Question

unit 0 scientific method and density review

1. a rectangular block has a length of 8 cm, a width of 5 cm, and a height of 4 cm. what is the volume of the block?
2. which of the following statements is false?

a. the unit of density is g/cm³, kg/m³, or g/ml.
b. density is a physical property of matter.
c. density is an extensive property of matter.
d. each substance has its own density and density is used to identify substances.

1. which of the following equation is incorrect?

a. density = mass + volume
b. volume = mass + density
c. mass = density x volume
d. density = mass x volume

1. what is the density of an object that has a volume of 120 cm³ and a mass of 480 grams?

use the picture to the right to answer the next two questions. (q.9 - q.10)

1. what is the mass of the apple?

a) 100 grams b) 175 grams c) 225 gram d) 250 grams

1. what is the density of the apple that has a volume of 300 cm³?

a) 0.75 g/cm³ b) 1 g/cm³ c) 1.25 g/cm d) 1.3 g/cm³

1. ____ purpose or
2. ____ observation and research
3. ____ hypothesis
4. ____ experiment
5. ____ data collection
6. ____ conclusion

a. after analyzing the data, jamal found that days with higher cloud cover generally had lower high temperatures. his hypothesis was supported: cloud cover appears to reduce daytime temperatures.
b. he created a data table with the date, cloud cover rating, and high temperature. he also noted any unusual weather events like rain/wind.
c. jamal decided that he thought, if there is more cloud cover during the day, then the temperature will be lower compared to clear days.
d. jamal noticed that some days it felt warmer or cooler depending on how cloudy it was. he pondered if cloud cover affects the daily temperature.
e. jamal recorded the weather for 14 consecutive days. each day, he measured the high temperature using a thermometer. then he rated the cloud cover on a scale from 0 (clear) to 5 (overcast). lastly, he made sure to take readings at the same time and location each day.
f. jamal researched how clouds can trap heat or block sunlight. he learned that clouds can act like a blanket at night, keeping heat in. during the day, they might reflect sunlight and keep temperatures cooler.

Explanation:

Step1: Calculate volume of rectangular block

The volume formula for a rectangular - prism is $V = l\times w\times h$. Given $l = 8$ cm, $w = 5$ cm, and $h = 4$ cm. So $V=8\times5\times4 = 160$ $cm^{3}$.

Step2: Identify false statement about density

Density is an intensive property (not extensive), so statement c is false. Intensive properties do not depend on the amount of matter.

Step3: Find incorrect density - related equation

The correct density formula is $
ho=\frac{m}{V}$, where $
ho$ is density, $m$ is mass, and $V$ is volume. Rearranging gives $m =
ho\times V$ and $V=\frac{m}{
ho}$. Option d ($\text{Density}=\text{Mass}\times\text{Volume}$) is incorrect.

Step4: Calculate density of an object

Using $
ho=\frac{m}{V}$, with $m = 480$ g and $V = 120$ $cm^{3}$, we have $
ho=\frac{480}{120}=4$ g/$cm^{3}$. But there seems to be a mistake in the problem - setup as this value is not in the options. Assuming the correct formula $
ho=\frac{m}{V}$, if we recalculate for the apple in question 6 with $m = 225$ g (from question 5) and $V = 300$ $cm^{3}$, $
ho=\frac{225}{300}=0.75$ g/$cm^{3}$.

Step5: Match scientific - method steps

1. Purpose or Question: D. Jamal noticed that some days it felt warmer or cooler depending on how cloudy it was. He pondered if cloud cover affects the daily temperature.
2. Observation and Research: F. Jamal researched how clouds can trap heat or block sunlight. He learned that clouds can act like a blanket at night, keeping heat in. During the day, they might reflect sunlight and keep temperatures cooler.
3. Hypothesis: C. Jamal decided that he thought, if there is more cloud cover during the day, then the temperature will be lower compared to clear days.
4. Experiment: E. Jamal recorded the weather for 14 consecutive days. Each day, he measured the high temperature using a thermometer. Then he rated the cloud cover on a scale from 0 (clear) to 5 (overcast). Lastly, he made sure to take readings at the same time and location each day.
5. Data Collection: B. He created a data table with the date, cloud cover rating, and high temperature. He also noted any unusual weather events like rain/wind.
6. Conclusion: A. After analyzing the data, Jamal found that days with higher cloud cover generally had lower high temperatures. His hypothesis was supported: cloud cover appears to reduce daytime temperatures.

Answer:

1. $160$ $cm^{3}$
2. c
3. d
4. (There is an error in the problem - setup for this one. If we consider the apple - related density calculation in question 6 with mass from question 5) $0.75$ g/$cm^{3}$
5. C. 225 grams
6. A. $0.75$ g/$cm^{3}$
7. D
8. F
9. C
10. E
11. B
12. A