Week of November 16, 2009

Thing learned: predicting when two things will crash

Learned by: making graphs, tables, and functions.

Thing learned: coming up with speed per unit

Learned by: delta position divided by delta time or x2-x1/t2- t1

Thing learned: when two things are a certain distance apart

Learned by: making tables and/or graphs

Thing learned: relationship between speed and velocity

Learned by: |v|= speed

Thing learned: "dot diagrams suck"

Learned by: they don't tell you enough about the motion of an object

Thing learned: making motion diagram

Learned by: doing problems like the one with the motorcycle and the moon. You can make one by adding arrows, an origin, positive and negative directions, and labeling ( V1, V2 ect.)

It is important to know these things so that you can read graphs and describe motion. If you know this than you will be able t accurately display data to anyone who wants to read it. You can show it better than a dot diagram or picture. Scientists use this information to make roads and speed limits. You also need to know this if you are a pilot (when two planes will collide) or astronauts. If you are making cars you need to know this stuff. And if you are coming up with a speed limit you need to make sure that cars will not flip over or skid when making a turn.

week of November 2, 2009

This week in science class i learned about graphing and describing data and writing functions.

I learned these ideas by:

Drawing trend lines to explain the graph. A trend line points to the general direction that the points are going to. They don't need to be exactly on the points but they have to have an arrow at the end.

Writing Functions. To make a function you write the dependent variable and put the independent variable in parenthesis next to it. Then you multiply the physical quantity number by the two units and then by the variable.

Using variables as numbers we don't know. This is hard to explain but it is like using a letter in place or a number that we don't know, like in algebra. For example, the starting time of a jogger could be t1 and the ending could be t2.

Coming up with variable expressions. For example, if you want to find out how long the jogger ran for you would have to do t1-t2. It is hard to figure out these expressions when the questions and situations become more complicated.

It is important to know these ideas so you can make graphs if you are a salesperson or you are trying to convince someone to do something. KNowing this stuff will help you express your data once it is collected, so you can display it in a way that is easy to understand and work with. It is good to find patterns in your data so you can make predictions about what will happen (like people do when choosing stocks). It helps to know the independent and dependent variable in your data.

Week of October 26, 2009

I learned about showing motion in tables and graphs.

I learned this by doing several experiments.

We drew a picture of a car activity and labelled negative and positive sides. Then we learned how to make dot diagrams and turn those dot diagrams into charts. (position vs. time)

We also learned to switch the axis's. When something is headed toward the negative side the graph needs to be adjusted. We can draw this graph by making a big plus sign and labeling the positive and negative sides of the y and x axis. Then you draw your graph going down into quadrant 4, or the positive x negative y box.

We experimented with how to draw graphs of things not moving and how to make graphs curve. We also made our own situations to pre-existing graphs.

Then we learned how to compare dot diagrams and graphs. We learned about positive and negative motion. when a line on a graph is going up, it is positive motion, when it is going down it is negative motion.

Lastly we learned to make index's for different kinds of popcorn brands to find out which pops fastest. An index is a number that helps to compare things. It is similar to a ratio.

It is important to know these things because then you can show how things are moving and discover important things like when two asteroids will collide or two objects. Also, this will help you understand and help you make graphs in math class, when you have to do similar things. Overall, I think it is important to know these things to explain and understand motion.