Question 1

1. A scientist is testing how the concentration of salt in water affects the boiling point. If she uses 100 mL of water for every trial but changes the amount of salt from 5 g to 15 g, what is the independent variable?

A) The volume of water (100 mL)B) The boiling point of the waterC) The mass of the salt addedD) The type of thermometer used

Answer

✓ Correct Answer: Option C

Explanation: In a scientific experiment, the independent variable is the factor that the scientist intentionally changes. Here, the mass of salt (5g, 10g, 15g) is being varied to see its effect. The boiling point is the dependent variable.

Question 2

2. To measure the volume of a small, irregular stone, Rahul uses a displacement method. The initial water level in a graduated cylinder is 45.5 mL. After dropping the stone, the level rises to 62.3 mL. What is the volume of the stone?

$107.8cm^3$

Question 3

3. Two students measure the length of a desk. Student A gets 120.2 cm, 120.1 cm, and 120.3 cm. Student B gets 118.5 cm, 122.0 cm, and 119.5 cm. If the actual length is 120.0 cm, which statement is true?

A) Student A is more precise and more accurate than Student B.B) Student B is more accurate but less precise.C) Student A is more precise but less accurate.D) Both students have the same precision.

Answer

✓ Correct Answer: Option A

Explanation: Precision refers to how close measurements are to each other. Student A's values are very close (0.1 cm apart). Accuracy refers to how close a measurement is to the true value (120.0 cm). Student A's average is 120.2, which is closer to 120.0 than Student B's fluctuating values.

Question 4

4. A biological cell has a diameter of 0.000045 meters. How would a scientist express this measurement in scientific notation to make it easier to read?

A) $4.5 \times 10^{-4}m$B) $45 \times 10^{-6}m$C) $0.45 \times 10^{-4}m$D) $4.5 \times 10^{-5}m$

Answer

✓ Correct Answer: Option D

Explanation: To convert 0.000045 to scientific notation, we move the decimal point 5 places to the right to get 4.5. Thus, the exponent is -5. $$0.000045 = 4.5 \times 10^{-5}$$

Question 5

5. In a study of plant growth, a student records the following heights over 4 days: 2cm, 4cm, 8cm, 16cm. Which type of growth is this, and what is the likely height on Day 5?

A) Linear growth; 20 cmB) Exponential growth; 32 cmC) Constant growth; 18 cmD) Random growth; 24 cm

Answer

✓ Correct Answer: Option B

Explanation: The height doubles every day ($2 \times 2 = 4, 4 \times 2 = 8, 8 \times 2 = 16$). This is exponential growth. Following the pattern, the next value is $16 \times 2 = 32cm$.

Question 6

6. Why is "peer review" a critical part of the scientific world?

A) To make sure the scientist earns enough money from the discovery.B) To ensure that only famous scientists can publish their work.C) To allow other experts to check the experiment for errors, bias, or false data.D) To keep scientific secrets hidden from the general public.

Answer

✓ Correct Answer: Option C

Explanation: Peer review ensures the integrity of science. Experts in the same field evaluate the methods and logic to verify that the conclusions are supported by the evidence.

Question 7

7. An object has a mass of 250 grams and a volume of $50cm^3$. What is its density, and will it float in water (Density of water $= 1 g/cm^3$)?

A) $5 g/cm^3$; No, it will sink.B) $0.2 g/cm^3$; Yes, it will float.C) $5 g/cm^3$; Yes, it will float.D) $200 g/cm^3$; No, it will sink.

Answer

✓ Correct Answer: Option A

Explanation: Density is calculated as: $$Density = \frac{Mass}{Volume} = \frac{250g}{50cm^3} = 5 g/cm^3$Since5 > 1$ (density of water), the object will sink.

Question 8

8. Which of these is an inference rather than an observation?

A) The liquid in the test tube turned bright blue.B) The temperature of the water rose by $10^{\circ}C$.C) There are bubbles forming on the surface of the metal.D) The chemical reaction is producing a gas because bubbles are appearing.

Answer

✓ Correct Answer: Option D

Explanation: An observation is what you see (bubbles). An inference is a conclusion drawn from that observation (the bubbles mean gas is being produced).

Question 9

9. If you are measuring the length of a pencil with a ruler, why is it important to look at the scale directly from above (perpendicularly)?

A) To avoid zero error.B) To avoid parallax error.C) To increase the sensitivity of the ruler.D) To change the SI unit of the measurement.

Answer

✓ Correct Answer: Option B

Explanation: Parallax error occurs when the eye is not aligned directly with the measurement mark, leading to a slightly higher or lower reading than the actual value.

Question 10

10. A student measures the thickness of 50 identical sheets of paper together to be 5.5 mm. What is the thickness of a single sheet in micrometers (\mu m)? (1 mm = 1000\mu m)

A) 0.11 \mu mB) 11 \mu mC) 110 \mu mD) 1.1 \mu m

Answer

✓ Correct Answer: Option C

Explanation: First, find the thickness in mm: $$Thickness per sheet = \frac{5.5 mm}{50} = 0.11 mm$Now, convert to micrometers:$0.11 mm \times 1000 \mu m/mm = 110\mu m$$

Accepted Answer

✓ Correct Answer: Option B

Explanation: Using the displacement formula: $$V_{stone} = V_{final} - V_{initial}$$V_{stone} = 62.3 mL - 45.5 mL = 16.8 mL$Since1 mL = 1cm^3, the volume is16.8cm^3$.

Grade 6 : Science (Curiosity) - The Wonderful World of Science (Set 2)

1. A scientist is testing how the concentration of salt in water affects the boiling point. If she uses 100 mL of water for every trial but changes the amount of salt from 5 g to 15 g, what is the <b>independent variable</b>?

2. To measure the volume of a small, irregular stone, Rahul uses a displacement method. The initial water level in a graduated cylinder is 45.5 mL. After dropping the stone, the level rises to 62.3 mL. What is the volume of the stone?

3. Two students measure the length of a desk. Student A gets 120.2 cm, 120.1 cm, and 120.3 cm. Student B gets 118.5 cm, 122.0 cm, and 119.5 cm. If the actual length is 120.0 cm, which statement is true?

4. A biological cell has a diameter of 0.000045 meters. How would a scientist express this measurement in scientific notation to make it easier to read?

5. In a study of plant growth, a student records the following heights over 4 days: 2cm, 4cm, 8cm, 16cm. Which type of growth is this, and what is the likely height on Day 5?

6. Why is "peer review" a critical part of the scientific world?

7. An object has a mass of 250 grams and a volume of $50cm^3$. What is its density, and will it float in water (Density of water $= 1 g/cm^3$)?

8. Which of these is an <b>inference</b> rather than an <b>observation</b>?

9. If you are measuring the length of a pencil with a ruler, why is it important to look at the scale directly from above (perpendicularly)?

10. A student measures the thickness of 50 identical sheets of paper together to be 5.5 mm. What is the thickness of a <b>single</b> sheet in micrometers (\mu m)? (1 mm = 1000\mu m)