Cups 1 - Properties Of Matter

Properties of Matter: Part One – The Particle Model of Matter Materials needed: Internet access, set of syringes, hot/cold water, Petri dishes, overhead projector, food coloring – LIQUID NITROGEN AND BALLOON!

1. a) What kind of evidence can you site to argue that there is something in the syringe?

b) Make a sketch of what you think is inside.

Does your sketch reflect a “model” of mater? Is a model an analogy? Why might it be important for a teacher to be aware of student’s incorrect models? POSSIBLE STUDENT ALTERNATE

PRIOR EXPERIENCE THAT THIS ALTERNATE

“BAD” ANALOGY THAT ALTERNATE CONCEPTION IS

CONCEPTION Air is a continuous substance

CONCEPTION IS BASED ON Our experience with matter is that it seems to be continuous. It seems like it can be divided on an on… You cant see air – but it is always around and in most spaces that we are familiar with

BASED ON Air IS LIKE water – both are continuous substances that stretch to fit container - It is like we are in an aquarium, but instead of water, we have air

2. Put your finger on the end of the syringe to prevent anything from coming in or going out – then pull the syringe back. Make a new sketch of what is inside.

POSSIBLE STUDENT ALTERNATE CONCEPTION Air is a continuous substance that has elasticity

PRIOR EXPERIENCE THAT THIS ALTERNATE CONCEPTION IS BASED ON When the syringe is pulled back, there is a resistive force

“BAD” ANALOGY THAT ALTERNATE CONCEPTION IS BASED ON Air IS LIKE a rubber band – when it it stretched, it gets longer but pulls back

NEW OBSERVATION: Push all the air out of your syringe and then put your finger over the end to block any air from getting back in.

A) What does the “AIR IS LIKE A RUBBER BAND” model predict will happen? B) What do you observe? C) How is this a “discrepant event” for a learner who has the AIR

IS LIKE A RUBBER BAND alternate conception? D) Does this new observation prove that air is made up of particles? How might students with the alt conception devise alternate explanations?

3. We use a particle model for matter. What is in-between the particles?

4. What evidence do we have that matter really is made of particles (and does not just seem to be made of particles)? VIDEO CLIP – Observing Brownian Motion http://www.microscopy-uk.org.uk/dww/home/hombrown.htm

http://galileo.phys.virginia.edu/classes/109N/more_stuff/Applets/brownian/brownian.html 

Did Einstein’s explanation of Brownian Motion PROVE that matter was made of particles?

5. DEMO: Food coloring is placed in a Petri dish that has either cold or hot water. A) What does the particle model of matter predict will happen? B) What would a continuous model of matter predict?

6. THIS IS BIG!!! How does the particle model of matter explain the differences observed between gasses, liquids and solids?

Properties of Matter: Part Two – How many particles?

"Nu­cle­er"  not  "Nuke­u­lar"

1. The atom depicted here has 7 protons. a) What element is it?

b) Why are there also 7 electrons orbiting the nucleus?

c) How can we use the periodic table to figure out how many neutrons are in the nucleus?

d) Would this be the same element if the number of protons was different?

e) Would this be the same element if the number of electrons was different?

f) Would this be the same element if the number of neutrons was different? What are the different “versions” of a particular element called?

2. The number of protons and neutrons in a particular element is commonly denoted by the elements abbreviation with two numbers. The top number is the atomic mass number (total number of protons and neutrons in the nucleus) and the bottom number is the atomic number(the total number of protons).

How many protons and neutrons does Uranium have? a) 238 protons and 238 neutrons b) 238 protons and 92 neutrons c) 146 protons and 92 neutrons d) 92 protons and 146 neutrons

238 92 U

3. As long as atoms have the same number of protons, they are all the same element with the same chemical properties. Atoms with the same number of protons, but different numbers of neutrons are called 1 2 3 "isotopes". Hydrogen has three naturally occurring isotopes:    1H (protium),    1H (deuterium), and    1H (tritium). Most isotopes don't have their own special names, so they are commonly referred to by stating the isotope's elemental name followed by its atomic mass number. So these three elements can be referred to as H-1, H-2, and H-3 respectively.

How would you refer to these two isotopes of carbon?   6 C (stable) 12

and   6 C (unstable) 14

How would you sketch each isotope?

4**. What is the difference between an atom, element and molecule?