7. A student wanted to see if the color of water impacted the increase in temperature, in degrees Celsius (°C), after 30 minutes in the Sun. Three beakers were filled with 50 milliliters (ml) of water,
and five drops of food coloring were added to each beaker. The beakers were then placed on a
window ledge in direct sunlight and temperature readings were
recorded every 10 minutes for 30
minutes
Red
Blue
Clear
0 min
22 °C
22 °C
TEMPERATURE OF WATER
10 min
20 min
25 °C
31 °C
25 °C
30 °C
25 °C
31 °C
30 min
32 °C
33 °C
33 °C
22 °C
What was the test (independent) variable in this experiment?
A. the color of the water
B. the temperature of the water
C. the amount of water in each beaker
D. the amount of time each beaker was exposed to sunlight