P6 - Matter, Models and Explanations Flashcards
How can we show the universe is expanding, and how does this help our understandings of the past?
Red-shift, wavelength distance → visible light, distant = red. Galaxy movement (red-shift), universal expansion proof. Big-bang, small hot region. Expanded out.
How is the practical measuring a spring’s extension and work done on it performed?
Extension:
- Clamp stand hangs spring (with hook)
- Measure spring length
- Add weights to hook
- Extension, new length - original length
Work done:
- Force-extension graph (area = work done)
What is the practical for measuring specific heat capacity?
- Measure substance mass
- Place thermometer, electric heater (connected to joulemeter), solid / liquid in container
- Record energy on joulemeter when temperature increases.
How do orbits work and how are astronomical objects formed?
Orbits, closer gravitational force, greater acceleration. Changing velocity (direction), but unchanging speed. Speed change, radius change. Formation, gravitational dust / gas collisions. Higher pressure → particle speed → temperature. Sun, fusion reactions, collision / expansion equilibrium.
How does pressure work in fluids and how does atmospheric pressure work?
Fluids, force normal to surface. Gases, compressions / expansions. Net force 90° to surfaces. Increasing volume, decreasing pressure / collisions. Atmospheric, air’s weight, differing molecule number. Depth, above accumulated weight, upthrust force, density.
How does elastic / plastic deformation differ?
Stretching / bending / compressing, 2+ force(s) required. Elastic (reversible) / plastic (irreversible) deformation, particle separation changed.
What is density and specific heat capacity / latent heat?
Density, measures closely-packed particles. Heating, particles gain energy, vibrate more (kinetic). SHC, energy required raising 1kg of material by 1°C. SLH, energy required changing state of 1kg of material, without temperature change.
