Independent variable (IV) is the factor that the investigator changes

• The Dependent variable (DV) is the factor that changes in response to the IV

• The constants are the factors that are kept the same

Multiple Choice

What is the IV in this question: How does the distance from an eye chart affect the number of letters that are recognized on a line

• The eye chart

• The distance from the eye chart

• The line

• The number of letters recognized

Multiple Choice

Amari wants to test the effect of the amount of light energy on plant growth. What is the dependent variable?

• Type of plant

• Plant container

• Amount of light

• Plant growth

Multiple Choice

Kay wants to determine if the length of the string affects the number of times a pendulum will swing back and forth in 10 seconds? What is the IV and the DV

• IV: pendulum, DV: number of seconds

• IV: length of string, DV: times the pendulum swings

• IV: times the pendulum swings, DV: number of seconds

• IV: length of string, DV: number of seconds

Hypothesis

A hypothesis is a suggested solution to a problem
Written as an "If... then... " statement

Example: If the amount of water given a plant is increased, them the plant will increase in height

Multiple Choice

Which is a valid hypothesis for this example: Ahleayah wants to investigate if the amount of fertilizer used on a field will affect the number of earthworms found there.

• If there are earthworms, then there will be fertilizer.

• If the amount of fertilizer is increased, then the number of earthworms will decrease

• Can earthworms live in fertilized fields?

• Fertilizer kills earthworms

Multiple Choice

What is a valid hypothesis for this example: Dante wants to investigate if the amount of oxygen in the water will have an effect on the oyster population.

• If the amount of oxygen in the water is decreased, then the number of oysters will decrease.

• Can oysters breathe oxygen in the water?

• Oysters will turn blue when exposed to oxygen.

• If there are oysters in the water, then there will be less oxygen.