TMSCA #12

Juanita and Olivia set up an experiment to test the viscosity of different liquids. They gathered 10 identical graduated cylinders (100 ml). The girls filled the cylinders with 10 different liquids to the 80 ml mark and then one at a time, dropped a small metal ball in the cylinder. They then measured the time it took for the ball to drop to the bottom of the cylinder to the nearest hundredth of a second. The results of their experiment are in this chart.

What liquid type had the highest viscosity?

• cylinder J

• cylinder H

• cylinder A

• cylinder E

What could the girls have done to make their experiment have more reliable data?

• Have different people time the ball dropping for each liquid.

• Round the times off to the nearest second to make it easier.

• Try dropping the ball different ways each time.

• Repeat the experiment to have multiple trials.

Halfway through the experiment, Olivia’s mom said it was time for lunch. The girls put the cylinders in the refrigerator while they went to go eat lunch. When they returned, they finished timing the rest of the balls dropping in the cylinders. Doing this could change or cause a problem with their experiment?

• No, this will not change the results of their experiment at all.

• Maybe, there is no way to tell so it should be OK.

• Yes, viscosity can be affected by change in temperature. They should start over and keep the temperature the same for all the cylinders.

• No, it was a good idea to put the cylinders in the refrigerator so the perishable liquids would not spoil while they were at lunch.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

NGSS.MS-PS3-5

Olivia noticed that one of the cylinders was taking a lot longer than the others for the ball to drop through it. She decided to cover the top and then shake up the liquid to see if that would change the time. It did! The ball dropped must faster after she shook the cylinder. What is a reasonable explanation to why this happened?

• When Olivia shook the cylinder, she caused the molecules in the substance to move slower which also caused the ball to move faster.

• When Olivia shook the cylinder, she caused the liquid to have a chemical reaction which changed the substance and therefore, changed its viscosity.

• When Olivia shook the cylinder, she caused a stress called “shear thinning” which lowered the viscosity of the fluid.

• When Olivia shook the cylinder, some of the liquid squirted out and thus changed the viscosity of the fluid.

What is a low-lying landform that is created by deposition of sediment that was carried there by a river when it flows into a larger body of water?

• aquifer

• delta

• water table

• tributary

Tags

NGSS.MS-ESS2-2

In a forest, after a heavy storm, the forest floor is often covered with loose material from the natural breakdown of fallen leaves and branches. This material, which is in the early stages of decay, is known as what?

• detritus

• delta

• hypoxia

• halophyte

Tags

NGSS.MS-LS2-3

Consider a lake that has recently experienced a significant increase in pollution levels. Scientists are monitoring a particular species in the lake that is known for its sensitivity to pollution changes. This species' population changes are helping scientists understand the extent of pollution. What is this species called?

• indicator species

• invasive species

• keystone species

• all of these

Tags

NGSS.MS-LS2-4

During a biology class, a teacher explains that normally, human beings have a total of how many chromosomes?

• 48 chromosomes

• 24 pairs

• 46 chromosomes

• both A and B

In a large greenhouse, which part of the tomato plants directly facilitates the conversion of sunlight into chemical energy?

• vacuole

• chloroplast

• cell wall

• cell membrane

Tags

NGSS.MS-LS1-6

Imagine you are a scientist studying cell structures. You are focusing on a specific organelle located within the nucleus, known for its crucial role in synthesizing ribosomes. What is this organelle called?

• mitochondrion

• nucleolus

• nuclear membrane

• proteins

Tags

NGSS.MS-LS1-2