Speeding Past the School

Aim: See how many cars are speeding past school

Method:

1. Measure distance  ...  power pole 1 ⟶ power pole 2 = 59m
2. Time how long it takes a car to travel this distance
• "flag" person indicates when car passes the pole
• "timer" person starts when the car passes power pole 1 and stops when the car passes power pole 2
• "writer" person writes down the time
3. Collect 10 times
4. Calculate speed in m/s ⟶ convert to km/hr
5. Are there any speeders?

Results:

Speed	Car 1	Car 2	Car 3	Car 4	Car 5	Car 6	Car 7	Car 8	Car 9	Car 10	Average
Time (s)	2.55	2.89	2.39	3.12	2.15	2.74	2.85	2.89	3.38	3.39	2.83
m s-1	19.6	17.3	20.9	16	23.3	18.2	17.5	17.3	14.8	14.7	17.7
km hr-1	70.6	62.3	75.2	57.6	83.8	65.5	63	62.2	53.2	52.9	63

Conclusion:

As per the speed limit of the road, we can say according to the data that the cars are above the speed limit and are travelling too fast. The scenario that was given to us was:

The principal is worried about the speed of cars travelling past the school. From the principal's office, it appears that the cars are travelling too fast.

Our task was to calculate the average speed of the vehicles passing the front of the school using a stopwatch.

From the principal's hypothesis, we can say that the principal was correct, the limit speed of the road was 50kph and the cars were travelling an average of 63kph, which is a lot. We've also seen from the results that one car was travelling around 84 kilometres per hour in a 50kph road - which is too fast.

Drivers breaking school speed limits
Credit: Stuff

Questions:

1. What was the average speed of the cars that was measured?
• 63kph
2. Should the principal be worried about speeding on the road?
• Yes - because all cars measured were travelling more than the limit
3. Outline how you could improve this investigation and make it more accurate?
• Test it on more cars - the more cars, the more accurate.
• Using:
• Radar gun
• Technology - electronic timing system
• Speed cameras
• Rubber band on road

Voltmeter and Ammeter | Physics

1. When measuring volts it needs to be connected in parallel.
2. When measuring amps it needs to be connected in series.

Circuits

Voltage:

Voltage is the force from an electrical circuit's power source that pushes charged electrons (current) through a conducting loop, allowing them to do work such as light. 

Voltmeter:

Voltage is the number of electrons in a circuit. It is measured with a voltmeter. 

Current:

Is the number of electrons passing in a given point in one second.

Circuits | Physics

Activity: 

Go on to the PHET website and click on LAB: https://phet.colorado.edu/sims/html/circuit-construction-kit-dc/latest/circuit-construction-kit-dc_en.html

I want you to construct a few different circuits, try to make them and then take a screenshot of them and post the pic here.

1. A circuit containing a battery, a light bulb, connected by wires:

2. Now add a switch into the circuit you just made, what happens when the switch is open or closed?

3. Now click on the battery and increase the voltage it supplies to the circuit. What happened?

4. Underneath the switch there is an arrow, scroll through the options to the end and try putting some random things into the circuit like a coin or dog. What happens to light bulbs?

Circuit | Physics

Definition:

Cell

Supplies energy to circuit, by pushing current from the positive to negative end

Voltmeter

A device used to measure voltage, or electrical potential energy difference

Ammeter

A device used to measure current in a circuit

Wire

a thin, flexible thread of metal

Resistor

An electrical device that resists the flow of electrical current

Bulb

In a circuit, this shows if electricity is flowing by lighting up

Switch

a device that opens or closes a circuit

Battery

A device that converts chemical energy to electrical energy

Activity: 

Go on to the PHET website and click on LAB: https://phet.colorado.edu/sims/html/circuit-construction-kit-dc/latest/circuit-construction-kit-dc_en.html

I want you to construct a few different circuits, try to make them and then take a screenshot of them and post the pic here.

1. A circuit containing a battery, a light bulb, connected by wires:

2. Now add a switch into the circuit you just made, what happens when the switch is open or closed?

Electricity Circuits

There are two forms of circuits; Series and Parallel. 

Houses have Parallel circuits are found in houses. If one bulb blows out, then the rest of them are on.

Series Circuit
Credit: https://sites.google.com/site/lamsnc2dvella/Home/grade-9e-science/unit-3---electricity/series-and-parallel-circuit

Parallel Circuit
Credit: https://www.allaboutcircuits.com/textbook/direct-current/chpt-5/what-are-series-and-parallel-circuits/

Parallel

A circuit in which the bulbs are divided up evenly.

Series

A circuit in which the bulbs are in one continuous line.

Electricity | Physics

Van de Graaff generator generates static electricity.

We first looked at this video of static electricity by TedEd. 

Static Electricity

A build up of electrical charges on an object

Current Electricity

A flow of electric charge.

Electrical Charge

Electrical particles that are negatively charged

Circuit

A system that provides a pathway for electrical current to flow through

Cell

Supplies energy to circuit, by pushing current from the positive to negative end

Voltmeter

A device used to measure voltage, or electrical potential energy difference

Activity:

1 - Fill in the table

	Static electricity	Current electricity
What is it caused by?	When there is an imbalance between negative and positive charges within or on the surface of a material.	It can be generated when a moving metal wire through a magnetic field.
Do the negative charges move?	Yes	No
Does it power appliances?	No	Yes

Van De Graaff generator

2 - What are some examples of static electricity:

• Carpet

• Lightning

• Trampoline

• Hair

Write up for a Van der Graaff experiment:

How does the Van der Graaff machine work?

The Van der Graaff machine pulls electrons, moves them along a belt and stores them on the large sphere. These electrons repel each other and try to get as far away from each other as possible, spreading out on the surface of the sphere.

What was one of the experiments they did with the machine?

Putting your hand on the Van der Graaff machine and waiting for your hair to stick up. 

Describe what happened, what did you see?

After some time, the hair sticked up which looked cool. But, when the machine stopped then the hair goes back to normal.

Why did you see this happen?

The Eye - Conclusion

The Eye

Section 1: Label the diagram of the eye.

1. Sclera
2. lens
3. Iris
4. Cornea
5. Retina
6. Pupil
7. Optic Nerve

Quizlet: The Eye

Section 2: Complete the optical illusions and write down how you think each optical illusion works.

Optical Illusions

1. Young

2. Yes

3. Neither, both are the same size

4. Two faces and then see a white vase

5. Small is bigger

6. See three blocks of rectangle prism.

7. Can see white arrows going up and down and lines of black as well

8. A line with various arrows

9. A staircase

10. Blocks of rectangles

11. Two blocks

12. Various optical illusion triangle

13. One circle with another line dotted around and another circle where the dotted line is inside

14. Many shapes

Section 3: Find 10 interesting facts about the eye.

1. Your eye focuses on 50 different objects every second.   

2. Your eyes can see approximately 10 million different colours.

3. It is impossible to sneeze with your eyes open.

4. 80% of all learning comes through your eyes.

5. An average person blinks 12 times a minute.

6. The optic nerve contains more than one million nerve cells.

7. On average, you will blink approximately 4,200,000 times in a single year.

8. 80% of our memories are determined by what we see.

9. A blink typically lasts 100-150 milliseconds.

10. If the human eye was a digital camera, it would have 576 megapixels.

Interesting Facts

Section 4: Colour Blindness Eye test

Eye Test 

1. What are your colour blind test results?

2. Inconclusive

3. What does this mean?

4. Fine

5. What is normal colour vision?

6. It uses all three types of light cones correctly and is known as trichromacy.

Eye Dissection | Physics

Aim: To Dissect a cows eye and look at the different parts of the eye.

Equipment:

1. A cows eye
2. Scissors
3. Tweezers
4. Rubber Gloves

Before Dissection

Method:

1. Set up a treat with newspaper on the desk, the tray on top and the scissors and tweezers in the tray.
2. Put on a rubber glove.
3. Start to remove the excess fat and meat from around the eyeball before dissecting it.
4. Puncture a hole in the cornea where the cornea and the sclera meet.
5. Cut around the cornea so that the vitreous fluid leaks out of the eye onto the tray.
6. Once the cornea has been totally removed you will be able to remove the lens from the iris.
7. Cut the eye un half so that the inside is totally exposed. Once this has been done you will be able to access the retina at the back of the eye.
8. You should now have placed the retina, lens, cornea and iris on a piece of paper.
9. The dissection is not completed and all the parts of the eye need to be wrapped up and trashed. The trays and utensils that were needed must be rinsed and the rubber gloves thrown out.

Summary:

The cow's eye has exactly the same parts as the human eye except for its ability to see better in the dark.

After Dissection

The Eye | Physics

Yesterday, we looked at the eye and writing the purpose of that part of the eye. 

Part of eye	Purpose
Retina	The retina is located at the back of the eye, and when light hits the retina, it activates two types of cells, rods and cones. Rods identify light and dark and support images under dark and dim conditions. Cones are responsible for colour vision - red, green and blue, which detects a range of wavelengths, not the three specific colours.
Pupil	The size of the pupil determined by the iris, as the pupil gets bigger, as more light enters the eye.
Cornea	Light goes through the cornea, the transparent outer covering of the eye. Because the eyeball is round, the cornea acts as a lens, it bends or refracts light.
Optic Nerve	Where it sends light to the brain.
Iris	Light travels through the cornea and aqueous humour (helps to shape the cornea and provides nourishment to the eye.
Lens	Allows the eye to focus on either near and distant objects.
Vitreous humour	Is a clear watery gel that helps the eye and allows for this distance.