Grade 8 : Science (Curiosity) - Investigative Science (Set 1) | Concept of Maths

Question 1

1. In an experiment to see how the amount of sunlight affects plant growth, what is the independent variable?

A) The height of the plant

B) The amount of sunlight

C) The type of soil used

D) The amount of water given

Answer

Correct Answer: B

The independent variable is the factor changed by the investigator. In this case, the amount of sunlight is deliberately varied.

Question 2

2. A student measures the length of a rod three times and gets $12.1\text{ cm}$, $12.2\text{ cm}$, and $12.0\text{ cm}$. The actual length is $15.0\text{ cm}$. These measurements are:

A) Accurate and precise

B) Accurate but not precise

C) Precise but not accurate

D) Neither accurate nor precise

Answer

Correct Answer: C

The measurements are close to each other (precise) but far from the true value of $15.0\text{ cm}$ (not accurate).

Question 3

3. Which of the following is a quantitative observation?

A) The liquid has a volume of $250\text{ mL}$

B) The solution turned bright blue

C) The gas produced a pungent smell

D) The solid felt rough to the touch

Answer

Correct Answer: A

Quantitative observations involve numerical values and measurements. $250\text{ mL}$ is a specific quantity.

Question 4

4. If a car travels a distance $d = 100\text{ m}$ in time $t = 5\text{ s}$, what is its speed $v$ using the formula $v = \frac{d}{t}$?

Question 5

5. What is the purpose of a 'control' in a scientific investigation?

A) To make the experiment run faster

B) To provide a standard for comparison

C) To change multiple variables at once

D) To ensure the result is always positive

Answer

Correct Answer: B

A control is used to ensure that the observed effect is actually caused by the independent variable being tested.

Question 6

6. A student measures the mass of an object as $45.2\text{ g}, 45.4\text{ g}, 45.3\text{ g}$. Calculate the mean mass.

A) $45.2\text{ g}$

B) $45.4\text{ g}$

C) $135.9\text{ g}$

D) $45.3\text{ g}$

Answer

Correct Answer: D

Question 7

7. On which axis of a graph should the independent variable usually be plotted?

A) The x-axis (horizontal)

B) The y-axis (vertical)

C) The z-axis

D) The diagonal axis

Answer

Correct Answer: A

Conventionally, the independent variable (cause) is on the x-axis and the dependent variable (effect) is on the y-axis.

Question 8

8. Convert $1.5\text{ kilometers}$ into $meters$.

A) $15\text{ m}$

B) $150\text{ m}$

C) $1500\text{ m}$

D) $15000\text{ m}$

Answer

Correct Answer: C

Question 9

9. Which of these is a properly written scientific hypothesis?

A) I think plants like water.

B) If the temperature increases, then the rate of reaction will increase.

C) Why do birds fly south?

D) The experiment was successful.

Answer

Correct Answer: B

Question 10

10. An error that occurs when a weighing scale is not set to zero before use is called:

A) Random error

B) Human error

C) Rounding error

D) Systematic error

Answer

Correct Answer: D

A systematic error (like a zero error) shifts all measurements by the same amount in the same direction.

Question 11

11. Calculate the percentage error if the experimental value is $9.0$ and the theoretical value is $10.0$.

A) $10\%$

B) $1\%$

C) $90\%$

D) $11.1\%$

Answer

Correct Answer: A

$$\% \text{ error} = \frac{|10.0 - 9.0|}{10.0} \times 100 = \frac{1.0}{10.0} \times 100 = 10\%$$

Question 12

12. What is the SI unit of thermodynamic temperature?

A) Celsius ($^\circ C$)

B) Fahrenheit ($^\circ F$)

C) Kelvin ($K$)

D) Joule ($J$)

Answer

Correct Answer: C

Question 13

13. If you have a dataset: $5, 8, 12, 15, 20$. What is the range?

A) $12$

B) $15$

C) $20$

D) $5$

Answer

Correct Answer: B

Question 14

14. A scientist wants to measure the volume of an irregular stone. Which method should they use?

A) Length $\times$ Width $\times$ Height

B) Weighing it on a balance

C) Water displacement in a graduated cylinder

D) Using a ruler to measure the diameter

Answer

Correct Answer: C

Water displacement measures the volume of irregular objects by observing the change in water level.

Question 15

15. Write $0.00045$ in scientific notation.

A) $4.5 \times 10^{-4}$

B) $4.5 \times 10^4$

C) $45 \times 10^{-5}$

D) $0.45 \times 10^{-3}$

Answer

Correct Answer: A

Question 16

16. To increase the reliability of an experiment, a scientist should:

A) Change two variables at once

B) Repeat the experiment multiple times

C) Use a larger font in the report

D) Only record the results they like

Answer

Correct Answer: B

Repetition and averaging results help reduce the impact of random errors and increase reliability.

Question 17

17. Which piece of equipment is most precise for measuring $12.5\text{ mL}$ of liquid?

A) $100\text{ mL}$ Beaker

B) $250\text{ mL}$ Erlenmeyer flask

C) $500\text{ mL}$ Plastic jug

D) $25\text{ mL}$ Graduated cylinder

Answer

Correct Answer: D

A smaller graduated cylinder has finer markings (increments), making it more precise for small volumes.

Question 18

18. If a line on a distance-time graph is a straight horizontal line, it means the object is:

A) Stationary (at rest)

B) Moving at a constant speed

C) Accelerating

D) Decelerating

Answer

Correct Answer: A

A horizontal line means the distance is not changing as time passes, so speed is zero.

Question 19

19. In the formula for density $\rho = \frac{m}{V}$, if mass $m = 50\text{ g}$ and volume $V = 10\text{ cm}^3$, what is $\rho$?

A) $0.2\text{ g/cm}^3$

B) $500\text{ g/cm}^3$

C) $5\text{ g/cm}^3$

D) $60\text{ g/cm}^3$

Answer

Correct Answer: C

Question 20

20. An 'inference' is:

A) Directly seeing something with your eyes

B) A logical explanation based on observations

C) A guess made without any evidence

D) The final measurement in an experiment

Answer

Correct Answer: B

Inferences go beyond the literal observation to provide a possible explanation for what was seen.

Accepted Answer

Correct Answer: C

Grade 8 : Science (Curiosity) - Investigative Science (Set 1) | Concept of Maths