Unit 1 Study Guide Review

A farmer decided to see if using a new type of fertilizer would increase his apple tree's yield. He applied the new fertilizer to one section of his orchard and left the other section untreated. The trees in the fertilized section produced twice as many apples!

What is the independent variable for this experiment?

• The amount of fertilizer

• The number of apples

• The type of apples

• The location of the apple trees

Answer explanation

The independent variable in an experiment is the factor that the experimenter manipulates or changes to see if it has an effect on the dependent variable. In this question, the farmer changed the amount of fertilizer on one section of his orchard to see if it would affect the yield of apples. Therefore, the independent variable is the amount of fertilizer.

A farmer decided to see if using a new brand of fertilizer would help his apple trees yield more apples. He applied the new fertilizer to one section of his orchard and left the other section without the new fertilizer. The section with the new fertilizer produced twice the number of apples!

What is the dependent variable for this experiment?

• The amount of fertilizer

• The number of apples

• The type of apples

• The location of the apple trees

Answer explanation

In an experiment, the dependent variable is the one that is observed for changes or response to the changes in the independent variable. In the question, the farmer changed the type of fertilizer (independent variable) and observed for changes in the number of apples produced (dependent variable). Hence, the number of apples is the dependent variable.

In a cold winter day, you notice that the water in the lake has frozen. Which state of matter that the water has transformed into has the lowest amount of energy?

• Solid

• Liquid

• Gas

• Plasma

Answer explanation

The question asks about the state of water which has the lowest amount of energy on a cold winter day when the lake has frozen. The correct answer is Solid. Water in the solid state, like ice, has the lowest amount of energy as the molecular movement is minimal.

Imagine you are studying different materials in your science class. Which state of matter, among the materials you are studying, would have the highest forces of attraction between its particles?

• A piece of wood (Solid)

• A glass of water (Liquid)

• Air in the classroom (Gas)

• Lightning in a storm (Plasma)

Answer explanation

The state of matter with the highest forces of attraction between its particles, as stated in the question, is a solid. In this case, a piece of wood is a solid. Solids have stronger intermolecular forces that hold their particles closely together, making them more compact and giving them a definite shape and volume, as compared to liquids, gases and plasma.

Imagine you're conducting an experiment in a lab with a sample of gas, and you're keeping the pressure constant. What would happen to the average kinetic energy of the gas particles if you increase the temperature of this gas in kelvin?

• It increases

• It decreases

• It remains the same

• It cannot be determined

Answer explanation

The average kinetic energy of gas particles is directly proportional to its temperature (in kelvin). This is based on the kinetic theory of gases. Therefore, if the temperature of the gas increases, the average kinetic energy of its particles also increases. This aligns with the correct option 'It increases'.

Imagine you have a piece of ice in your hand and it cools from 273 K to 263 K. What will happen to the average kinetic energy of its particles?

• It will increase

• It will decrease

• It will remain the same

• It cannot be determined

Answer explanation

The average kinetic energy of particles in a substance is directly related to its temperature. When the temperature of a substance decreases, as in this case where the ice cools from 273 K to 263 K, the average kinetic energy of its particles also decreases. Therefore, the correct answer to the question is 'It will decrease'.

Imagine you are studying the particles of a cup of hot coffee. What term would you use to define the measure of the average kinetic energy of these particles?

• Temperature

• Pressure

• Volume

• Density

Answer explanation

The question asks about the measure of the average kinetic energy of particles in a cup of hot coffee. Temperature is the correct term because it quantifies the average kinetic energy of molecules in any substance. This energy is related to how fast the molecules are moving. The other options, Pressure, Volume, and Density, don't measure the kinetic energy of particles.

Imagine you are in a room filled with different substances. You notice that the particles of these substances have spaces between them and are in constant motion. Which substance in the room would have the most space between its particles and would be moving at the greatest speed?

• A piece of wood (Solid)

• A glass of water (Liquid)

• The air around you (Gas)

• A neon sign (Plasma)

Answer explanation

In the question, the substance with the most space between its particles and the greatest speed of particle motion is being asked. Among the given options, air, which is a gas, has the most space between its particles. In comparison to solids and liquids, gases have particles that move at higher speeds due to increased kinetic energy.

How are the invention of the light bulb and scientific principles related?

• They are the same thing.

• The invention of the light bulb is a branch of scientific principles.

• The invention of the light bulb is the application of scientific knowledge.

• They are separate but related fields.

Answer explanation

The invention of the light bulb is related to scientific principles as it is an application of scientific knowledge. This means that scientific theories and principles were used to create, develop, and perfect this invention. It is not a branch of scientific principles, as the light bulb is a result, not a subset, of these principles.

A group of researchers are conducting a study on color preferences in infants. They propose the hypothesis “babies prefer the color orange”. Is this a good hypothesis? Explain.

• Yes

• No

• It depends

• Not enough information

Answer explanation

The answer is 'No'. This is because a good hypothesis needs to be specific and measurable. The hypothesis 'babies prefer the color orange' is too broad and unclear. It does not specify how preference is measured, or what age group of infants are being studied. It also assumes all babies would have the same preference, which is unlikely given the individual differences.