Integrated Science

House of Blue by nuttyxander on flickr

What is the difference between molecular and empirical formulae?  You need to find out.  Here is a set of practice questions on this topic.  7 emp form

This week we’ll do a lab where we determine the formula ofhydrated copper (II) sulfate by experimental methods.  Read the lab sheet: formula of hydrated copper sulfate

To help you practice, there are tons of great resources out there on the web.  I have selected 4.  They are listed here in order of increasing complexity.

1. Nice worked examples.  2.  Another worked example for you to click through to find the solution. 3. Worked examples with extra problems, answers given.  4.  Fairly lengthy explanation of how to perform calculations.

For some online practice, try this site.  And this worksheet has some excellent questions.  If you can do these you are all set!  Empirical and Molecular Formula Questions

tulip stems refraction by mikeyexists on flickr

All waves refract.  This means that they change speed as they travel from one medium to another.  For example, light waves travel faster in air than they do in water.  This means the pencil in the glass of water looks like the picture on the right.  For a full explanation of refraction, read this.  Hopefully you now understand the concept.  If not, ask this archer fish to explain it to you! Thanks to Mr Goodman for finding this model.

We will do a lab to investigate refraction of light as it passes through glass and perspex, and to determine the refractive indices of these substances.  You will be required to submit the data tables, calculations and graphs for this lab along with your conclusion and evaluation.  Refer to these rubrics closely: FINALRubric DCP FINAL Rubric CE

Here is the lab refraction of light snell’s law lab Grade 9 v2

Here is a refraction ppt by Mr. Highland refraction

wing mirror by Izzard on flickr

All waves are reflected when they hit a surface or barrier.  The angle at which the wave is reflected is not random, but predictable.  We will investigate angles of incidence (i) and angles of reflection (r) of light waves hitting a plane mirror and try to answer these questions about light and reflection:-

• Light travels in straight lines.  What evidence can you think of that shows this?
• What is a virtual image?
• What does laterally inverted mean?

This link gives some basic information to start with.  This one gives a bit more detail.

mole by Mick E. Talbot on flickr

We are going to step into some deep and sticky chemistry – and take a look at the term mole.  This is an important concept, so we’ll take it slow and steady.  This is a great resource to help us work our way through the topic.  Come back and revisit it often – until you feel you have a handle on it.  Practice, practice, practice!

More useful information here.  And you might like this presentation as well.

And this might help too!

Khan Academy: Figuring out the emperical formula

The distance between repeating parts of the pattern (the length of each single wave) is known as the wavelength (ג).  Wavelengths can be measured from anywhere to the next identical part of the wave.

Frequency is a measure of how often something happens in one second. The symbol of frequency is f and the units are hertz (Hz). The relationship between velocity, frequency and wavelength is:

Velocity (m/s) = frequency (Hz) x wavelength (m)

Light waves travel much faster than sound waves. The speed of a set of waves can be found by using information about the distance travelled and time taken or from information about the frequency and wavelength.

Distance, speed and time are connected by:

Speed (m/s)   =   Distance (m) / time (s)

Example An echo takes 1.5 s to reflect from the front wall of a school building 250m away. What is the speed of sound in air?

Distance for echo = 2 x 250 m = 500 m                                Time taken   = 1.5 s

Speed = distance/time = 500/1.5 = 333m/s

This method is practical at school only for the measurement of the speed of sound.

Example Capital Radio broadcasts throughout the London area using radio waves of frequency 1548kHz, travelling at 300000km/s. To what wavelength would you tune a radio to receive Capital programmes?

Speed   = 300000km/s = 300000000m/s                  Frequency = 1548 kHz (1 548 000 Hz)

Wavelength = speed/frequency  = 300 000 000/1 548 000 = 194 m

Using your knowledge of the wave equation, and the relationship between frequency and time [f = 1/T], answer the following questions:-

1. If the waves in the ocean are timed so that they come to shore every 1.74 seconds, what is the frequency of these waves? (Show your working and don’t forget units).
2. A radio wave has a frequency of 2 MHz (2 MegaHertz = 2 000 000 Hz). Calculate the time period between successive waves.
3. A radio station broadcasts with a wavelength of 160m. If the velocity of the radio signal is 3 x 10⁸ m/s, calculate the frequency of the wave.
4. If all the 1.2 billion people in China jump up and down at the same time, they will create a shock wave that will travel around the Earth in all directions.  This wave will focus and peak on the other side of the Earth, exactly opposite China (around California).  If the circumference of the Earth is 40 000km and the speed of sound on the Earth’s surface is 2850m/s, calculate how long it will take for California to crumble into the sea due to the shock wave.

Here are some more practice questions for you to try. We will then have an assessment on this next week.  Wave-equation-practice-questions (1)

And now the answers …. Grade 9 Integrated Science 1 docwaves practice questions mark scheme

green sine by bdu on flickr

New topic – yay!  We’ll learn about waves. Here are some of the points we’ll try and answer:-

• What is a wave?
• What is the difference between transverse and longitudinal waves?
• What are some examples of transverse and longitudinal waves?
• What are the amplitude, frequency and wavelength of a wave?

Anatomy of Waves

We’ll then take a look at the wave equation       v = f λ

This shows us the relationship between speed of a wave v, the time it takes for a particle to vibrate up and down, and the distance between successive waves λ.  You’ll need your calculators as we practice solving problems in class.

Here are some useful resources for this unit:-

Integrated Science Waves EQ1

Welcome back from break!

Do you remember what we were doing before you went on holiday?  Solubility curves.  That’s right.  Here are the worksheets we used. GCSE Water 04 big and GCSEWater03 Does that ring any bells?

We are going to carry on with this by doing a lab.  Instruction sheet here: solubility curve of potassium nitrate in water

Here are some cool carbon cycle links to check out:

Tutorial
Game
Visualization
Greenhouse effect sim

Richborough, Derelict Power station, Kent by Andreas-photography on flickr

We’re going to try and connect all that we have been learning – respiration, combustion, photosynthesis, food chains – into one big carbon cycle.

This brainpop video will help get you started.

This one on fossil fuels explains where oil, coal and gas come from.

Can you comment on how human activities have impacted the cycle?

Graduated cylinders and beaker filled with chemical compounds by Horia Varlan on flickr

 

Solute + solvent = solution

We’ll investigate factors affecting solubility by designing an experiment, then performing it.  Here is the rubric that will be used to guide this. FINAL Rubric design

These links have some useful information to help you explain your findings. One. Two.

We’ll learn about saturated solutions and what actually happens when a substance dissolves.  See this youtube clip.  We’ll also make some predictions as to the kinds of substances that can dissolve in water.

solubility notes

video notes

Khan Academy video on Solubility

Solubility curves – one and two