This week in science we continued with the dynamic lesson we have been doing. We finished lesson five and lesson seven. In lesson five there was a question that involved the motion of a hockey puck. In the question we had to come up with a story where there was the hockey puck was moving but then an unbalanced force comes. The hockey puck keeps moving though. My story was a player was pushing the puck with their stick and another player started pushing on the puck with their stick in the opposite direction. This story means that even though there are two forces on an object it can still move just at a different velocity.

In lesson seven the questions involved two students, one on roller blades and the other pushed the student down a hallway. The first graph showed a flat. the Y axis was the velocity and the X axis was the time. The flat line meant the student on roller blades was going at the same speed the whole time after the other student pushed her. The first graph had the position on the Y axis and the time on the X axis. In the beginning of the graph there was a line but later in the graph it had a line below it from where it ended. This meant the student was moving forward but then she turned around and went backwards. whenever there are two lines and the second one is behind and below the first that means whatever object it is representing moved backwards.

This week in science we started learning about forces of motion and dynamics. We started by learning how to make a force diagram. To make a force diagram you have to draw a dot to represent the object and then one arrow coming out of the dot and pointing up. Then you have to make one coming down and pointing down. Label the down arrow Force of the Earth on (object). Then label the up arrow the Force of (other source exerting force)on (object). Sometimes there is more then arrrow because sometimes there only the earth is exerting force on the object. Sometimes there are more arrows because there are multiple forces.

We also observed the difference of holding a basketball and a bowling ball. To hold up the bowling ball we have to push up more then we have to when we hold the basketball. It is harder to hold up the bowling ball because it exerts a bigger force on out hands.

We also learned what units we use to tell how great the force is. These are call Newtons. Then we learned how to use them in a number sentence. If I was holding the bowling ball then it might be exerting 10N (Newtons) on my hand and the earth would also be exerting 10N. Then number sentence would be 10N+(-10n)=0N.

This week in science we continued with kinematics. In lesson 12.2 there is a graph showing the motion of a car. In part of the graph there was a flat line and the position and the time were showed on the sides. It said the position of the car was staying the same but the time was getting longer. I learned that if there is ever a flat line, that means whatever the graph is representing has stopped. In the next graph the line is going up and then going down. From this graph I learned that the whatever the graph is representing has sped up and then slowed down.

In lesson 11.7 there was a question that asked how long a line would be if 10 billion people lined up shoulder to shoulder. Then there was another question that asked if the earth could be considered a particle compared to this line. I think the earth could be considered a partical if everyone lined up because the line would be a lot longer then the earth is wide. Then the next question was about how pecise them measurements are. What I learned from these questions is that the calculations will always be a little bit off because you can't get the exact measurement of something.

This week in science we did a series of worksheets. The worksheets helped us learn about the motion of objects. We learned that a trend line is a line on a graoh that represents the average of two sets of datda. On the worksheet 7.1 we had to find the rate that a slow car traveled and the rate a fast car traveled. Then we had out if the two speeds were consant. We got a slow car and measured out a meter. Someone from out group was the time keeper and said when every second passed while someone else made a mark at the front of the car where it was at the second. We did the same thing with a fast car. At the end of the test we mearued between the marks. We looked at the slow car first. The marks were differrent distances apart but were relatively close together. The marks were within 5 centimeters apart so the car didn't move at an exact rate but it moved at an almost constant rate.

When we looked at the results we also realized that the slow car went faster in the first second then the fast car. The second second the same thing happened but then in the third second the fast car sped up and went faster then then slow car.

This week in science we did an experiment with toy cars to see if they stayed at a constant speed or if they sped up or slowed down. We marked off every 10 centimeters on the floor and started the car off at a starting line near the begining of the marks. Someone acted as a metronome and told the other people in the group when every second passed. We started the car and when a second passed someone marked off where the car was. When the car went far enough we stopped it and looked at the marks on the floor. The marks were different distances apart but generally the same. We came to the conclusion that the car was moving at a constant rate. It didn't speed up or slow down.

This week in science we finished learning about rocks and minerals. We finished the contest on the minerals packet. We learned how to find the density of minerals and how to tell the differencs. We had to identify where they were on the hardness scale, cleavage, luster, and color streak. We leaned that sometimes the color streak isn't the same color as the outside color. Some problems that came up while we were doing the packet was we didn't know the exact harness scale so it was hard to place them in order. The measurments on how to find density weren't exact either so we didn't know if it was right.




Also this week we started to learn about physics. We learned about how sometimes you can bemoving and not know it so if you see something you pass, you could think it's moving and you are staying still. Famous scientists strated out with a geocentirc model instead of a heliocentric model because they thought the earth was still and all other planets moved. If they had known the earth moved they would have known that the planets revolve around the sun.



We also learned that if there are two cars and one is moving forwards and one stays still, the car that's moving could think the other car is going backwards. So if something is still, depending on the movement of something else, that something else could still think the stationary object is moving.

This week in science we classified cookies and chips. We learned about how there are different kinds of rocks in one whole rock. There are ingrediants on cookies that make a cookie so a rocks and cookies are alike.

We also learned about James Hutton. James Hutton came up with the theory of uniformitarianism. It is the theory that erosion and sedimentation have always been modifying the earth. It also says that erosion and sedimentation happen over a very long period of time. People didn't accept his theory because earthquakes and things like that happened very fast. They changed the earth very fast and his theory said it happens slowly.

We also learned about which rocks are harder then other rocks. Diamond is the hardest rock and Talc is the softest. We learned about the scale id hardness which is called the Mohs Scale. Talc is the softest the next are Gypsum, Calcite, Flourite, Apatite, Quartz, Corundum, and Diamond is the hardest. Talc Gypsum and Flourite can be scratched by a fingernail but the rest are to hard. Diamonds can scratch glass with little effort.