Nature of Science 8th Grade

Jennifer wanted to study the effect of sunlight on plant growth. So she decided to expose 10 identical plants to various amounts of sunlight each day (2 hours, 3 hours, 4 hours, 5 hours, and 6 hours). After one month, she measured the weight of the plants. What was the control?

• Hours of sunlight

• Plant weight

• Type of plant

Jennifer wanted to study the effect of sunlight on plant growth. So she decided to expose 10 identical plants to various amounts of sunlight each day (2 hours, 3 hours, 4 hours, 5 hours, and 6 hours). After one month, she measured the weight of the plants. What was the independent variable?

• Hours of sunlight

• Plant weight

• Type of plant

Marcus is completing a science experiment for class. He wants to see what effect water temperature has on plants. If his experiment contains one independent variable, which of the following would NOT be a constant in his experiment?

• The type of plant used

• The water temperature

• The room temperature

• The pot used for the plants

Suppose you want to find out if the amount of salt added to milk affects the growth of bacteria. So, you add different amounts of salt to 5 samples of milk that have been poured into 2 ounce plastic containers. Which graph should you use to communicate your results?

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Justin believes that the temperature lowering during the fall months is what causes the color of the leaves to change. He sets up an experiment wherein he placed some plants in 80 degrees rooms and some in 60 degree rooms. He then observed the color of the leaves for a total of 1 month. At the end of the month Justin observed that ¾ of the plants in the 60 degree temperature had been to change colors and only ¼ of the plants in the 80 degree temperature began to change colors.

What is the independent (test) variable?

• The temperature of the room

• The color of the leaves

• How long he lets the plants grow

• The type of plant that Justin uses

Ludnie wants to know if the amount of sugar in a cookie changes how fast the cookie will bake. She decides to set up an experiment to test this by changing the amount of sugar and measuring how long it takes for the cookies to become golden-brown.

What is the dependent (outcome) variable?

• The color of the cookie

• The time it takes for the cookies to bake

• The type of oven used

• The amount of sugar used

Other scientists following your procedure to complete an experiment is an example of _____________.

• Replication

• Repetition

• Recitation

• Redundancy

Whether paint is oil-based or water-based could determine how long it takes to dry. Liliana found two pieces of the same kind of pine wood and painted one with oil based blue paint and the other with water-based blue paint. Then she timed how long it took for each piece to dry.

What is a constant in the experiment?

• her hair color

• oil-based or water-based paint

• drying time

• kind of wood

These involve numbers, or an amount. Seeing that you have 2 text messages on

your phone is a(n):

• observation

• inference

• qualitative observation

• quantitative observation

These involve descriptions that cannot be expressed with numbers. Noticing that a bike is blue or that a grape tastes sour are examples of a(n):

• observation

• inference

• qualitative observation

• quantitative observation