energy and electricity and purification Flashcards
Nuclear energy
energy stored in an atom
electron
subatomic particle which flows in a circuit carrying a negative charge
firing a bow and arrow…
elastic potential energy (decreases in the bow and increases kinetic energy in the arrow)
electromagnet
current, core, coils
- if you pass electricity through a coil of wire, the coil acts like a magnet - there is a magnetic field around it.
- If you put a magnetic material such as an iron nail into the centre, the magnetic field gets even stronger
*You have made a magnet using electricity!
current
A measure of the flow of electrons at a point per second in series - measured in amperes (amps).
*An ammeter is used to measure the current
Unit = amperes (amps) (A). Measured with an ammeter with symbol
–(A)– (circle around the A)
Conductor (electrical or thermal)
A material that allows charge or heat to flow easily through it
When heat flows through a material, the energy is transferred by vibrating particles in the susbtance.
Insulator (electrical or thermal)
a material that does not allow charge or heat to pass through it easily
Ohms
The unit of electrical resistance
Describe how energy stores change in particular situations
- Car on a ramp: gravitational as move up, converted to kinetic as roll down.
*Bunsen burner: fuel has the chemical energy store converted to thermal once lit
- Pair of magnets: same colours repel –> the magnetic store increased. As you let go, kinetic store increases
Pendulum: a pendulum is pulled to the side. Its height from the ground increases. –> The gravitational store increases, when you let go, kinetic store increases.
WHAT energy store increases when you stretch a rubber band?????
ELASTIC POTENTIAL ENERGY.
FILL IN THE GAPS:
The electric current —- energy from one ——— to ——–.
1)transfers
2)store
3)another (accept anything corresponding with dis)
FILL in da the gaaaapppaaaaaaaaaaaaaaaaaassssssssss:
The ——– current into a ————– = the ——— current out.
1) total
2) junction
3) total
We measure current with an ———-
1) ammeter
CAN U BUILD A CURCUIT FROM A CIRCUIT DIAGRAAAAAAM??
Wot u think?? > 3
DRAW A CIRCUIT DIAGRAM
ask ur muther 4 papier
remember da ruler
write the circuit symbols for a :
wire
battery
switch
in series
in parallel
voltmeter
bulb/lamp
ammeter
cell
LED
buzzer
motor
look on papier
Can you read an ammeter correctly?
TRY
how do you increase the strength of an electromagnet?
- increase the number of turns on the coil of wire
- increase the battery voltage
can you write methods for a well controlled experiment?
DO it
can you draw a results table?
yes.
Can you identify independent, dependent and control variables?
independent – what you are changing
dependent– what you are keeping the same
control– what you are measuring
Describe an experiment to compare the chemical energy stores in different fuels? (e.g. burning fuels)
To compare the chemical energy stores in different fuels, an experiment using calorimetry can be conducted.
This involves burning each fuel under a known amount of water and measuring the temperature increase. The greater the temperature increase, the more chemical energy the fuel originally contained.
Equipment:
6 boiling tubes
Retort stand and clamp
one test tube rack
20cm3 syringe
thermometer
wooden handled needle or metal tongs
balance scales
weighing boats
food items (Monster munch, popcorn, mini marshmallows, jelly babies)
Method:
1. Measure 10cm3 of water into a boiling tube
2. Clamp the boiling tube in the retort stand at an angle as shown in the diagram and over a heat resistant mat.
3. Weigh a small piece of food and record the mass
4. Take the temperature of the water and record it.
5. Fit the food at the end of the mounted needle (or hold it in the tongs).
6. Ignite the food using a bunsen burner and immediately hold it 1cm below the test tube (and above the head resistant mat). If the flame goes out, quickly relight it.
7. When the food stops burning, stir the water with the thermometer and record the temperature.
8. Reweigh any food left on the needle (in the tongs), and record the mass remaining.
9. Repeat the experiment using a new boiling tube with the same amount of water and a different food item.
10. Calculate the temperature increase per gram of food burned using the calculation below:
change in temp (water) (divided by) change in mass (food)
- Compare:
Compare the energy released per gram of fuel for each fuel to determine which fuel has the highest chemical energy store.
Fair Testing:
Same amount of water: Ensure the same volume of water is used for each experiment to avoid bias.
Same starting temperature: Ensure the water starts at the same initial temperature for each experiment.
Same conditions: Conduct all experiments in the same environment and under similar conditions to minimize external factors.
Identify electrical conductors and insulators
Create a circuit with a battery and an ammeter, with a gap where you will place different materials to determine if the electrical charge passes through them (conductors) or not (insulators)
Conductors, which allow the current to flow, will lead to a ammeter reading. Insulators will not allow the current to flow, or only at a very low rate, so the ammeter will either not have a reading or have a very low reading.
Conductors include metals such as wire, coins, paper clip but also a pencil as the graphite allows the current to flow through it.
Insulators include paper, a rubber, plastic, mirror, glass.
Plastic is an insulator so this is why wires are often coated in plastic to protect from electric shocks.
Quantifying the conductivity of different materials (using ammeter)
Create a circuit with a battery and an ammeter, with a gap where you will place different materials to determine if the electrical charge passes through them (conductors) or not (insulators). Take measurements of how many amperes are recorded by the ammeter for each material. Compare and contrast the readings to determine which materials have higher or lower levels of conductivity. Remember that the ammeter must be connected in series.
Conductors, which allow the current to flow, will lead to a ammeter reading. Insulators will not allow the current to flow, or only at a very low rate, so the ammeter will either not have a reading or have a very low reading.
