Forces and Motion Understanding Speed MightyOwl Science 3 rd Grade

hello this is mighty owl want you to imagine car it might be standing still parked in the garage or it might be driving on the street when it moves the car changes its location and its position this changing of location or position is called motion many objects change their position over time some slowly others little faster think about animals plants waves even the wind you are moving almost all the time as well even if you're sitting still you're always breathing and your lungs are always inflating and deflating your heart is always beating pumping blood throughout your entire body the cells in your body are constantly transporting water oxygen and nutrients fighting against bacteria growing and multiplying there are ton of things in motion all around us so now that we've determined that motion is everywhere let's talk today about something called speed speed is measure of how much motion something has speed is type of rate it measures how much something changes over period of time speed measures how much distance has changed after some time has passed if you know the distance car travels in certain amount of time let's say 40 miles in one hour then you can also calculate the speed of the car sometimes the speed of car doesn't change during its trip so you can say the car is traveling at constant speed if that makes you think about highway that's exactly the right idea that's place where car can travel at constant speed you've probably heard of cruise control right it's setting you can use while driving car and the car then drives at the same speed even if your foot isn't pressing on the gas pedal if you're using cruise control while driving your car is traveling at constant speed most objects don't move at constant speed for very long though you don't move at the same speed either just imagine how many times you slow down and speed up on the way to school especially if you're running late for your first period and dodging all the other people in the halls moving objects change speed many times while in motion think about your father driving the car on highway using cruise control if there's an accident or traffic jam up ahead he may have to change the speed and slow down or even stop the car the speed of your car in the city may also depend on the speed limits or depend on traffic lights you may need to stop at traffic light if it's red or you might want to speed up to pass another car there are other examples marathon runners don't run at constant speeds during the entire race at the starting line there are many runners all crowded together and they have to move more slowly but as the crowd thins out runner can increase their speed runner may also slow down when going up hill or they may increase their speed when going downhill it might seem obvious but if an object is moving fast it can travel distances in short amount of time just imagine the fastest runner in your class and the slowest one both of them have to run the same distance but the time they take to run that distance will be different think about those marathon runners again some of them will finish the race sooner than others but in the end everyone still runs the same distance don't they in nature there are some animals that are known for their speed the fastest animal on the planet for example is the cheetah when it's chasing its dinner and some of the slowest animals are snails sloths koalas and sea horses speed can be detected not only in animals but also in some natural phenomena think about the speed of light or the sonic boom formed by lightning strike or even the earth revolving around the sun we know that the earth takes 365 days to revolve around the sun but did you know that the speed is about 660 miles per hour incredible speed is fascinating people love things that move fast fast cars fast animals or marathon runners sprinting to the finish line maybe that's why the most popular olympic events involve speed let's recap speed is the distance traveled over period of time it's how fast an object is moving greater speed means an object is moving faster less speed means it is moving slower if it isn't moving at all it has zero speed and if it's moving at the same speed we call that constant speed so far so good now let's speed up to the next video lesson