1. Warm-Up, 09.14.2009 The force of Earth’s gravity pulls all objects downward. However, objects such as rocks seem to fall faster than feathers or leaves. Do objects with more mass fall faster? La force de la pesanteur de la terre tire tous les objets en bas. Cependant, les objets tels que des roches semblent tomber plus rapidement que des plumes ou des feuilles. Les objets avec plus de masse tombent-ils plus rapidement ? La fuerza de la gravedad de la tierra tira de todos los objetos hacia abajo. Sin embargo, los objetos tales como rocas parecen caer más rápidamente que plumas o las hojas. ¿Los objetos con más masa caen más rápidamente?

2. Vector Map Activity (Pre-test review) Working in small groups, students will create a vector map during the first half of the period. Each group will "hide" a commonplace object at the "finish" for the group following their map to find. They then will be given another group's vector map to follow during the last half of the period.

3. Materials meter stick centimeter ruler compass paper

5. A different starting position is assigned for each lab group. Each lab group must clearly indicate this position on their list of vectors.

8. Test #2 Motion & Forces

9. What do we use to measure mass? The difference between mass and weight causes a lot of confusion amongst a lot of people. Put simply, weight is a measure of gravity's effect on something. Mass is the amount of matter in an object. Move to a different planet and an object's weight will change, but its mass will be the same. There are a couple of ways to measure mass. The most common method is to use a balance. Hey, wait a minute! (you should be saying) People weigh stuff all the time with a balance! Think about it. If you go to a different planet, the balance weights change by the same factor as the object you are measuring. Your mass measured with a balance would be the same on the moon as it is on Earth. There are a couple of other neat tricks, but they only really work perfectly in no-gravity, no-friction environments. For example imagine a big rock floating in space. Give it a slap with a calibrated hand so you know exactly how much energy you gave it. Now measure how fast the rock is moving. That new speed is proportional to its mass. In space you weigh nothing, but your mass is the same, so a space bully can still shove the 98 pound weakling even though they both weigh 0 pounds.

10. Questions from reading!!!

11. Gravity Launch Lab: Copy the chart below. Measure the mass of 2 objects and a flat sheet of paper. Drop the first object from a height of 2.5m and use a stopwatch to measure the time it takes for a softball to hit the floor. Record the time in the data table. Repeat step 2 using your second object and the flat sheet of paper. Record the times in your data table. Crumple the flat sheet of paper into a ball, and measure the fall time. Write a paragraph comparing the times it took each item to fall. From your data, infer if the speed of a falling object depends on the object’s mass.