Walter learned in science class that different substances release heat at different rates. He decides to test this.

At home, Walter turns the oven to 200°F. He places three casserole dishes in it: one is made of metal, one is made of glass, and one is made of ceramic. He leaves them in the oven for an hour. He then removes them from the oven, places a single ice cube on each one, and times how long it takes the ice cube to melt.

In this experiment, what is the test variable (independent variable)?
A.
the material each pan is made of
B.
the volume of each ice cube
C.
the temperature of each pan
D.
the amount of time it takes for the ice to melt

Electromagnets coils of wire paper clips picked up 10 3 15 6 20 9 25 12 ms. owens' class was studying magnets. ms. owens showed her students how to make an electromagnet using a nail, a d-cell battery, and plastic coated wire. the students wrapped the wire around the nail and then attached the ends to the battery. when they were finished, they tested their magnets by investigating how many paperclips their magnets could pick up. they also tested whether they could increase the strength of their electromagnets by using more coils of wire. they recorded the class average of their results in the data table seen here. ms. owens asked her students to graph their data in a line graph. how should the students label the x-axis on their line graph? a) size of battery b) number of paper clips c) number of coils of wire d) strength of electromagnet