Ch1
A 13-year-old student is undergoing a rapid growth spurt and building muscle mass.
Proteins
Identify the three main subatomic particles. State the relative charge and mass of a proton, a neutron, and an electron.
Total Distance/total time
B. ExplanationDiffusion is driven by the net, passive movement of particles resulting from their random kinetic motion and collisions.
1b. Any two correct sources. Examples: Eggs, chicken/meat, fish, tofu, lentils, beans, nuts, cheese, milk. (Both must be correct for 1 mark).
1c.
Explain why an atom has an overall neutral electric charge even though it contains charged particles.
Look at the two scenarios below regarding a skateboarder on a flat road: [1]
An explorer weighing \(600\text{ N}\) walks across deep snow using wide snowshoes without sinking. Later, a person of the exact same weight steps onto the snow wearing sharp stiletto high-heeled shoes and sinks instantly.
Pressure is calculated as force divided by area (P=F/A). Both people exert the same downward force (weight of 600N). Snowshoes have a very large surface area, which spreads out the weight and results in low pressure on the snow, preventing sinking. Stiletto heels have an extremely tiny surface area, concentrating the entire 600N force onto a small point. This creates incredibly high pressure, easily breaking through the snow's surface.
Examine the clinical observation table below and answer the following questions:
Compare and Contrast: Early scientists used different models to describe the atom (such as Thomson's plum pudding model and Rutherford's nuclear model).
A student wants to investigate how the surface area of a parachute impacts the speed at which a toy drop-capsule falls to the ground. They cut out three square parachutes from plastic trash bags with side lengths of 10cm, 20cm, and 30cm. They drop each parachute from a school balcony 5 metres high and time the descent.
A teacher opens a bottle of ammonia at the front of a classroom. The pungent odor travels to the back of the room much faster when the classroom is heated to 30 degree celsius than when it is at 15 degrees celsius
Explain why burning coal for electricity harms the Earth more than using solar panels. Mention the greenhouse effect in your answer.
An experiment was conducted to find out the energy content per gram of three different food types by burning them under a test tube of water. The temperature change of the water was recorded below:
State which food sample contains the highest concentration of lipids (fats). Use the data from the table to justify your answer.
During the gold foil experiment, Rutherford's team recorded the following observational data:
Deduce what each of these three specific observations proved about the hidden internal structure of the atom.
The table below shows data collected by a group of students during a lab tracking the motion of a remote-controlled toy car moving along a straight track.
Calculate the average speed of the toy car over the entire 8-second trip. Show your formula and working out.
{Average Speed} = Total Distance/Total Time = 14meters/8seconds = 1.75 m/s.
Look at a scenario where a sealed syringe filled with air is pushed inward. The volume decreases, and the pressure gauge goes up.
Discuss how switching from coal to solar power affects local communities and the global climate. Use specific examples
Explain why a person with anemia experiences repeated or constant tiredness.
Anemia is the condition caused by lack of iron in the body. Less iron results in less hemoglobin. Reduced hemoglobin results in less blood transporting oxygen to the cells. Oxygen is necessary for respiration which releases energy for cell and the organism. Therefore the person with anemia has less energy and experiences repeated or constant tiredness.
Look at the transition from J.J. Thomson’s Plum Pudding model to Niels Bohr’s Planetary model. Explain why scientists must alter or completely discard a scientific model when new experimental data is collected.
Models are analogies based on available evidence. When new data contradicts an old model, the old model is proven insufficient. Scientists must change the model to accurately account for the newly discovered facts.
Modern car tires are manufactured with deep groove patterns called treads. Over time, these treads wear down and the tire surface becomes smooth.
Discuss how the wearing down of tire treads impacts road safety during heavy rainfall. In your response, explicitly address the relationship between surface texture and friction and explain how this scientific principle directly influences traffic safety regulations.
Smooth tires significantly reduce the surface texture roughness, lowering the overall frictional force between the rubber and the wet asphalt. This reduction in friction prevents the car from gripping the road efficiently. This demonstrates why governments must enforce strict legal limits on minimum tire tread depth to prevent high-speed collisions and ensure public transit safety.
A student wants to test how the surface area of a gas container affects gas pressure.
"All countries should stop using nonrenewable energy by next year." To what extent do you agree with this statement? Explain your view using scientific reasoning.
Disagree with the "by next year" timeline while agreeing with the ultimate goal.
Reasoning: Completely stopping nonrenewable energy in one year is unrealistic. Many countries lack the grid infrastructure, battery storage, and funding to switch instantly. A sudden stop would cause massive power blackouts and economic collapse. A gradual transition is necessary.