10th grade working scientifically

Question 1

Study: Solubility of a salt in water. Temperature (°C) → Solubility (g per 100 g water) 0 → 12 20 → 24 40 → 36 60 → 48 80 → 60 At which value of “Temperature (°C)” was the lowest value recorded?

• A. 0
• B. 20
• C. 60
• D. 80

Question 2

Experiment 1: Seeds were kept at 10 °C, 20 °C and 30 °C, all watered daily, and the number that germinated was counted. Experiment 2: Seeds were kept at 20 °C and given 0, 5 or 10 mL of water a day. In Experiment 2, which variable was changed on purpose?

• A. the number of seeds that germinated
• B. the volume of water
• C. the temperature
• D. the colour of the pots

Question 3

Study: Solubility of a salt in water. Temperature (°C) → Solubility (g per 100 g water) 0 → 12 20 → 26 40 → 40 60 → 54 80 → 68 Estimate the value at 10, assuming the pattern between neighbouring points is a straight line.

Answer 

Question 4

Experiment 1: Seeds were kept at 10 °C, 20 °C and 30 °C, all watered daily, and the number that germinated was counted. Experiment 2: Seeds were kept at 20 °C and given 0, 5 or 10 mL of water a day. Which variable was kept constant in Experiment 2 but changed in Experiment 1?

• A. the temperature
• B. the volume of water
• C. the number of seeds that germinated
• D. the colour of the pots

Question 5

Hypothesis: "Plants grow faster in blue light than in red light." Which experiment tests it best?

• A. Identical plants under blue or red lamps of equal brightness, same water and temperature
• B. Different species under the same lamp
• C. Plants in blue light only
• D. One plant in blue light outdoors and one in red light indoors

Question 6

Study: Solubility of a salt in water. Temperature (°C) → Solubility (g per 100 g water) 0 → 12 20 → 18 40 → 24 60 → 30 80 → 36 How does “Solubility (g per 100 g water)” change as “Temperature (°C)” increases?

• A. It increases to a maximum, then decreases.
• B. It increases steadily.
• C. It decreases steadily.
• D. It stays about the same.

Question 7

Study: Stretching a spring. Force (N) → Extension (cm) 0 → 0 1 → 3.5 2 → 7 3 → 10.5 4 → 14 5 → 17.5 At which value of “Force (N)” was the highest value recorded?

• A. 0
• B. 2
• C. 3
• D. 5

Question 8

Experiment 1: A pendulum with a 0.5 kg bob was timed for 10 swings with string lengths of 0.25 m, 0.50 m and 1.00 m. Experiment 2: A 1.00 m pendulum was timed with bobs of 0.1 kg, 0.5 kg and 1.0 kg. In Experiment 2, which variable was changed on purpose?

• A. the temperature of the room
• B. the string length
• C. the mass of the bob
• D. the time for 10 swings

Question 9

Study: Cooling coffee. Time (min) → Temperature (°C) 0 → 84 5 → 74 10 → 64 15 → 54 20 → 44 Estimate the value at 12.5, assuming the pattern between neighbouring points is a straight line.

Answer 

Question 10

Experiment 1: Seeds were kept at 10 °C, 20 °C and 30 °C, all watered daily, and the number that germinated was counted. Experiment 2: Seeds were kept at 20 °C and given 0, 5 or 10 mL of water a day. Which variable was kept constant in Experiment 2 but changed in Experiment 1?

• A. the colour of the pots
• B. the number of seeds that germinated
• C. the temperature
• D. the volume of water

Question 11

A scientist tests a new fertiliser on 20 tomato plants. Another 20 plants get no fertiliser. What is the purpose of the second group?

• A. It increases the dependent variable.
• B. It is not needed.
• C. It makes the experiment faster.
• D. It is a control group to compare against.

Question 12

Study: Cooling coffee. Time (min) → Temperature (°C) 0 → 87 5 → 77 10 → 67 15 → 57 20 → 47 How does “Temperature (°C)” change as “Time (min)” increases?

• A. It increases steadily.
• B. It increases to a maximum, then decreases.
• C. It decreases steadily.
• D. It stays about the same.

Question 13

Study: Light and pondweed. Distance from lamp (cm) → Bubbles per minute 10 → 52 20 → 46 30 → 40 40 → 34 50 → 28 At which value of “Distance from lamp (cm)” was the highest value recorded?

• A. 10
• B. 30
• C. 40
• D. 50

Question 14

Experiment 1: Magnesium ribbon was added to hydrochloric acid at concentrations of 0.5, 1.0 and 2.0 mol/dm³ at 25 °C, and the gas volume after 1 minute was measured. Experiment 2: The 1.0 mol/dm³ acid was used at 15 °C, 25 °C and 35 °C. In Experiment 2, which variable was changed on purpose?

• A. the colour of the magnesium
• B. the acid concentration
• C. the temperature
• D. the volume of gas after 1 minute

Question 15

Study: Cooling coffee. Time (min) → Temperature (°C) 0 → 88 5 → 78 10 → 68 15 → 58 20 → 48 Estimate the value at 2.5, assuming the pattern between neighbouring points is a straight line.

Answer 

Question 16

Experiment 1: A pendulum with a 0.5 kg bob was timed for 10 swings with string lengths of 0.25 m, 0.50 m and 1.00 m. Experiment 2: A 1.00 m pendulum was timed with bobs of 0.1 kg, 0.5 kg and 1.0 kg. Which variable was kept constant in Experiment 2 but changed in Experiment 1?

• A. the mass of the bob
• B. the string length
• C. the time for 10 swings
• D. the temperature of the room